**4. Determination and evaluation of water productivity**

As improvement of WP and identification of its sources of inefficiencies are set as one of the top priorities in Iran, especially in KRB, some studies were conducted in the downstream areas of L-KRB located in the DA plain in the Khuzestan province (**Figure 3**).

The main objectives of these studies were to determine and evaluate WP of irrigated wheat, as a major cultivated crop in DA. Moreover some recommendations and simply applicable management approaches for the better management of irrigation practices and the amelioration of salinity-waterlogging hazards on crop yield and WP were suggested.

The researches were conducted in seven farmers' fields, typical of the farms in the region and during cropping season of 2006–2007. In **Figure 3** location of the selected fields is demonstrated.

The measured parameters were irrigation water inflows and runoffs; soil texture; soil and water salinity; soil and water pHs; soil organic matter; the P, K, Fe, Mn, Zn, and Cu elements of the soil profile; depth and quality (EC) of groundwater during growth season; and finally crop yield.

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

reasons for the farmers' higher interests on wheat cultivation.

2003), and their outlet is HAA Wetland in the border of Iran-Iraq [16].

**saline areas of lower KRB**

**3. Amelioration and management approaches for improving WP in the** 

There is no doubt that one of the most important requirements for the reclamation of lands in the L-KRB is installation of adequate drainage network for the entire irrigated area. Installation of drainage network is a fundamental solution to improve the quality of salt-affected soils in the L-KRB. Drainage system will reduce the adverse effects of shallow water table and waterlogging issues in the agricultural lands. Hence it will contribute to the improvement of crop production and crop WP. Promising efforts have been initiated by the government in this regard, but still the progress is low and very costly.

To avoid further salinization of agricultural lands and to ameliorate the current

One of the most important prerequisites to enable sustainable crop production in the area is the development of a monitoring network for observing the effect of different management practices on the salt content of groundwater as well as the salt and water balance of the crop's root zone. The regular monitoring and data acquisition will provide the database required for providing the best measures to prevent restoration of soil and water salinity and secondary salinization of the crop root zone. Moreover, water and salt balance studies at the watershed level will increase the capability to predict the role of

Salinity and depth to shallow water table in DA were monitored in observation wells during November 2003 to April 2004 [18, 19]. There was a large variation in salinity of groundwater ranging between 4 and 100 dS/m. No trend of salinity changes throughout the study area was found. However, trend of groundwater salinity changes may partly be explained in regard to the soil texture variation in a manner that was lower in light-textured soils than that of heavier textured ones.

situation, the communities and agricultural agencies are called to apply sound

management practices until adequate drainage systems are installed.

any hydrological impacts on the fate and behavior of catchments' salinity.

with rain gauges.

The total rainfall in Susangerd and Bostan towns' climatological stations are 180 and 200 millimeter, respectively. The agricultural service centers also are equipped

Current crops in Azadegan Plain in southern L-KRB include cereals (such as wheat, barely, rice), vegetables (such as melon, watermelon, tomato, cucumber, eggplant, okra, lettuce, cabbage, carrot, radish, onion, etc.), grains such as beans, and fodder crops (such as alfalfa, barely, maize, and sorghum). More than 78% of agricultural production in Azadegan Plain is dominated by grains, mainly wheat and barley [16, 21]. This is because of soil salinity and sodicity with high toxic elements which makes serious limitation for cultivation of other crops. Currently water supply limitations, agriculture economy (guaranteed purchase of with by the government), and security problems in the region (wheat need less labor, less irrigation, and in overall less need for the stay of farmer in his land) are some other

The main challenge of agriculture in this region is waterlogging and soil salinity. Waterlogging and secondary soil salinization occur in a certain period of the year. For example, early November is planting date of wheat cultivation system in DA. Late November is the first irrigation for land preparation, and the harvest time is in late May. Deep percolation losses of irrigation during this period cause rises in water table. The peak of water table rise is in February. The salinity [Electrical conductivity (EC)] of shallow groundwater and EC of irrigation water in this area are about 6–9 and 3 dS/m, respectively. The highest depth of water table depth is between 0 and 1.2 m. Operation of main drains has started in recent decade (in

**182**

#### **Figure 3.** *The study area and location of the selected fields.*

**Table 1** shows some soil and water characteristics of the studied farms measured prior to the planting stage. Crop yield and yield components were measured through 20 field samples before harvest. The amount of applied irrigation water was measured by using Washington State College flume (WSC) flumes of different types. The irrigation intervals were the same as practiced by the farmers in the selected area.

WPs of wheat crop were calculated using the measured total applied waters and measured crop yields. The results are shown in **Table 2**.

The range of WP in the country is generally wide, and for the wheat crop, it is between 0.56 and 1.46 kg/m3 [3, 4]. Analysis of measured WPs in the DA area also indicates that the range of WP values is relatively high and varies between 0.24 and 0.86 kg/m3 (**Table 2**).

Results indicated that in general by increasing the farm sizes the amount of water consumed per hectare increases. This fact indicates the higher problems associated with irrigation water management in larger field sizes. The lack of required equipment and facilities, lack of farmer's skills, and shortfalls in proper land leveling have led to higher water losses and hence higher water applications (even three times more) in the larger farm sizes.


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*Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas…*

F1 3109 517 2392 0.77 F2 3460 522 1022 0.30 F3 2062 477 1336 0.65 F4 3792 505 1453 0.38 F5 3527 553 3032 0.86 F6 2311 553 4851 2.09 F7 5933 517 1431 0.24

**/ha) ET (mm) Yield (kg/ha) WUE (kg/m3**

**)**

Evaluation of the relationships between WP and applied water, yield, initial soil salinity, initial groundwater salinity, groundwater depth, and farm sizes of the selected fields indicated that there was no clear and distinct correlation between WP and these factors in all cases. In other words, a combination of these factors is affecting WP, and meanwhile managerial factors are more prominent than the basic physical factors. Consequently, sources of inefficiencies and the limiting factors affecting WP in southern part of L-KRB are complex and can be categorized into four main factors as follows:

• Sociocultural problems governing the area and causing low motivation for investment in irrigation management and on-farm improvement activities by

• Infrastructure limitations and lack of technical supports (e.g., inadequate drainage, no reclamation activities, and incomplete irrigation and drainage networks) that need extensive planning and investments and should be sup-

• Managerial issues and limitations whose solutions are simple and do not need

The results indicated that the issues and challenges hindering improvement of WP in all the selected fields are not the same and vary depending on the farmer's characteristics, the farmer's management, and the location of the farms. Some of

Traditional common irrigation practice in the area is a combination of borderbasin irrigation methods. It consists of the long borders (till 400 m) which are divided into different basins (12–15 in wide). Every basin receives its own water from the previous basin. The applied water remains for a long time in the first basins before flowing into the next one (**Figure 4**). This causes stagnation of water in the basin for a long period and stuffiness of the cultivated seeds. As usual the inflow rates to the plots are too high, and there are soil erosions, soil movements,

As there is not enough control on irrigation cutoff time, large amounts of outflows concentrate in the lower parts of the plots and create surface

• Hindering factors that are out of the farmer's management control and authority (e.g., irrigation intervals and rationing) and shortage of agricultural inputs (e.g., fertilizers, other agrochemicals, equipment and machineries, etc.)

*DOI: http://dx.doi.org/10.5772/intechopen.86891*

*Applied waters, crop yields, and WPs of wheat in different fields.*

**Farm code Water applied (m3**

the farmers

**Table 2.**

ported more by the government

these limitations and issues are elaborated below:

and washing off of the cultivated seeds.

much investments and could be accomplished easily

#### **Table 1.** *Some soil and water characteristics of the selected fields.*

*Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas… DOI: http://dx.doi.org/10.5772/intechopen.86891*


**Table 2.**

*Multifunctionality and Impacts of Organic and Conventional Agriculture*

**184**

**Table 1.**

**Farm code**

0.86 kg/m3

**Figure 3.**

**Area (ha)**

between 0.56 and 1.46 kg/m3

(**Table 2**).

*The study area and location of the selected fields.*

times more) in the larger farm sizes.

**Soil texture**

measured crop yields. The results are shown in **Table 2**.

*Some soil and water characteristics of the selected fields.*

**EC (dS/m) (30 cm depth)**

F1 1.05 SiL 26.4 105 8.8 F2 1.47 SiCL 10 205 39 F3 4.49 CL 52.6 180 71.5 F4 3.44 C 17 195 31 F5 1.73 C 21.5 182 48 F6 0.46 SiC 21.3 173 46 F7 5.24 C 10.5 213 8.7

**Table 1** shows some soil and water characteristics of the studied farms measured prior to the planting stage. Crop yield and yield components were measured through 20 field samples before harvest. The amount of applied irrigation water was measured by using Washington State College flume (WSC) flumes of different types. The irrigation intervals were the same as practiced by the farmers in the selected area. WPs of wheat crop were calculated using the measured total applied waters and

The range of WP in the country is generally wide, and for the wheat crop, it is

indicates that the range of WP values is relatively high and varies between 0.24 and

Results indicated that in general by increasing the farm sizes the amount of water consumed per hectare increases. This fact indicates the higher problems associated with irrigation water management in larger field sizes. The lack of required equipment and facilities, lack of farmer's skills, and shortfalls in proper land leveling have led to higher water losses and hence higher water applications (even three

> **Depth of water table (cm)**

[3, 4]. Analysis of measured WPs in the DA area also

**EC of ground water (dS/m)**

*Applied waters, crop yields, and WPs of wheat in different fields.*

Evaluation of the relationships between WP and applied water, yield, initial soil salinity, initial groundwater salinity, groundwater depth, and farm sizes of the selected fields indicated that there was no clear and distinct correlation between WP and these factors in all cases. In other words, a combination of these factors is affecting WP, and meanwhile managerial factors are more prominent than the basic physical factors. Consequently, sources of inefficiencies and the limiting factors affecting WP in southern part of L-KRB are complex and can be categorized into four main factors as follows:


The results indicated that the issues and challenges hindering improvement of WP in all the selected fields are not the same and vary depending on the farmer's characteristics, the farmer's management, and the location of the farms. Some of these limitations and issues are elaborated below:

Traditional common irrigation practice in the area is a combination of borderbasin irrigation methods. It consists of the long borders (till 400 m) which are divided into different basins (12–15 in wide). Every basin receives its own water from the previous basin. The applied water remains for a long time in the first basins before flowing into the next one (**Figure 4**). This causes stagnation of water in the basin for a long period and stuffiness of the cultivated seeds. As usual the inflow rates to the plots are too high, and there are soil erosions, soil movements, and washing off of the cultivated seeds.

As there is not enough control on irrigation cutoff time, large amounts of outflows concentrate in the lower parts of the plots and create surface

#### **Figure 4.**

*The traditional (left) and recommended optimum border-basin irrigation (right) methods.*

waterlogging problems. Recommend that by using a farm ditch alongside the border and construction of proper intakes, each basin to receive its inflow water individually (**Figure 4**).

Water intake and proper conduct of water into the irrigation plots is another issue. Farmers should pay high efforts to control the inflow, and this makes waste of the irrigation time. Consequently it causes poor water management and waste of water. Recommend that by construction of temporary and low-cost intake structures (gates), water intake and hence water management to be facilitated and improved.

Improper shaping of the plots in accordance with the land slope causes uneven water distribution in the basins.

Improper land preparation and agronomic practices (weed control, planting date, etc.) are some inefficiencies and shortfalls in regard to the crop production and improvement of WP in the studied area.

Considering the above limitations and issues, the following solutions and measures are recommended for improving WP in the saline areas of L-KRB:

• Conversion of traditional common irrigation practices to proper modern basinborder irrigation methods

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*Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas…*

• Application of on-farm management improvement instructions provided by

• Conduct of training programs for the farmers and supervision of the farms by irrigation experts in order to provide required guidance for the upgrading of

• Provision of the required structures and enabling conditions for the volumetric allocation of water to the farmers and implementation of proper cropping patterns

**5. Evaluation of the best management practices for improving WP in the** 

The main objective of this section is to find out cost-effective and short-term solutions for enhancing WP under salinity conditions. According to this necessity,

• Identification of simple management practices for reducing soil salinity stress

• Recognition of the effects of different cultivation/sowing methods on wheat's

The experiments were conducted during cropping season of 2006–2007 in DA plain in L-KRB. The experimental area was located between 47° 55′ to 48° 30′ E longitude and 31° 15′ to 31° 45′ N latitude, and it is about 3–12 m above the mean sea level. Soil texture was silty clay loam (SCL) to clay loam (CL). Soil's average pH was 7.8, and average soil salinity at the depth of 0–90 cm was 10.5 dS/m. Sowing was

The source of irrigation water was Karkheh River. The EC of groundwater and

Groundwater depth at the early stages of the growth season (in winter) and before the start of rainfalls and irrigation season was at the depth of 2.4 m. It was gradually raised by the start of irrigation events and changed from 35 to 98 cm from

T1 = Border irrigation + sowing by centrifugal broadcaster + one pass disk.

T4 = Basin irrigation + sowing by centrifugal broadcaster + one pass disk.

Tc = Traditional irrigation and sowing method by farmer (as control).

T5 = Basin irrigation + sowing by seed drill machine (Taka type).

T3 = Border irrigation + sowing by three-row bed seeder (Barzegar-e Hamedani type).

T6 = Basin irrigation + sowing by three-row bed seeder (Barzegar-e Hamedani type).

Dimensions of plots for the T1, T2, treatments (border irrigation) were 160 m x 10 m, while the plot dimensions of plots for the T4, T5, treatments (basin irrigation) were 40 m x 10 m. The selected dimensions were optimal sizes and were selected

• Determination and comparison of WP values under different irrigation managements, i.e., traditional vs. improved border-basin irrigation methods

the following targets were identified for the saline areas of L-KRB:

*DOI: http://dx.doi.org/10.5772/intechopen.86891*

irrigation management and performances

the rural extension services

**salt-prone areas of lower KRB**

and improving agricultural WP

done in November and the crop was harvested in May.

irrigation waters were 11.3 and 1.4 dS/m, respectively.

The experimental treatments were as follows [19]:

based on US Soil Conservation Service (SCS) criteria.

T2 = Border irrigation + sowing by seed drill (Taka type).

soil surface during the growth season.

(**Figure 4**)

WP in the area


*Water Productivity Improvement Under Salinity Conditions: Case Study of the Saline Areas… DOI: http://dx.doi.org/10.5772/intechopen.86891*

