**Simple Substrate Culture in Arid Lands**

Usama Ahmed Aly El-Behairy

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/59628

## **1. Introduction**

The limited water resources are the major factor that drew the attention towards the use of intensive agriculture in arid land. Protected cultivation was the first step, which started initially at late seventies and intensified at mid-eighties. Maximizing crop yield per square meter of soil as well as per cubic meter of water could be achieved using soilless culture systems [12]. The need for the use of soilless culture is becoming more important in arid lands than several years ago in order to increase the water use efficiency. In addition, continuous cultivation of crops resulted in poor soil fertility, which in turn has reduced the opportunities for natural soil fertility build up by microbes. This situation has led to poor yield and quality. In addition, conventional crop cultivation in soil (conventional open field agriculture) is difficult as it involves large space, large amounts of water and a huge number of labors [1].

Soilless agriculture means growing plants in the absence of land as the normal agricultural, where soil not used as a medium for agriculture but used as a support to the system. This technique can be an alternative to the conventional cultivation in the soil which has problems and difficult. In addition, soilless culture is possibly the most intensive method of crop production in today's agricultural industry in combination with greenhouses.

In protected cultivation, the high levels of crop and continuous cropping inevitably leads to problems of pests and diseases in the soil. The accumulation of these problems leads to a loss of yield and eventually of the crop. Cropping can only continue if some form of sterilization of the soil or rotation of crop can take place. Steam sterilization is not economically viable & not efficient, the use of methyl bromide banned in many European states, and it will band. For production to continue there is inevitably a move towards some form of soilless culture or soil replacement cultivation.

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The use of soilless culture has substantially increased during the last decade as it contributes to the intensification of horticultural production and provides high crop yields even in areas with adverse growing conditions [12].

This chapter will discussed the importance of soilless culture of soilless culture in arid land, the constrain of using this type of cultivation, the type of soilless culture used in arid lands and the suitable types of substrate culture for arid lands.

#### **2. Importance of soilless culture in arid land**

Soilless culture technique provides a large numbers of advantages could be summarized as follows [9]:


#### **3. Why we have to move to this type of cultivation in arid lands**

Most of the grower in the arid region now a day should move to the soilless culture for the following reasons:

#### **3.1. Increase productivity**

The matter of increased yields with the application of soilless culture should 'be examined carefully. It is true that precise control of nutrition to the plants grown in soilless cultures will result in higher yields and quality, but this does not necessarily mean that yields from the best cultures in soil are inferior. Nevertheless, it is difficult to believe that the fast increase in area in soilless culture in the Netherlands and other European countries would have occurred unless commercial growers were confident of some yield increase to help offset the additional cost of soilless culture.

It is of course understandable that if there are soil problems, (i.e. poor soil. saline soil, toxic soil, etc.), then soilless culture will produce much better crops. Many reports published during the last 15 years presenting results on comparison of soilless methods and soil. Most of them show advantages towards the soilless systems, but his was usually been due to a combination of factors such as reduction of labor, higher yields and the greater uniformity of quality due to them or uniform conditions of growth. However, it must mentioned that in many experi‐ ments the management of crops in the soil is not controlled properly [9].

#### **3.2. Control of plant nutrition**

The use of soilless culture has substantially increased during the last decade as it contributes to the intensification of horticultural production and provides high crop yields even in areas

This chapter will discussed the importance of soilless culture of soilless culture in arid land, the constrain of using this type of cultivation, the type of soilless culture used in arid lands

Soilless culture technique provides a large numbers of advantages could be summarized as

**•** Standardization of the culture, and of the root environment in particular.

**•** Drastic reduction of energy input for the conditioning of the root environment.

**•** Excluding soil infection and hence the danger of disinfectant residues.

**•** Better control of vegetative and generative plant development.

**•** More possibilities for culture mechanization and automatic control.

**3. Why we have to move to this type of cultivation in arid lands**

Most of the grower in the arid region now a day should move to the soilless culture for the

The matter of increased yields with the application of soilless culture should 'be examined carefully. It is true that precise control of nutrition to the plants grown in soilless cultures will result in higher yields and quality, but this does not necessarily mean that yields from the best cultures in soil are inferior. Nevertheless, it is difficult to believe that the fast increase in area in soilless culture in the Netherlands and other European countries would have occurred

with adverse growing conditions [12].

follows [9]:

and the suitable types of substrate culture for arid lands.

70 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

**2. Importance of soilless culture in arid land**

**•** Crop production where the soil is unsuitable. **•** Drastic reduction of the water consumption.

**•** Efficient use of nutrients.

**•** Rationalization of labor.

following reasons:

**3.1. Increase productivity**

**•** Earlier and higher production. **•** Qualitatively better production. The accurate control of plant nutrition compared to soilless culture is also one of the most important advantages of soilless culture. This can be seen from: the point of view of the controlled concentrations, which can be applied to the various crops, various environments, stage of plant growth, etc. In addition, harmful elements to plants, above certain concentrations can be kept within safe concentrations (i.e. Mn, B, Zn, Cu, Pb, etc.)

Another important advantage related to plant nutrition in soilless culture, is the uniformity with which nutrient elements can be supplied to the substrate. This is particularly true with water culture and the more sophisticated systems and less true for the aggregate cultures, especially the simplest ones using surface drip irrigation systems (sand culture, etc.).

When using water cultures or aggregate cultures with inert substrates the level of nutrients, supplied to the new crops those chosen by the manager. This is not the case with soil cultures where in many cases excess nutrient levels in the soil from the previous crops produce salinity.

Another advantage of the soilless culture related to plant nutrition is the ability to control the pH and the E.C. of the nutrient solution according to the requirement of the crop and the environmental conditions. Similar control in soil cultures is very difficult and expensive [9].

#### **3.3. Water economy and control**

Water is the most important factor for crop production. Protected crops require large amounts of water due to exclusion of rainfall when crop production is required in hot, arid regions of the world; water is like to be a limiting factor not only of availability but also of quality and cost.

The advantage of soilless culture related to the ease of irrigation applies mainly to certain soilless systems, such as NFT and other true hydroponic systems (where the plants have their roots immersed into the nutrient solution) and to sub-irrigated substrate culture, and is not fully applicable to the rest of the soilless cultures using various inorganic or organic substrates. In fact, watering the later, the frequency and duration of irrigation is much more critical substrates with low water holding capacity, compared to soil.

With reference to water saving, certain soilless systems, for instance the closed or recirculated ones, undoubtedly economize water because drainage and evaporation from the surface eliminated by the design and operational scheme of the systems (NFT, "closed" systems, subirrigated soilless culture). In addition, with soilless culture, more accurate water supply control practiced.

Furthermore, water culture and sub-irrigated substrate systems save much labor in the time consuming task of checking and cleaning irrigation nozzles. On the contrary, crops grown on substrates and soil, require frequent examination of trippers as these can easily be blocked by calcium carbonate or other compounds especially with a "hard" water supply. The blockage problem can be eliminated either by acidification of nutrient solution or by pretreatment of irrigation water [9].

#### **3.4. Reduction of labor requirement**

Out of soil production exclude all cultural practices associated with the cultivation of the soil, sterilization of soil, weed control, etc. Labor requirement for soilless culture is not similar to all soilless systems. Therefore, the system itself, the degree of automation, the type of substrate, the number of crops raised on each substrate, etc. but in any case, generally speaking, there is a saving in labor impute when soilless culture employed [9].

#### **3.5. Sterilization practices**

The greenhouse soil must be free from any soil-borne pathogens before the establishment of any new crop. Sterilization is a difficult and costly operation, but necessary and of great importance. It is justified because the greenhouse business require high investment in structures, facilities, plant materials, running costs, etc. and the need to obtain maximum yields and returns, is obvious to have an economically viable operation. The most effective method of soil sterilization is by steaming, but the method is expensive due to the high cost of energy and labor, therefore its application eliminated. Chemical sterilization is less expensive but not without disadvantages, i.e. the use of formaldehyde had the problems of fumes which are highly phytotoxic and the most important chemical, methyl bromide, a very toxic material to handle, has the problem of chemical residues (bromide ions taken up by the crop) and environmenta1 pollution.

It is therefore, of great advantage the cultivation of crops outside of the soil as there is no need for sterilization when materials and substrates used only for one time, because spreading of diseases avoided. When "closed" soilless culture used depending on the system, the need for sterilization varies, i.e. to clean "true hydroponic" culture structures, following the removal of all debris, etc., a dilute rate of formaldehyde used, followed with clean water. In the NFT system, the film that forms the gullies can be replaced. When solid substrates are used, steam or chemical sterilization should be applied if the material is to be used again. In this case, the application of both is easier and economic but in any case, sterilization of soilless culture systems is easier than soil sterilization [9].

#### **3.6. Control of root environment**

Possibilities for more accurate control of root temperature, root oxygen supply are more easily to achieve in soilless cultivation[9].

#### **3.7. Multiple crops per year**

Due to the absence of the cultivation techniques, operations like soil cultivation, soil steriliza‐ tion etc., the number of crops per year is increased, in a given production area, because the time interval between crops is nearly short [9].

#### **3.8. Unsuitable soil**

follow:

*5.1 Deep water culture* 

*5.2 Nutrient Film Technique (NFT)*

collected and returned to the catchment tank.

eliminated by the design and operational scheme of the systems (NFT, "closed" systems, subirrigated soilless culture). In addition, with soilless culture, more accurate water supply control

Furthermore, water culture and sub-irrigated substrate systems save much labor in the time consuming task of checking and cleaning irrigation nozzles. On the contrary, crops grown on substrates and soil, require frequent examination of trippers as these can easily be blocked by calcium carbonate or other compounds especially with a "hard" water supply. The blockage problem can be eliminated either by acidification of nutrient solution or by pretreatment of

Out of soil production exclude all cultural practices associated with the cultivation of the soil, sterilization of soil, weed control, etc. Labor requirement for soilless culture is not similar to all soilless systems. Therefore, the system itself, the degree of automation, the type of substrate, the number of crops raised on each substrate, etc. but in any case, generally speaking, there is

The greenhouse soil must be free from any soil-borne pathogens before the establishment of any new crop. Sterilization is a difficult and costly operation, but necessary and of great importance. It is justified because the greenhouse business require high investment in structures, facilities, plant materials, running costs, etc. and the need to obtain maximum yields and returns, is obvious to have an economically viable operation. The most effective method of soil sterilization is by steaming, but the method is expensive due to the high cost of energy and labor, therefore its application eliminated. Chemical sterilization is less expensive but not without disadvantages, i.e. the use of formaldehyde had the problems of fumes which are highly phytotoxic and the most important chemical, methyl bromide, a very toxic material to handle, has the problem of chemical residues (bromide ions taken up by the crop) and

It is therefore, of great advantage the cultivation of crops outside of the soil as there is no need for sterilization when materials and substrates used only for one time, because spreading of diseases avoided. When "closed" soilless culture used depending on the system, the need for sterilization varies, i.e. to clean "true hydroponic" culture structures, following the removal of all debris, etc., a dilute rate of formaldehyde used, followed with clean water. In the NFT system, the film that forms the gullies can be replaced. When solid substrates are used, steam or chemical sterilization should be applied if the material is to be used again. In this case, the application of both is easier and economic but in any case, sterilization of soilless culture

practiced.

irrigation water [9].

**3.5. Sterilization practices**

environmenta1 pollution.

systems is easier than soil sterilization [9].

**3.4. Reduction of labor requirement**

a saving in labor impute when soilless culture employed [9].

72 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

Soilless culture offers an ideal crop alternative to soil culture when there is no soil available at all, or there is no suitable soil for crop production, when soil salinity is higher or there are toxic substances into the soil and finally there is an accumulation of soil pathogens into the soil [9]. **3.6 Control of root environment** Possibilities for more accurate control of root temperature, root oxygen supply are more easily to achieve

number of crops per year is increased, in **a** given production area, because the time interval between crops is nearly

#### **4. The constraint points for soilless culture in arid lands 3.7 Multiple crops per year** Due to the absence of the cultivation techniques, operations like soil cultivation, soil sterilization etc., the


in soilless cultivation.


 The high temperature most of the year. The availability of the soft water. The needed water for the cooling.

**•** The availability of the fertilizer for making the nutrient solution in the country. **4. The constraint points for soilless culture in arid lands**

#### **5. Soilless culture system for producing vegetables in arid lands** The availability for the equipment in the country. The availability of the fertilizer for making the nutrient solution in the country.

Soilless culture divided into three major branches according the root growing media **5. Soilless culture system for producing vegetables in arid lands**

Soilless culture divided into three major branches according the root growing media

mixing water with air. The plants are flouting on the nutrient solution using polystyrene sheet.

Hydroponics is a technology for growing plants in nutrient solutions (water containing fertilizers). There are different types of hydroponics according the movement of the nutrient solution and the two main systems as

The plant roots grow in containers filled with water containing fertilizers (static water). In this system water mixed with nutrient solution and oxygen applied to the plants through nutrient solution using air pump or by

In this system, the roots of the plants grow in a shallow film of water and nutrient solution inside cultivation channel or tube. The plants inserted in polyethylene (black on white) channel laid on a slope bed. The nutrient solution pumped into the channels in a thin film of nutrient solution and the excess nutrient solution

Hydroponics is a technology for growing plants in nutrient solutions (water containing fertilizers). There are different types of hydroponics according the movement of the nutrient solution and the two main systems as follow:

#### **5.1. Deep water culture**

The plant roots grow in containers filled with water containing fertilizers (static water). In this system water mixed with nutrient solution and oxygen applied to the plants through nutrient solution using air pump or by mixing water with air. The plants are flouting on the nutrient solution using polystyrene sheet.

#### **5.2. Nutrient Film Technique (NFT)**

In this system, the roots of the plants grow in a shallow film of water and nutrient solution inside cultivation channel or tube. The plants inserted in polyethylene (black on white) channel laid on a slope bed. The nutrient solution pumped into the channels in a thin film of nutrient solution and the excess nutrient solution collected and returned to the catchment tank.

**Figure 1.** Different systems of deep-water culture and nutrient film technique

Photo (1). Different systems of deep-water culture and nutrient film technique

#### **5.3. Aeroponics**

In this system, nutrient solution sprayed as a fine mist in sealed root chambers. The plants are grown in holes in panels of expanded polystyrene or other material. The plant roots suspended in midair beneath the panel and enclosed in a spraying box. The box sealed so that the roots

are in darkness (to inhibit algal growth) and in saturation humidity. A misting system sprays the nutrient solution over the roots periodically. The system normally turned on for only a few seconds every 2-3 minutes. This is sufficient to keep roots moist and the nutrient solution aerated [1]. holes in panels of expanded polystyrene or other material. The plant roots suspended in midair beneath the panel and enclosed in a spraying box. The box sealed so that the roots are in darkness (to inhibit algal growth) and in saturation humidity. A misting system sprays the nutrient solution over the roots periodically. The system normally turned on for only a few seconds every 2-3 minutes. This is sufficient to keep roots moist and the nutrient solution aerated.

In this system, nutrient solution sprayed as a fine mist in sealed root chambers. The plants are grown in

**Photo (2): Aeroponic system for producing lettuce Figure 2.** Aeroponic system for producing lettuce

#### **5.4 Substrate culture 5.4. Substrate culture**

**5.3 Aeroponics**

Hydroponics is a technology for growing plants in nutrient solutions (water containing fertilizers). There are different types of hydroponics according the movement of the nutrient

The plant roots grow in containers filled with water containing fertilizers (static water). In this system water mixed with nutrient solution and oxygen applied to the plants through nutrient solution using air pump or by mixing water with air. The plants are flouting on the nutrient

In this system, the roots of the plants grow in a shallow film of water and nutrient solution inside cultivation channel or tube. The plants inserted in polyethylene (black on white) channel laid on a slope bed. The nutrient solution pumped into the channels in a thin film of nutrient solution and the excess nutrient solution collected and returned to the catchment tank.

 **Deep water system Nutrient Film Technique**

Photo (1). Different systems of deep-water culture and nutrient film technique

In this system, nutrient solution sprayed as a fine mist in sealed root chambers. The plants are grown in holes in panels of expanded polystyrene or other material. The plant roots suspended in midair beneath the panel and enclosed in a spraying box. The box sealed so that the roots

**Figure 1.** Different systems of deep-water culture and nutrient film technique

**5.3. Aeroponics**

solution and the two main systems as follow:

74 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

**5.1. Deep water culture**

solution using polystyrene sheet.

**5.2. Nutrient Film Technique (NFT)**

In this system, a solid medium provides support for the plants. As in liquid systems, the nutrient solution delivered directly to the plant roots. The substrate culture divided according to drainage procedure into two major systems according to drainage procedure In this system, a solid medium provides support for the plants. As in liquid systems, the nutrient solution delivered directly to the plant roots. The substrate culture divided according to drainage procedure into two major systems according to drainage procedure

#### **5.5. Open system**

;l;l;

**Open system Closed system** The open system is that when the nutrient solution applied to the system with the plants grow and then drained off as waste.

;km;,l Because the leached or drained solution is not recirculated to the feeder tank, it does not require monitoring and adjustment. Once mixed, it is generally used until depleted. In addition, the quality of the irrigation water is less critical. A content of up to 500 ppm of extraneous salts is easily tolerated, and for some crops (tomatoes, for example) even higher salinities are permis‐ sible, although not desirable. It is advisable to monitor the growing medium, particularly if

**Photo (3). Scheme of the open and closed system for substrate culture systems** 

**Photo (2): Aeroponic system for producing lettuce**

systems according to drainage procedure

**5.3 Aeroponics**

aerated.

In this system, a solid medium provides support for the plants. As in liquid systems, the nutrient solution delivered directly to the plant roots. The substrate culture divided according to drainage procedure into two major

In this system, nutrient solution sprayed as a fine mist in sealed root chambers. The plants are grown in holes in panels of expanded polystyrene or other material. The plant roots suspended in midair beneath the panel and enclosed in a spraying box. The box sealed so that the roots are in darkness (to inhibit algal growth) and in saturation humidity. A misting system sprays the nutrient solution over the roots periodically. The system normally turned on for only a few seconds every 2-3 minutes. This is sufficient to keep roots moist and the nutrient solution

**Photo (3). Scheme of the open and closed system for substrate culture systems Figure 3.** Scheme of the open and closed system for substrate culture systems

the irrigation water is relatively saline or if the operation is located in a warm, high sunlight region. To avoid salt accumulation in the medium, enough irrigation water is used to allow a small amount of drainage or "leaching" from the bags. This drainage should be collected and tested periodically for total dissolved salts [1].

#### **5.6. Closed system**

Closed system works in the same way as open system with on important difference that nutrient solution which run-off after each application is collected and recirculated to be used in successive irrigation times.

Closed systems are economical in the use of nutrients, but require frequent monitoring and adjustments of the nutrient solution. Measuring (EC) is a convenient check of total salt concentration, but provides no data on the concentration of major elements, and it is virtually unaffected by the amounts of trace elements present. Periodic chemical analyses are required, usually every two or three weeks for major elements and every four to six weeks for trace elements.

Small farmers commonly practice this regime: Begin with a new solution; at the end of a week add one-half of the original formula to the solution. At the end of the second week, dump the remaining mixture from the tanks or sumps and start all over again [1].

#### **6. Growing media used for growing horticulture crops in the arid lands**

#### **6.1. Function of growing media**


**•** Provides support for the plant.

Some individual materials (substrates) can provide all four functions, but not at the required level of each. For example, sand provides excellent support and gas exchange but has insuf‐ ficient water-and nutrient supplying capacity [9].

#### **6.2. Characteristics of appropriate substrates**

**•** Capacity to hold water

the irrigation water is relatively saline or if the operation is located in a warm, high sunlight region. To avoid salt accumulation in the medium, enough irrigation water is used to allow a small amount of drainage or "leaching" from the bags. This drainage should be collected and

**Photo (3). Scheme of the open and closed system for substrate culture systems** 

**Figure 3.** Scheme of the open and closed system for substrate culture systems

In this system, nutrient solution sprayed as a fine mist in sealed root chambers. The plants are grown in holes in panels of expanded polystyrene or other material. The plant roots suspended in midair beneath the panel and enclosed in a spraying box. The box sealed so that the roots are in darkness (to inhibit algal growth) and in saturation humidity. A misting system sprays the nutrient solution over the roots periodically. The system normally turned on for only a few seconds every 2-3 minutes. This is sufficient to keep roots moist and the nutrient solution

In this system, a solid medium provides support for the plants. As in liquid systems, the nutrient solution delivered directly to the plant roots. The substrate culture divided according to drainage procedure into two major

**Open system Closed system**

Closed system works in the same way as open system with on important difference that nutrient solution which run-off after each application is collected and recirculated to be used

Closed systems are economical in the use of nutrients, but require frequent monitoring and adjustments of the nutrient solution. Measuring (EC) is a convenient check of total salt concentration, but provides no data on the concentration of major elements, and it is virtually unaffected by the amounts of trace elements present. Periodic chemical analyses are required, usually every two or three weeks for major elements and every four to six weeks for trace

Small farmers commonly practice this regime: Begin with a new solution; at the end of a week add one-half of the original formula to the solution. At the end of the second week, dump the

**6. Growing media used for growing horticulture crops in the arid lands**

**•** Must provide gas exchange between roots and the atmosphere outside the root substrate

remaining mixture from the tanks or sumps and start all over again [1].

tested periodically for total dissolved salts [1].

**Photo (2): Aeroponic system for producing lettuce**

76 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

systems according to drainage procedure

**5.4 Substrate culture**

;km;,l

;l;l;

**5.3 Aeroponics**

aerated.

**5.6. Closed system**

elements.

in successive irrigation times.

**6.1. Function of growing media**

**•** Serves as a reservoir for plant nutrients

**•** Serves as a reservoir for water available for plants

The capacity to hold and drain surplus water depends on the texture of the medium, the size and form of its granules and the permeability. The smaller granules have more surfaces, are close to each other, and therefore, can hold more water. Also the uneven form of granules has a surface area more than granules of even or round form thus the first has higher capacity to hold water.

Consequently, the size of granules should be appropriate so that it can hold proper quantity of water suitable to the crop to be grown [1].

**•** The substrate should have good aeration and good drainage capacity

The substrate should have a good drainage capacity for draining surplus water and therefore, ensures good aeration around roots. Therefore, we should avoid substrate/medium with fine granules which impedes the movement of oxygen through such granules, reducing the overall aeration condition in the growing environment and leads to asphyxiation of plant roots [1].

**•** The substrate should be free from harmful or poisonous materials

The substrate should be free from any material, which may cause harm to plant roots or affect plant growth such as sand and small stones of lime origin (contain calcium carbonate). This should be avoided as it can increase the nutrient solution pH to more than 7. This increase leads to sedimentation of iron and phosphorus causing a symptom of deficiency although they exist in the solution.

**•** The substrate should be supportive to plants growing in it

The substrate should be acting to fix the plants properly. This depends on the texture of the substrate, which should be medium-heavy to fix plant roots [1].

**•** To be free from diseases incitements

The substrate should be free from different pests and insects so that it would not form a source of infecting plants by different diseases [1].

**•** To be free from salinity

The substrate should be free from salinity to avoid affecting the growing plants. For instance, the medium made of wood dust usually contains high concentration of sodium chloride due to soaking the wood in salt solution for long periods [1].

**•** The substrate should be free from weed seeds

This is to avoid being a source of weeds, which will grow and compete with the main crop for nutrition and water. In many cases, weeds would also be a host for some diseases, which would infect and damage the growing plants [1].

**•** To be slow in the decomposition process

In case of using organic medium, it would preferably be of slow deteriorating nature so that it continues to be in the best condition for the longest period possible. This will reduce the cost of changing the substrate annually [1].

**•** To be easily transported, handled, and less expensive

There are many kinds of substrates but it is important that the selected one be available in several locations to facilitate its handling and transportation. This would result in reducing the cost of transportation and hence, the preliminary cost of establishing the roof garden. The price of the substrates should be appropriate and acceptable so that the system adopted by all categories of the society [1].

#### **6.3. Types of growing media**

Growing media "substrates" can classified as follows:

**Inert media:** A solid inert material for supporting the plant and provides air and water availability conditions to the roots such as perlite, sand, Rockwool, volcanic gravel, pum‐ ice...etc.

**Organic media:** A natural organic material for supporting the plant such as peat moss, coconut fibers, coco peat, rice hush, wood bark...etc.

There are several raw materials, which used as substrates for roof farming. Such materials differ from one another about its physical characteristics. Due to variations and multiplicity in the forms and types of materials available in the surrounding environment, there is a need for particular criteria, which enables us to select the appropriate material for an agricultural medium (substrate) [9].

#### *6.3.1. Organic substrates*

#### *6.3.1.1. Peat moss*

The Peat moss considered the most common substrate and widely used at global level. It is a decomposed organic material available in humid locations of the globe called Peat moss mines. This material used separately or mixed with other substrates such as vermiculite or sand.

The peat moss characterized by the following:



#### *6.3.1.2. Rice husk* The Peat moss considered the most common substrate and widely used at global level. It is a decomposed Provides necessary aeration for roots of different plants. If mixed with a substrate of bad aeration, it can improve airing and drainage capacity.

The substrate should be free from different pests and insects so that it would not form a source of

In case of using organic medium, it would preferably be of slow deteriorating nature so that it continues to be in the best condition for the longest period possible. This will reduce the cost of changing the substrate

The substrate should be free from different pests and insects so that it would not form a source of

The substrate should be free from salinity to avoid affecting the growing plants. For instance, the medium made of wood dust usually contains high concentration of sodium chloride due to soaking the wood

This is to avoid being a source of weeds, which will grow and compete with the main crop for nutrition and water. In many cases, weeds would also be a host for some diseases, which would infect and damage the

The substrate should be free from salinity to avoid affecting the growing plants. For instance, the medium made of wood dust usually contains high concentration of sodium chloride due to soaking the wood

There are many kinds of substrates but it is important that the selected one be available in several locations to facilitate its handling and transportation. This would result in reducing the cost of transportation and hence, the preliminary cost of establishing the roof garden. The price of the substrates should be

This is to avoid being a source of weeds, which will grow and compete with the main crop for nutrition and water. In many cases, weeds would also be a host for some diseases, which would infect and damage the

**Inert media:** A solid inert material for supporting the plant and provides air and water availability

**Organic media:** A natural organic material for supporting the plant such as peat moss, coconut fibers,

In case of using organic medium, it would preferably be of slow deteriorating nature so that it continues to be in the best condition for the longest period possible. This will reduce the cost of changing the substrate

There are several raw materials, which used as substrates for roof farming. Such materials differ from

one another about its physical characteristics. Due to variations and multiplicity in the forms and types of materials available in the surrounding environment, there is a need for particular criteria, which enables us to select

There are many kinds of substrates but it is important that the selected one be available in several locations to facilitate its handling and transportation. This would result in reducing the cost of transportation and hence, the preliminary cost of establishing the roof garden. The price of the substrates should be

The Peat moss considered the most common substrate and widely used at global level. It is a decomposed organic material available in humid locations of the globe called Peat moss mines. This material used separately or

**To be free from diseases incitements**

**To be slow in the decomposition process**

**The substrate should be free from weed seeds**

**To be free from diseases incitements**

infecting plants by different diseases.

**To be free from salinity**

in salt solution for long periods.

**The substrate should be free from weed seeds**

**To be easily transported, handled, and less expensive**

**To be slow in the decomposition process**

Growing media "substrates" can classified as follows:

Growing media "substrates" can classified as follows:

The peat moss characterized by the following:

level and drains surplus water.

mixed with other substrates such as vermiculite or sand.

the appropriate material for an agricultural medium (substrate).

High percentage of organic matter (94-99%).

**To be easily transported, handled, and less expensive**

the appropriate material for an agricultural medium (substrate).

appropriate and acceptable so that the system adopted by all categories of the society.

appropriate and acceptable so that the system adopted by all categories of the society.

conditions to the roots such as perlite, sand, Rockwool, volcanic gravel, pumice…etc.

conditions to the roots such as perlite, sand, Rockwool, volcanic gravel, pumice…etc.

Large capacity to absorb water about 8 folds of its weight at saturation

 Provides necessary aeration for roots of different plants. If mixed with a substrate of bad aeration, it can improve airing and drainage capacity.

infecting plants by different diseases.

**To be free from salinity**

in salt solution for long periods.

coco peat, rice hush, wood bark…etc.

growing plants.

**6.3 Types of growing media**

growing plants.

annually.

**6.3 Types of growing media**

**6.3.1 Organic substrates**

**6.3.1 Organic substrates**

Very light weight.

Low acidity level.

Very light weight.

High porosity (95-98%)

**6.3.1.1 Peat moss**

**6.3.1.2 Rice husk**

**6.3.1.2 Rice husk**

fruits.

**6.3.1.3 Coconut fibers**

**6.3.1.3 Coconut fibers**

fruits.

coco peat, rice hush, wood bark…etc.

High porosity (95-98%)

Low acidity level.

The peat moss characterized by the following:

The characteristics of rice husk presented below:

level and drains surplus water.

Has a medium capacity to hold water.

The characteristics of rice husk presented below:

Has a medium capacity to hold water.

High percentage of organic matter (94-99%).

annually.

**6.3.1.1 Peat moss**

This is to avoid being a source of weeds, which will grow and compete with the main crop for nutrition and water. In many cases, weeds would also be a host for some diseases, which would

In case of using organic medium, it would preferably be of slow deteriorating nature so that it continues to be in the best condition for the longest period possible. This will reduce the cost

There are many kinds of substrates but it is important that the selected one be available in several locations to facilitate its handling and transportation. This would result in reducing the cost of transportation and hence, the preliminary cost of establishing the roof garden. The price of the substrates should be appropriate and acceptable so that the system adopted by all

**Inert media:** A solid inert material for supporting the plant and provides air and water availability conditions to the roots such as perlite, sand, Rockwool, volcanic gravel, pum‐

**Organic media:** A natural organic material for supporting the plant such as peat moss, coconut

There are several raw materials, which used as substrates for roof farming. Such materials differ from one another about its physical characteristics. Due to variations and multiplicity in the forms and types of materials available in the surrounding environment, there is a need for particular criteria, which enables us to select the appropriate material for an agricultural

The Peat moss considered the most common substrate and widely used at global level. It is a decomposed organic material available in humid locations of the globe called Peat moss mines. This material used separately or mixed with other substrates such as vermiculite or sand.

**•** Large capacity to absorb water about 8 folds of its weight at saturation level and drains

infect and damage the growing plants [1]. **•** To be slow in the decomposition process

of changing the substrate annually [1].

categories of the society [1].

**6.3. Types of growing media**

medium (substrate) [9].

*6.3.1. Organic substrates*

*6.3.1.1. Peat moss*

surplus water.

**•** Low acidity level.

ice...etc.

**•** To be easily transported, handled, and less expensive

78 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

Growing media "substrates" can classified as follows:

fibers, coco peat, rice hush, wood bark...etc.

The peat moss characterized by the following:

The characteristics of rice husk presented below: organic material available in humid locations of the globe called Peat moss mines. This material used separately or mixed with other substrates such as vermiculite or sand.


#### The coconut peat and fibers have recently used as substrate for soil-less agriculture. It obtained from the coconut *6.3.1.3. Coconut fibers*

The coconut peat and fibers have recently used as substrate for soil-less agriculture. It obtained from the coconut fruits.

#### **Characteristics of coconut fibers**:


#### *6.3.2. Non-organic substrates*

#### Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate *6.3.2.1. Sand*

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

**6.3.2.1 Sand**

or compost.

**6.3.2.2 Vermiculite**

**6.3.2.1 Sand**

or compost.

**6.3.2.2 Vermiculite**

**6.3.2.3 Perlite**

characteristics appropriate to soil-less agriculture.

more appropriate for plant growth.

characteristics appropriate to soil-less agriculture.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Perlite are:**

elements needed by the plants. A substrate of good airing conditions.

more appropriate for plant growth.

sub-surface method.

**Some characteristics of Perlite are:**

elements needed by the plants. A substrate of good airing conditions.

sub-surface method.

alternation. A light weight material.

plants.

alternation. A light weight material.

plants.

**6.3.2.3 Perlite**

physical characteristics.

Has capacity to hold water.

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

physical characteristics.

Has capacity to hold water.

Can provide enough airing to the substrate.

Can provide enough airing to the substrate.

Possibility of use for more than one year without any change in its

Its decomposition slow therefore, it would not deteriorate quickly.

Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss

Contains magnesium and potassium in an absorbable form for the

material and therefore, continues to be wet most of time; hence, it is

A material of stable physical consistence with no capacity of cationic

 Contains magnesium and potassium in an absorbable form for the benefit of plants. It has noted that vermiculite is a good water absorption material and therefore, continues to be wet most of time; hence, it is

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

A material of good capillary porosity which facilitates its irrigation by

Perlite is widely used either separately with good results or in a mix with

A material of stable physical consistence with no capacity of cationic

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

A material of good capillary porosity which facilitates its irrigation by

Perlite is widely used either separately with good results or in a mix with

of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss or compost. Possibility of use for more than one year without any change in its Its decomposition slow therefore, it would not deteriorate quickly.

#### benefit of plants. It has noted that vermiculite is a good water absorption *6.3.2.2. Vermiculite*

Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000C. This results to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules.

other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental

other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental

This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000C. This results to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules.

preferable to mix it with other materials to reduce such permanent wet condition so that it would be

preferable to mix it with other materials to reduce such permanent wet condition so that it would be This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and characteristics appropriate to soil-less agriculture.

preferable to mix it with other materials to reduce such permanent wet condition so that it would be Some characteristics of Vermiculite are:


#### *6.3.2.3. Perlite*

It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

**6.3.2.1 Sand**

or compost.

**6.3.2.2 Vermiculite**

**6.3.2.1 Sand**

or compost.

**6.3.2.2 Vermiculite**

**6.3.2.3 Perlite**

characteristics appropriate to soil-less agriculture.

more appropriate for plant growth.

characteristics appropriate to soil-less agriculture.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Perlite are:**

elements needed by the plants. A substrate of good airing conditions.

more appropriate for plant growth.

sub-surface method.

**Some characteristics of Perlite are:**

elements needed by the plants. A substrate of good airing conditions.

sub-surface method.

alternation. A light weight material.

plants.

alternation. A light weight material.

plants.

**6.3.2.3 Perlite**

physical characteristics.

Has capacity to hold water.

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

physical characteristics.

Has capacity to hold water.

Can provide enough airing to the substrate.

Can provide enough airing to the substrate.

Possibility of use for more than one year without any change in its

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss

Possibility of use for more than one year without any change in its

Its decomposition slow therefore, it would not deteriorate quickly.

Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss

 Contains magnesium and potassium in an absorbable form for the benefit of plants. It has noted that vermiculite is a good water absorption material and therefore, continues to be wet most of time; hence, it is

Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and

A material of stable physical consistence with no capacity of cationic

 Contains magnesium and potassium in an absorbable form for the benefit of plants. It has noted that vermiculite is a good water absorption material and therefore, continues to be wet most of time; hence, it is

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

A material of good capillary porosity which facilitates its irrigation by

Perlite is widely used either separately with good results or in a mix with

A material of stable physical consistence with no capacity of cationic

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

A material of good capillary porosity which facilitates its irrigation by

Perlite is widely used either separately with good results or in a mix with

It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in

*6.3.2. Non-organic substrates*

80 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

**6.3.2.1 Sand**

or compost.

**6.3.2.1 Sand**

**6.3.2.2 Vermiculite**

or compost.

**6.3.2.2 Vermiculite**

**6.3.2.3 Perlite**

**6.3.2.3 Perlite**

characteristics appropriate to soil-less agriculture.

more appropriate for plant growth.

more appropriate for plant growth.

characteristics appropriate to soil-less agriculture.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Vermiculite are:**  High capacity to hold water.

**Some characteristics of Perlite are:**

elements needed by the plants. A substrate of good airing conditions.

elements needed by the plants. A substrate of good airing conditions.

sub-surface method.

sub-surface method.

alternation. A light weight material.

**Some characteristics of Perlite are:**

alternation. A light weight material.

plants.

physical characteristics.

Has capacity to hold water.

**Characteristics of coconut fibers:**

**6.3.2 Non-organic substrates**

physical characteristics.

Has capacity to hold water.

Can provide enough airing to the substrate.

Can provide enough airing to the substrate.

Possibility of use for more than one year without any change in its

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss

Its decomposition slow therefore, it would not deteriorate quickly.

Possibility of use for more than one year without any change in its

Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and

Sand considered one of the best and oldest materials used as a solid substrate for growing plants. It is preferable not to use sands containing lime due to the high rate of calcium carbonate, which acts as a welding material for sand granules and changes the physical characteristics of sand. It is also advisable not to use coast sands due to its high content of salt. It is preferable to use sands of granite or silicone origin as agriculture substrate. The diameter of sand granules is an important factor for successful preparation of agriculture substrate with sand. The course sand cannot hold enough quantity of moisture and very fine sand does not allow a sufficient rate of aeration. Sand characterized by good drainage capacity but its ability to hold water is weak. Therefore, it is preferable to mix it with peat moss

 Contains magnesium and potassium in an absorbable form for the benefit of plants. It has noted that vermiculite is a good water absorption material and therefore, continues to be wet most of time; hence, it is

Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules.

A material of good capillary porosity which facilitates its irrigation by

A material of stable physical consistence with no capacity of cationic

Perlite is widely used either separately with good results or in a mix with

 Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional

A material of good capillary porosity which facilitates its irrigation by

Perlite is widely used either separately with good results or in a mix with

Its decomposition slow therefore, it would not deteriorate quickly.

to hold water is weak. Therefore, it is preferable to mix it with peat moss or compost.

It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in Africa, Australia, and America. The material to use as a substrate obtained by treating the raw element with a temperature of 1000 centigrade. Therefore, the humidity transforms to vapor which creates an increasing pressure inside its layers, which in turn fragmented to small light pieces of good porosity and characteristics appropriate to soil-less

*6.3.2.1. Sand*

preferable to mix it with other materials to reduce such permanent wet condition so that it would be

agriculture.

*6.3.2.2. Vermiculite*

other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental

other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental

This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000C. This results to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules.

preferable to mix it with other materials to reduce such permanent wet condition so that it would be

This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000C. This results to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules.

It is dehydrated iron, aluminum and magnesium silicate, which obtained from metallic chips from Mica mines in

Its decomposition slow therefore, it would not deteriorate quickly.

 A material of stable physical consistence with no capacity of cationic This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000°C. This results to swelling due to exodus of hot air forming air gaps, which cause large expansion, and swelling of granules. This is a volcanic stone originated from volcanic lava of color graded from grey to white and consist of Aluminum Silicate + Sodium and Potassium, which is grinded and heated to high temperature from 900-1000C. This results

other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental plants. Some characteristics of Perlite are:


#### *6.3.2.4. Calcined or Expanded clays*

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

The pottery-like particles formed are six times as heavy as perlite.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

This material is a very durable and useful amendment [11].

#### It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. *6.3.2.5. Pumice*

 Pumice a material similar to Perlite from the chemical point except that it contain calcium carbonate which make a problem which react with acid leading to a reduction in the size of the particle. This

This is a silicon rock of volcanic origin, contains Aluminum, Potassium, Sodium, traces of Iron, Calcium, and Magnesium. The material has several gaps, which formed because of hot vapor exodus before the volcanic

The use of rockwool has quickly spread in agriculture particularly in Europe where it used to produce many

It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and Coal (20%).

This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed

reduction of particle after using for longer time, the substrate can be compacted. It differ than perlite in physical characteristics, where this material is heavier.

Does not absorb water easily and does not hold it for a long period.

lava cools down. This material is available in its natural form and does not need

 Foamy rock is a material similar to Perlite from the chemical point of view but differs in physical characteristics, as the first material is heavier.

Does not absorb water easily and doesn't hold it for a long period.

heating but only breaking and grinding to the appropriate size of granules.

**6.3.2.4 Calcined or Expanded clays**

**6.3.2.5 Pumice**

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

The pottery-like particles formed are six times as heavy as perlite.

This material is a very durable and useful amendment.

Pumice is direct product of acidic volcanism.

from the vesicular nature of this rock.

A substrate of good airing condition.

Easy to clean and purify.

**Some characteristics of Foamy rock are:**

Easy to clean and purify.

vegetable and ornamental crops.

A substrate of good airing condition.

Some characteristics of pumice

**6.3.2.6 Foamy rock**

**6.3.2.7 Rockwool**

The vesicles are glass–walled bubble casts, which give pumice a low density compared to natural glass. Pumicite, the commercial term for fine-grained , fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-to-weight ratio, insulation and high surface area, which result **Pumice** Pumice is direct product of acidic volcanism. It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low density compared to natural glass. Pumicite, the commercial term for fine-grained, fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-toweight ratio, insulation and high surface area, which result from the vesicular nature of this rock [11].

**Expanded Clay**

Some characteristics of pumice

**•** Good drainage capacity while holding enough water. However, irrigation is preferred several times per day to guarantee the water and nutritional elements needed by the plants.

**6.3.2.4 Calcined or Expanded clays**

**6.3.2.5 Pumice**

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

density compared to natural glass. Pumicite, the commercial term for fine-grained , fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-to-weight ratio, insulation and high surface area, which result

The pottery-like particles formed are six times as heavy as perlite.

It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low

This material is a very durable and useful amendment.

Pumice is direct product of acidic volcanism.

from the vesicular nature of this rock.

A substrate of good airing condition.

Easy to clean and purify.

**Some characteristics of Foamy rock are:**

Easy to clean and purify.

vegetable and ornamental crops.

A substrate of good airing condition.

Some characteristics of pumice

**6.3.2.6 Foamy rock**

**6.3.2.7 Rockwool**

**•** A material of good capillary porosity which facilitates its irrigation by sub-surface method.

**•** Perlite is widely used either separately with good results or in a mix with other substrates like peat moss to grow several vegetable crops, seeds, flowers, and indoor ornamental

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

**Expanded Clay**

Pumice is direct product of acidic volcanism. It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low density compared to natural glass. Pumicite, the commercial term for fine-grained, fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-toweight ratio, insulation and high surface area, which result from the vesicular nature of this

**Pumice**

The pottery-like particles formed are six times as heavy as perlite.

82 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

This material is a very durable and useful amendment [11].

**•** A substrate of good airing conditions.

*6.3.2.4. Calcined or Expanded clays*

plants.

*6.3.2.5. Pumice*

rock [11].

**6.3.2.4 Calcined or Expanded clays**

**6.3.2.5 Pumice**

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

density compared to natural glass. Pumicite, the commercial term for fine-grained , fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-to-weight ratio, insulation and high surface area, which result

 Pumice a material similar to Perlite from the chemical point except that it contain calcium carbonate which make a problem which react with acid leading to a reduction in the size of the particle. This

This is a silicon rock of volcanic origin, contains Aluminum, Potassium, Sodium, traces of Iron, Calcium, and Magnesium. The material has several gaps, which formed because of hot vapor exodus before the volcanic

The use of rockwool has quickly spread in agriculture particularly in Europe where it used to produce many

It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and Coal (20%).

This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed

reduction of particle after using for longer time, the substrate can be compacted. It differ than perlite in physical characteristics, where this material is heavier.

Does not absorb water easily and does not hold it for a long period.

lava cools down. This material is available in its natural form and does not need

 Foamy rock is a material similar to Perlite from the chemical point of view but differs in physical characteristics, as the first material is heavier.

Does not absorb water easily and doesn't hold it for a long period.

heating but only breaking and grinding to the appropriate size of granules.

The pottery-like particles formed are six times as heavy as perlite.

It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low

This material is a very durable and useful amendment.

Pumice is direct product of acidic volcanism.

from the vesicular nature of this rock.

A substrate of good airing condition.

Easy to clean and purify.

**Some characteristics of Foamy rock are:**

Easy to clean and purify.

vegetable and ornamental crops.

A substrate of good airing condition.

Some characteristics of pumice

**6.3.2.6 Foamy rock**

**6.3.2.7 Rockwool**

	- **•** It differ than perlite in physical characteristics, where this material is heavier.
	- **•** Does not absorb water easily and does not hold it for a long period.

#### *6.3.2.6. Foamy rock*

 Foamy rock is a material similar to Perlite from the chemical point of view but differs in physical characteristics, as the first material is heavier. Does not absorb water easily and doesn't hold it for a long period. This is a silicon rock of volcanic origin, contains Aluminum, Potassium, Sodium, traces of Iron, Calcium, and Magnesium. The material has several gaps, which formed because of hot vapor exodus before the volcanic lava cools down. This material is available in its natural form and does not need heating but only breaking and grinding to the appropriate size of granules.

Some characteristics of Foamy rock are:


This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed

**Expanded Clay**

**Pumice**

#### *6.3.2.7. Rockwool*

 Pumice a material similar to Perlite from the chemical point except that it contain calcium carbonate which make a problem which react with acid leading to a reduction in the size of the particle. This

This is a silicon rock of volcanic origin, contains Aluminum, Potassium, Sodium, traces of Iron, Calcium, and Magnesium. The material has several gaps, which formed because of hot vapor exodus before the volcanic

reduction of particle after using for longer time, the substrate can be compacted. It differ than perlite in physical characteristics, where this material is heavier.

Does not absorb water easily and does not hold it for a long period.

lava cools down. This material is available in its natural form and does not need

 Foamy rock is a material similar to Perlite from the chemical point of view but differs in physical characteristics, as the first material is heavier.

Does not absorb water easily and doesn't hold it for a long period.

heating but only breaking and grinding to the appropriate size of granules.

**6.3.2.4 Calcined or Expanded clays**

**6.3.2.5 Pumice**

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

density compared to natural glass. Pumicite, the commercial term for fine-grained , fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-to-weight ratio, insulation and high surface area, which result

The pottery-like particles formed are six times as heavy as perlite.

It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low

This material is a very durable and useful amendment.

Pumice is direct product of acidic volcanism.

from the vesicular nature of this rock.

A substrate of good airing condition.

Easy to clean and purify.

**Some characteristics of Foamy rock are:**

Easy to clean and purify.

vegetable and ornamental crops.

A substrate of good airing condition.

Some characteristics of pumice

**6.3.2.6 Foamy rock**

**6.3.2.7 Rockwool**

The use of rockwool has quickly spread in agriculture particularly in Europe where it used to produce many vegetable and ornamental crops. The use of rockwool has quickly spread in agriculture particularly in Europe where it used to produce many

It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and Coal (20%). It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and Coal (20%).

This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed and divided into the required sizes. During the cooling process, the phenol material added to help sticking the rocky wool into a substrate of good porosity. This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed

#### **Important forms and uses of rockwool**


#### **Some characteristics of rockwool are:**


**•** Easy to sterilize and could be used for more than a year.

and divided into the required sizes. During the cooling process, the phenol material added to help sticking the

rocky wool into a substrate of good porosity. **Important forms and uses of rockwool** 

where plant completes its life cycle.

characteristics of airing and water holding.

 Sterilized material free of pests, insects, and disease. Very light but solid material. This facilitates its preparation and

form.

directly.

solution.

processing.

**6.4 Substrates Mixtures**

Substrate's weight

Degree of stability

Acidity (PH)

summarized below:

facilitates drainage.

in the open system for leaching.

*Some characteristics of rockwool are:*

**Germination cubes**: This could be in a single or aggregated

 **Seedlings blocks**: To accommodate the small germination cubic's with its contents of plants or the young seedlings

 **Loose (unpacked) rock wool**: This used as substrates for cultivation in pots or mixed with other substrates to improve the

**Agricultural slices**: To which seeds of proper size transferred,

Dry material does not contain any nutritional or non-nutritional

A material of high porosity (97% of the total size) which

Facilitates disposal of salt sediments through adding water only

The above substrates used separately or in the form of mixture of more than one substrate.

Easy to sterilize and could be used for more than a year.

together to attain the best characteristic for the plants to be grown.

The above substrates used separately or in the form of mixture of more than one substrate.

#### The above-mentioned substrates could be used in a separate form as agricultural substrate or may be mixed **6.4. Substrates mixtures**

*6.3.2.7. Rockwool*

 Pumice a material similar to Perlite from the chemical point except that it contain calcium carbonate which make a problem which react with acid leading to a reduction in the size of the particle. This

This is a silicon rock of volcanic origin, contains Aluminum, Potassium, Sodium, traces of Iron, Calcium, and Magnesium. The material has several gaps, which formed because of hot vapor exodus before the volcanic

reduction of particle after using for longer time, the substrate can be compacted. It differ than perlite in physical characteristics, where this material is heavier.

Does not absorb water easily and does not hold it for a long period.

lava cools down. This material is available in its natural form and does not need

 Foamy rock is a material similar to Perlite from the chemical point of view but differs in physical characteristics, as the first material is heavier.

Does not absorb water easily and doesn't hold it for a long period.

heating but only breaking and grinding to the appropriate size of granules.

**6.3.2.4 Calcined or Expanded clays**

**6.3.2.5 Pumice**

Heating montmorrillonitic clay minerals to approximately 690ºC forms calcined clays.

Calcined clays have a relatively high cation exchange as well as water holding capacity.

density compared to natural glass. Pumicite, the commercial term for fine-grained , fragmented pumice with shards under 2mm in diameter, may be deposited some distance from the source. Pumice is formed from silicic lavas rich in dissolved volatiles, particularly water vapor. On eruption, sudden release of pressure leads to expansion of volatile which, in turn, generates a frothy mass of expelled lava. This mass may solidify on contact with the atmosphere as a vent filling or flow, or may be shattered by a violent eruption. Pumice has many advantages such as high strength-to-weight ratio, insulation and high surface area, which result

The pottery-like particles formed are six times as heavy as perlite.

It is a highly vesicular volcanic glass, silicic in composition and occurs as massive blocks or unconsolidated, fragmented material. The vesicles are glass–walled bubble casts, which give pumice a low

This material is a very durable and useful amendment.

Pumice is direct product of acidic volcanism.

from the vesicular nature of this rock.

A substrate of good airing condition.

Easy to clean and purify.

**Some characteristics of Foamy rock are:**

Easy to clean and purify.

vegetable and ornamental crops.

A substrate of good airing condition.

Some characteristics of pumice

**6.3.2.6 Foamy rock**

**6.3.2.7 Rockwool**

Coal (20%).

The use of rockwool has quickly spread in agriculture particularly in Europe where it used to produce many

It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and Coal (20%).

This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed

good porosity.

cycle.

leaching.

produce many vegetable and ornamental crops.

84 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

**Important forms and uses of rockwool**

or the young seedlings directly.

**Some characteristics of rockwool are:**

**•** Sterilized material free of pests, insects, and disease.

**• Germination cubes**: This could be in a single or aggregated form.

The use of rockwool has quickly spread in agriculture particularly in Europe where it used to

**Expanded Clay**

**Pumice**

It is a fiber produced from volcanic rocks and contains Diabase (60%), Lime stone (20%) and

This mix heated to very high temperature for melting together. The melted material is transformed to fine threads of 5-micron diameter after treatment with fast centrifugal machine and cooling. The threads are then compressed and divided into the required sizes. During the cooling process, the phenol material added to help sticking the rocky wool into a substrate of

**• Seedlings blocks**: To accommodate the small germination cubic's with its contents of plants

**• Agricultural slices**: To which seeds of proper size transferred, where plant completes its life

**• Loose (unpacked) rock wool**: This used as substrates for cultivation in pots or mixed with

**•** Facilitates disposal of salt sediments through adding water only in the open system for

other substrates to improve the characteristics of airing and water holding.

**•** Dry material does not contain any nutritional or non-nutritional solution.

**•** Very light but solid material. This facilitates its preparation and processing.

**•** A material of high porosity (97% of the total size) which facilitates drainage.

The substrate characteristic has a strong impact on success of agricultural operation because it determines the balance between water needed for plant growth and the air necessary for root's breathing. It is therefore, necessary to have small gaps to help holding of water needed for plant life and large gaps required to ensure air necessary for its growth. Some of the most important characteristics, which assessed, are: The above-mentioned substrates could be used in a separate form as agricultural substrate or may be mixed together to attain the best characteristic for the plants to be grown.

 Capacity to hold water Concentration of salts Apparent density of substrate Cation exchange capacity The above characteristics show the importance of mixing more than one substrates together to achieve the The substrate characteristic has a strong impact on success of agricultural operation because it determines the balance between water needed for plant growth and the air necessary for root's breathing. It is therefore, necessary to have small gaps to help holding of water needed for plant life and large gaps required to ensure air necessary for its growth. Some of the most important characteristics, which assessed, are:

> 2:2:1 1:1 1:3 3:1 1:3 1:4

	- Peat moss: Perlite: sand Peat moss: Perlite **•** Acidity (PH)
	- Peat moss: sand Peat moss: sand Peat moss: vermiculite **•** Concentration of salts
		- Peat moss: perlite **•** Apparent density of substrate
			- **•** Cation exchange capacity
			- **•** Degree of stability

The above characteristics show the importance of mixing more than one substrates together to achieve the required mixtures. Some of such mixtures were tested and showed good results. Ratios of some mixtures summarized below:

**Figure 4.** Cucumber grown in sand culture under green house


**Table 1.** Some substrates mixtures. [9]

#### **7. The Recommended substrate system in arid lands**

#### **7.1. Sand culture in Egypt**

[4] had design a sand culture under plastic tunnels at Dokki Protected Cultivation Center, Cairo.

The design was as follow:

Five 0.8 \* 38rn trenches for each tunnel were excavated to a depth of 20 or 40 cm. The bottom of each trench was first leveled and graded to a slope of 12 cm per 40m [5]. The profile of the trench was adjusted to 1 (V) shape. The trench was lined with a water proof polyethylene sheet (200 p) to prevent plants from rooting into the original soil [6]. The surface of the bed was sloped to be parallel to the bottom of the trench.

There inches corrugated perforated plastic pipe placed along the bottom of each trench. The drains were connected at the lower end to a main drain that sink into a 9 m3 nutrient tank. Once the drain pipes are in place, washed coarse sand obtained from Cairo - Alex. Desert road (km 40) filled to a depth of either 20 or 40 cm.

The nutrient tank was 2.0 m length X 1.5 m width X 3.0 m height with 30 cm thick concrete construction, coated with bituminous paint. This tank divided into two equal parts each designed to hold a volume of 30 to 40 % greater than maximum volume required for daily irrigation of each tunnel [10]. A float valve attached to a water refilling line in order to maintain the water level in the tank. The system is designed to recirculate the nutrient solution fre‐ quently from the nutrient tank by means of a submersible pump (1 Hp, 220V, and 2 inch in diameter outlet pipe) that was operated by a time clock, one or two times daily.

Some solid particles could be released into the recirculating solution, therefore filtration would be necessary. In fact, the tank acts as a sedimentation tank for the solid particles, which released from the main underground water supply or from recirculated nutrient solution. In addition, two filtration systems were used:


The filtration units particularly the screen filter have to be cleaned and replaced fairly frequently because solid particles retained on the screen will progressively reduce the flow rate through the screen.

A drip irrigation system was used with this sand culture [7] with excess nutrient solution (over 50 % of the total applied) to maintain recycling. Such system is termed as a closed system. The drip irrigation system feeds each plant individually by the use of two-liter emitter.

Drip irrigation system of each plastic tunnel contains 50 mm in diameter polyethylene header line. From this header line, 18 mm polyethylene pipe run along each plant row. The emitters were placed in these lateral lies at the base of each plant (50 cm distance between successive plants).

It is worthily to mention that, emitters, pipes fittings of drip irrigation system used for both soil or sand culture and the cover of nutrient tank should be black to prevent algae growth inside the piping system or the nutrient tank.

It is essential that materials used to construct the closed sand culture should not be phytotoxic. In other words, they should not have any harmful effect on the plants. No phytotoxicity has been reported from the use of concrete, bituminous pipes or sheets [5].

#### **7.2. Polystyrene pot system**

**Substrates Rate of mixing**

Peat moss: Perlite: sand 2:2:1 Peat moss: Perlite 1:1 Peat moss: sand 1:3 Peat moss: sand 3:1 Peat moss: vermiculite 1:3 Peat moss: perlite 1:4

[4] had design a sand culture under plastic tunnels at Dokki Protected Cultivation Center,

Five 0.8 \* 38rn trenches for each tunnel were excavated to a depth of 20 or 40 cm. The bottom of each trench was first leveled and graded to a slope of 12 cm per 40m [5]. The profile of the trench was adjusted to 1 (V) shape. The trench was lined with a water proof polyethylene sheet (200 p) to prevent plants from rooting into the original soil [6]. The surface of the bed was

**Table 1.** Some substrates mixtures. [9]

**Figure 4.** Cucumber grown in sand culture under green house

86 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

**7.1. Sand culture in Egypt**

The design was as follow:

sloped to be parallel to the bottom of the trench.

Cairo.

**7. The Recommended substrate system in arid lands**

There are two main systems for the polystyrene pot system:

**Figure 5.** Vertical pot system (Condensing system)

#### *7.2.1. Vertical pot system (Condensing system):*

Different production systems for different crops introduced to small growers in the APRP region by ICARDA-APRP. For production of cash crops such as strawberries and beans, the vertical soilless production system was adapted to maximize growing space by growing the crops vertically. Such technique for strawberry has been investigated for last four years in Bahrain, Kuwait, Oman and Saudi Arabia and currently in Egypt has proved promising from the view point of productivity, cost and water saving. The fundamental structure of the system is the columns, which consist of 8-12 growing containers made from polystyrene on top of each other as seen in the photo. These column of polystyrene pots installed in sloped channel lined by polyethylene sheets to collect the excess of nutrient solution. At the end of the channels there is a PVC tube to collect the return nutrient solution delivering them to filter then to the nutrient solution tank. The column supported by one inch PVC tube from inside the pots. The pots filled substrate (peat moss: perlite 1:4 v/v). The crops are planted in the 4 corners of these containers. The irrigation water and nutrition solution applied to the plants using the drip irrigation and the excess of irrigation recirculated in closed system. The growing containers made locally and the system could be installed in any greenhouse or even in the open field.

#### Main advantages of the system

The production of strawberries in the vertical hydroponics system was quite successful. The hydroponics system showed followings advantage over the traditional soil-bed production system:

**1.** 30-50% savings in the cost of the production materials;


#### *7.2.2. Simple pot system*

*7.2.1. Vertical pot system (Condensing system):*

88 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

**Figure 5.** Vertical pot system (Condensing system)

Main advantages of the system

**1.** 30-50% savings in the cost of the production materials;

system:

Different production systems for different crops introduced to small growers in the APRP region by ICARDA-APRP. For production of cash crops such as strawberries and beans, the vertical soilless production system was adapted to maximize growing space by growing the crops vertically. Such technique for strawberry has been investigated for last four years in Bahrain, Kuwait, Oman and Saudi Arabia and currently in Egypt has proved promising from the view point of productivity, cost and water saving. The fundamental structure of the system is the columns, which consist of 8-12 growing containers made from polystyrene on top of each other as seen in the photo. These column of polystyrene pots installed in sloped channel lined by polyethylene sheets to collect the excess of nutrient solution. At the end of the channels there is a PVC tube to collect the return nutrient solution delivering them to filter then to the nutrient solution tank. The column supported by one inch PVC tube from inside the pots. The pots filled substrate (peat moss: perlite 1:4 v/v). The crops are planted in the 4 corners of these containers. The irrigation water and nutrition solution applied to the plants using the drip irrigation and the excess of irrigation recirculated in closed system. The growing containers made locally and the system could be installed in any greenhouse or even in the open field.

The production of strawberries in the vertical hydroponics system was quite successful. The hydroponics system showed followings advantage over the traditional soil-bed production For production of cash crops such as tomato, pepper, cantaloupe...etc, the recirculation pot system adapted to maximize growing space by growing the crops in polystyrene pots. Such technique for the cash crops has been investigated for last four years in Bahrain, Kuwait, Oman and Saudi Arabia and currently in Egypt has proved promising from the view point of productivity, cost and water saving. The fundamental structure of the system is simple containers made from polystyrene inserted in a sloped channel lined by polyethylene as seen in the photo. The crops are planted in these containers in substrate consists of perlite: peat moss (4:1 v/v). The irrigation water and nutrition solution applied to the plants using the drip irrigation and the excess of irrigation recirculated in closed system.

**Figure 6.** Simple pot system cultivated with tomato seedlings

**Figure 7.** Simple pot system cultivated with cucumber

#### **7.3. Polyethylene containers**

There are different types of containers is suitable to substrate culture in arid lands. Also, the different containers shapes create different substrate systems as follow:

#### *7.3.1. Open toped container (Vertical containers)*

This type of containers suitable for substrate can hold the water because it can allow a longer column of substrate for the big plants and allowed the water to be drained by gravity.

The idea for these containers to have a holes at the lowermost of the container (5 cm from the bottom) to allow the water to drain. The container filled with small gravel in these 5 cm and then by the chosen substrate. If the open system is used, the containers installed on a bed covered by polyethylene sheets and the drain water is collected and used in another use. If the closed system is used, there a gutter is installed and the containers are installed inside these gutter. The drain water collected and delivered to the nutrient solution after filtering to the nutrient solution tank.

#### *7.3.2. Horizontal bags*

The idea of these bags is use for the substrate cannot hold the water like perlite. These bags have a short side and there are holes at the lowermost to drain the excess water. When these bags filled with water, part of these holes will be blocked and keep some water at the bottom of the bags to be a pool can supply the roots with water and nutrient.

There are different types of containers is suitable to substrate culture in arid lands. Also, the different

This type of containers suitable for substrate can hold the water because it can allow a longer column of

The idea for these containers to have a holes at the lowermost of the container (5 cm from the bottom) to allow the water to drain. The container filled with small gravel in these 5 cm and then by the chosen substrate. If

allow the water to drain. The container filled with small gravel in these 5 cm and then by the chosen substrate. If

installed inside these gutter. The drain water collected and delivered to the nutrient solution after filtering to the

containers shapes create different substrate systems as follow:

substrate for the big plants and allowed the water to be drained by gravity.

**7.3.1 Open toped container (Vertical containers)**

**7.3 Polyethylene containers**

nutrient solution tank.

 **Photo (8) container system using polyethylene bags Photo (9) container system using polyethylene pots Figure 8.** Container system using polyethylene bags collected and used in another use. If the closed system is used, there a gutter is installed and the containers are installed inside these gutter. The drain water collected and delivered to the nutrient solution after filtering to the the open system is used, the containers installed on a bed covered by polyethylene sheets and the drain water is collected and used in another use. If the closed system is used, there a gutter is installed and the containers are

nutrient solution tank.

the open system is used, the containers installed on a bed covered by polyethylene sheets and the drain water is

**7.3 Polyethylene containers**

nutrient solution tank.

**7.3.1 Open toped container (Vertical containers)**

**Figure 7.** Simple pot system cultivated with cucumber

*7.3.1. Open toped container (Vertical containers)*

There are different types of containers is suitable to substrate culture in arid lands. Also, the

This type of containers suitable for substrate can hold the water because it can allow a longer column of substrate for the big plants and allowed the water to be drained by gravity.

The idea for these containers to have a holes at the lowermost of the container (5 cm from the bottom) to allow the water to drain. The container filled with small gravel in these 5 cm and then by the chosen substrate. If the open system is used, the containers installed on a bed covered by polyethylene sheets and the drain water is collected and used in another use. If the closed system is used, there a gutter is installed and the containers are installed inside these gutter. The drain water collected and delivered to the nutrient solution after filtering to the

The idea of these bags is use for the substrate cannot hold the water like perlite. These bags have a short side and there are holes at the lowermost to drain the excess water. When these bags filled with water, part of these holes will be blocked and keep some water at the bottom

different containers shapes create different substrate systems as follow:

90 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

of the bags to be a pool can supply the roots with water and nutrient.

**7.3. Polyethylene containers**

nutrient solution tank.

*7.3.2. Horizontal bags*

 **Photo (10) container system using polyethylene containers**

 **Photo (8) container system using polyethylene bags Photo (9) container system using polyethylene pots**

 **Photo (8) container system using polyethylene bags Photo (9) container system using polyethylene pots Figure 9.** Container system using polyethylene pots

**Figure 10. Photo (10** Container system using polyethylene containers **) container system using polyethylene containers**

**7.3.2 Horizontal bags** 

nutrient.

 The idea of these bags is use for the substrate cannot hold the water like perlite. These bags have a short side and there are holes at the lowermost to drain the excess water. When these bags filled with water, part of these holes will be blocked and keep some water at the bottom of the bags to be a pool can supply the roots with water and

**Figure 11.** Strawberry and sweet pepper cultivated in Horizontal bags

**8. Water quality control in the arid lands:** 

#### The limited water resources and rapid increase in population were the major factors that drew the attention towards the use of substrate in the arid lands. **8. Water quality control in the arid lands**

The limited water resources and rapid increase in population were the major factors that drew the attention towards the use of substrate in the arid lands.

 **Photo (11) strawberry and sweet pepper cultivated in Horizontal bags** 

The best water for substrate cropping is rainwater or water condensed from moisture - laden air. Water from these two sources has virtually no dissolved substances in it. Consequently, there is no build - up of excess ions coming into the substrate installation with the make - up water. An economy in the arid lands, the use of this scarce water can be obtained, if it is mixed with less pure water to provide a blended water in which the concentration of dissolved substances is still acceptable. If the water, that is being used has dissolved in it a substance that is being supplied by the make – up water at a faster than the crop is removing it, then an excess will accumulate in the recirculating solution. If the build - up of the excess is not too rapid, then it is quite realistic to pump out the nutrient solution from the installation after a period of time that was not sufficient duration for an adverse concentration to build up.

[2] suggested to obtain an analysis of the water supply in ppm for the following ions : nitrogen phosphorus,potassium calcium magnesium iron manganese boron, copper, molybdenum, zinc, sodium, chlorides and sulphate. From an inspection of the analytical data it should be possible to decide which ion, or ions, may build up to adversely high concentrations.

Arrangements should then be made for weekly analyses to enable the concentration of the suspect ion (or ions) to be plotted on a graph as the concentration build up. Close observation of the crop will indicate when appearance of the plants begins to be not quite right. However, this method is very - expensive.

On the other hand, [8] suggested a method for deciding when the nutrient solution can be discharging when the hard water was used. This method used successfully in Egypt when the ground water used in the substrate system.

The author suggested that the two most common salts dissolved in the hard water are calcium and magnesium. Electrical conductivity, monitored as EC increases as nutrient salts dissolved in the solution. It follows then that natural salts dissolved in water added to the EC. The EC of the water before nutrients added is known as the base EC. Use the conductivity meter to measure base EC taking care to use a representative sample, i.e., from a pond or other open water source. Collect from "open" water not from puddle edges, from the tap; run the tap for a minute before collecting the sample. If your CF meter is not 'temperature compensated adjust the sample temperature to around 20 "C before taking a reading. The author divided the water to:


#### **9. The conductivity program using hard water (Base EC 0.4 – 0.8 m.mhos)**

The sum of the effects of using hard water make - up supplies is that, after nutrients additions to a pre-determined level, desired EC subsequent changes in solution EC don't solely reflect the removal of nutrient from the solution by the plants. This situation manifests itself as stable solution EC when make - up water EC additions more or less equate with nutrient losses, or as rising solution EC when make - up water EC additions are greater than nutrient losses. Sometimes, the solution EC may fall if marginally hard water is used. Irrespective of the manifestation, the effect is a gradual decline of the nutrient status of the solution. This decline must be arrested and the following procedure demonstrates how this is done

#### **9.1. At system start - up**

**7.3.2 Horizontal bags** 

92 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

nutrient.

 The idea of these bags is use for the substrate cannot hold the water like perlite. These bags have a short side and there are holes at the lowermost to drain the excess water. When these bags filled with water, part of these holes will be blocked and keep some water at the bottom of the bags to be a pool can supply the roots with water and

 **Photo (11) strawberry and sweet pepper cultivated in Horizontal bags** 

of time that was not sufficient duration for an adverse concentration to build up.

possible to decide which ion, or ions, may build up to adversely high concentrations.

The limited water resources and rapid increase in population were the major factors that drew the attention

The limited water resources and rapid increase in population were the major factors that drew

The best water for substrate cropping is rainwater or water condensed from moisture - laden air. Water from these two sources has virtually no dissolved substances in it. Consequently, there is no build - up of excess ions coming into the substrate installation with the make - up water. An economy in the arid lands, the use of this scarce water can be obtained, if it is mixed with less pure water to provide a blended water in which the concentration of dissolved substances is still acceptable. If the water, that is being used has dissolved in it a substance that is being supplied by the make – up water at a faster than the crop is removing it, then an excess will accumulate in the recirculating solution. If the build - up of the excess is not too rapid, then it is quite realistic to pump out the nutrient solution from the installation after a period

[2] suggested to obtain an analysis of the water supply in ppm for the following ions : nitrogen phosphorus,potassium calcium magnesium iron manganese boron, copper, molybdenum, zinc, sodium, chlorides and sulphate. From an inspection of the analytical data it should be

Arrangements should then be made for weekly analyses to enable the concentration of the suspect ion (or ions) to be plotted on a graph as the concentration build up. Close observation of the crop will indicate when appearance of the plants begins to be not quite right. However,

**8. Water quality control in the arid lands:** 

**Figure 11.** Strawberry and sweet pepper cultivated in Horizontal bags

**8. Water quality control in the arid lands**

this method is very - expensive.

towards the use of substrate in the arid lands.

the attention towards the use of substrate in the arid lands.

Fill the nutrient solution tank with clean water, begin circulation and bring the system to operating capacity. Check, and note, the base CF of the water in the nutrient solution tank. Add the acid to reduce water pH close to desired pH "between 6 - 6.5". The amount of acid used will depend on the hardness of the water. It is useful to keep a record of the amount of acid required so that future treatment of the same volume, after solution discharges, will be rapidly accomplished. Do not overdose; avoid lowering the pH much below 6.0.

Determine desired EC depending on the crop and use the following equation:

Target EC = Desired EC + l/2 Base EC

Add nutrient stock solution A & B in equal volumes, unless specifically desired to do otherwise, to achieve target EC.

Add nutrient A first and allow this to disperse a little before adding B. Allow time between nutrient additions and monitoring EC for the nutrients to disperse throughout the system. This process may be encouraged by stirring the solution in the circulation tank. When target EC achieved check solution pH and adjust if necessary.

The following examples illustrate this procedure :


#### **9.2. Discharging the solution**

Eventually the target EC will be raised to an unacceptably high value. Generally, this occur‐ rence dictates the time the solution should discharged. The frequency of discharging will regulated by the rate of water removal by the plants of course, but also and particularly by the hardness, manifested as base EC of the make - up water.

The general advice, found to have great practical utility, is to allow the rise in EC to continue until it passes a value 50 % greater than the original EC. When it reaches this value you have to discharge the nutrient solution.

Some mono crop growers a dot the procedure of discharging the solution when the target EC reaches twice the desired EC.

#### **10. The special program for using very hard water (0.9 or above)**

The principal problems with very hard water supplies, base EC 0. 9 m.mhos or above, are these:

First, because of the very high level of natural salts present, there is a large oversupply of those which are also nutrient salts, so that a smaller proportion are removed from the system due to take up by the plants.

Second, large amounts of acid are required to neutralize the salts. The result is that' start - up solution EC, already high due to high base EC, is quickly increased by make - up water and acid additions, and there is reduced scope to assign these EC increases to useful nutrients. The practical significance is that the full base EC must be allowed at system start - up when calculating a target EC and when maintaining nutrient levels in the solution by setting a new target EC. Accordingly, when using very hard water supplies, calculation of target EC uses the following equation: time the solution should discharged. The frequency of discharging will regulated by the rate of water removal by the plants of course, but also and particularly by the hardness, manifested as base EC of the make - up water. The general advice, found to have great practical utility, is to allow the rise in EC to continue until it passes a value 50 % greater than the original EC. When it reaches this value you have to discharge the nutrient solution. Some mono crop growers a dot the procedure of discharging the solution when the target EC reaches twice the desired EC.

Eventually the target EC will be raised to an unacceptably high value. Generally, this occurrence dictates the

Target EC = Desired EC + Base EC **10. The special program for using very hard water (0.9 or above)**  The principal problems with very hard water supplies, base EC 0. 9 m.mhos or above, are these: -

Add nutrient A first and allow this to disperse a little before adding B. Allow time between nutrient additions and monitoring EC for the nutrients to disperse throughout the system. This process may be encouraged by stirring the solution in the circulation tank. When target EC

**•** Therefore, make - up water volume is 1/3 rd. of solution volume and contributes propor‐

**•** The new target EC = 1.4 m.mhos then add nutrients A & B to bring the solution to the new

Eventually the target EC will be raised to an unacceptably high value. Generally, this occur‐ rence dictates the time the solution should discharged. The frequency of discharging will regulated by the rate of water removal by the plants of course, but also and particularly by the

The general advice, found to have great practical utility, is to allow the rise in EC to continue until it passes a value 50 % greater than the original EC. When it reaches this value you have

Some mono crop growers a dot the procedure of discharging the solution when the target EC

The principal problems with very hard water supplies, base EC 0. 9 m.mhos or above, are these: First, because of the very high level of natural salts present, there is a large oversupply of those which are also nutrient salts, so that a smaller proportion are removed from the system due to

Second, large amounts of acid are required to neutralize the salts. The result is that' start - up solution EC, already high due to high base EC, is quickly increased by make - up water and acid additions, and there is reduced scope to assign these EC increases to useful nutrients. The practical significance is that the full base EC must be allowed at system start - up when

**10. The special program for using very hard water (0.9 or above)**

achieved check solution pH and adjust if necessary. The following examples illustrate this procedure :

**•** Solution volume in the nutrient solution tank 210 liters

94 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

tionally to the solution EC i.e., 6 divided by]/3 = 2.

hardness, manifested as base EC of the make - up water.

**•** Target EC = Desired EC + Base EC = 1.3 + '/2 (2) = 1.3 + 0.1= 1.4 m.mhos

**•** Base EC of make - up water 6

**•** Make – used water up 70 liters

**9.2. Discharging the solution**

to discharge the nutrient solution.

reaches twice the desired EC.

take up by the plants.

**•** Original target EC 1.3

target EC.

Then it follow the same procedure as described in the hard water (EC 0.4 – 0.8 m.mhos) First, because of the very high level of natural salts present, there is a large oversupply of those which are also nutrient salts, so that a smaller proportion are removed from the system due to take up by the plants.

> Second, large amounts of acid are required to neutralize the salts. The result is that' start - up solution EC, already high due to high base EC, is quickly increased by make - up water and acid additions, and there is reduced scope to assign these EC increases to useful nutrients. The practical significance is that the full base EC must be allowed at system start - up when calculating a target EC and when maintaining nutrient levels in

#### **11. Nutrient solution composition** the solution by setting a new target EC. Accordingly, when using very hard water supplies, calculation of target EC uses the following equation: Target EC = Desired EC + Base EC

 **9.2 Discharging the solution:**

Plants require 16 essential elements for their growth and development. Without these nu‐ trients, plants cannot complete their life cycles and their roles in plant growth cannot replaced by any other elements. These 16 elements divided into micro and macro element categories as sketched bellow. Then it follow the same procedure as described in the hard water (EC 0.4 – 0.8 m.mhos) **11. Nutrient solution composition** Plants require 16 essential elements for their growth and development. Without these nutrients, plants cannot complete their life cycles and their roles in plant growth cannot replaced by any other elements. These 16 elements divided into micro and macro element categories as sketched bellow.

systems. Some of the elements may be present in adequate quantities as in the water supply. Other elements will have to be added to the water. These usually are: N – P – K – Ca – Mg - Fe- Mn – B – Cu – Zn - Mo. **\*\*Ideal Concentrations (ppm) of Elements in Nutrient Solution for tomato is given below as an example** All the nutrient elements required for plant growth have to be present in the nutrient solution for soilless culture systems. Some of the elements may be present in adequate quantities as in the water supply. Other elements will have to be added to the water. These usually are:

All the nutrient elements required for plant growth have to be present in the nutrient solution for soilless culture

**Elements Symbol Concentrations N Nitrogen** N – P – K – Ca – Mg - Fe- Mn – B – Cu – Zn - Mo.

> **Iron Manganese**

**60 300-350 170 50 P K Ca Mg Fe Phosphorus Potassium Calcium Magnesium \*\*Ideal Concentrations (ppm) of Elements in Nutrient Solution for tomato is given below as an example**

**Mn**

**200**

**3-6 0.5-1.0**


#### **12. Conclusion**

It is clear to solve the problems in the arid lands as shortage of water and lack of technology and the limited income of the grower that using simple but the high technology substrate culture can be a substitute of the soil cultivation. This is because that most of the equipment produced locally, the prices of this equipment's is reasonable and can afforded by the medium class grower special the grower is producing for export. This technique is saving water, there is no need of soil sterilization, there is no for land reclamation.

The most system of the simple substrate system is the column polystyrene pot system for the small plants and the single polystyrene system for the big plants, which can isolate the plants from the high temperature.

#### **Author details**

Usama Ahmed Aly El-Behairy

Address all correspondence to: el\_behairy2003@hotmail.com

Arid Land Graduate Agricultural Research Institute (ALARI)- Ain Shams University, Cairo, Egypt

#### **References**


[7] Johnson, H. (1979). Hydroponics, "A Guide to soilless culture system". Cooperative. Extemion, California Univ.

**12. Conclusion**

from the high temperature.

Usama Ahmed Aly El-Behairy

**Author details**

Egypt

**References**


tics Conf., Chicago. P. 144 - 149.

Grower, Nov. (33 - 73).

It is clear to solve the problems in the arid lands as shortage of water and lack of technology and the limited income of the grower that using simple but the high technology substrate culture can be a substitute of the soil cultivation. This is because that most of the equipment produced locally, the prices of this equipment's is reasonable and can afforded by the medium class grower special the grower is producing for export. This technique is saving water, there

The most system of the simple substrate system is the column polystyrene pot system for the small plants and the single polystyrene system for the big plants, which can isolate the plants

Arid Land Graduate Agricultural Research Institute (ALARI)- Ain Shams University, Cairo,

[1] Abou-Hadid, A. F.; . El-Behairy, U. A; Metwally, Neveen E. and Aly, M. S. 2004. Cur‐ rent situation of soilless culture in Egypt. Regional Training workshop on soilless

[4] Ibrahim, A., El-Gindy, A., Abou-Hadid, A. and Abdel Ghafar, A. (1989). Recirculated sand culture for tomato under protected cultivation. Egypt. J. Hort. 16, No. 2 pp. 181

[5] Jensen. M. H. (1971). The use of polyethylene barriers between soil and growing me‐ dium in greenhouse vegetable production. P. 144 - 149. In. Proc. 10 th Natl. Agr. Plas‐

[6] Jensen, M.H. and Hicks, N. (1973). Exciting future for sand culture. Amm. Veg.

is no need of soil sterilization, there is no for land reclamation.

96 Soilless Culture - Use of Substrates for the Production of Quality Horticultural Crops

Address all correspondence to: el\_behairy2003@hotmail.com

culture technologies. Izmir, Turkey. March 3-5, 2004.

[2] Cooper, A.J. (1979). "The ABC of NFT", Growers Books, London, 181cp

[3] Cooper, A. (1982). "Nutrient Film Technique", Grower Books, London.


**Chapter 5**
