**Investigating Importance and Effects of Climate Changes in Agriculture in South Khorasan Province and Recognizing Appropriate Extension Education Activities in Confronting Them**

Farhood Golmohammadi<sup>1</sup> , Mohsen Arazmjoo2 , Seyed Hamid Razavi<sup>3</sup>

1 Islamic Azad University, Birjand Branch – Birjand, Iran

2 Agricultural Research- Education and Extension Organization\_ Birjand Branch – Birjand, Iran

3 Oloome Entezami University- Birjand, Iran

#### **Abstract**

In this article, author state a brief to drought management as an essential approach for regional development and maintaining employment in South Khorasan province in Iran. Rainfall is the ultimate source of water, affecting production of crops and other biomass by direct falling on the fields as well as supporting surface and ground water irrigation. However, possibilities of drought occurrence in Iran vary from once in 20 years. The frequency and intensity of extreme weather events like droughts, floods, heat/cold waves, cyclones, delayed or early onset, long dry spells, early withdrawal, and floods in drought frequented areas and droughts in flood afflicted areas have increased during the last two decades due to global warming. Since drought is defined by deviation from the normal rainfall, it can happen in all regions. Assessment and management of drought is complex due to its gradual appearance and long lasting impact or recoveries. Characteristics and impact of drought vary from region to region and year to year. Drought affects human, livestock, wildlife, bio-diversity and degrades the quality of natural resource base. This article is part of a research project titled: (( Investigating importance and effects of climate changes in agriculture in south khorasan province and recognizing appropriate extension education activities in confronting them)) that by author has been done in the Agricultural Research, Education and Extension Organization\_ Birjand Branch – Birjand, South khorasan province of Iran.

**Keywords**: Drought, Impact, desert, south Khorasan province, Iran.

## **1. Introduction**

Drought is universal phenomenon that can occur everywhere and can cause harmful impacts on human beings and natural ecosystems. Growing public awareness of the issue of global climate change has raised enormous concerns regarding its potential impacts and consequences. Although there are inconclusive findings on the specific impacts of climate

© 2012 Golmohammadi et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/ licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

change on regional water resources, many scientists have suggested that climate change is likely to increase the frequency and intensity of extreme climate events such as drought. Drought based on frequency of occurrence, severity, affected area, economic damages, environmental and social affects and severe long term impacts is very important and dangerous phenomenon compared to other disasters. Drought is one of the most important natural disasters which could be defined as: less than average annual rainfall and discordant distribution of rainfall in the region. With lack of rainfall for a long period of time; farms, gardens, pastures, and forests which their required water resources are provided from the atmosphere rainfall are damaged directly. Particularly, agriculture which has an important role in national economy and is a set of activities that its aim is supplying food needs of community and produce raw materials for other sectors including industry. Iran, with a rainfall average about 252 mm in year is among the dry regions in the world. Low rainfall, irregular distribution of rainfalls and climate warming, causes economic, environmental, political and social crisis in different areas. In recent years, impacts of drought were high on water sources, agriculture, livestock production, pastures, migration, rebellion of pests and disease. Drought can also reduce water quality, because lower water flows reduce dilution of pollutants and increase contamination of remaining water sources. Studies indicate that drought has priority to other natural disasters in the frequency of occurrence, duration, extent, loss of life, economic and social impacts and severe effects in the long run. Damages of drought will affect economic, environmental and social status of communities. Drought includes a set of negative effects which not only affect economic and social activities of farmers and related industries, but also affect those who are not actually employed in agriculture but are living in agricultural regions. Despite the relatively small share of agriculture in Australian GDP, the drought has reduced GDP by 1.6%, and has contributed to a decline in unemployment and to a worsening of the balance of trade. In a surveyed environmental, economic and social effects of drought and effect of solutions applied in order to reducing its effects in Sistan Province (Iran) and concluded that between the effects of drought (environmental, economic and socio- psychology) the economic effects are more than others, then environmental impacts and at last the least impacts were socio-psychology effects (Golmohammadi, 2006,2007,2011). Rezavi et al. (2011) surveyed economic, social, environmental, and ecological impacts of drought in Zanjan province and concluded that these impacts were economic, environmental, social and ecological respectively. Nuri and Bazrafshan (1996-2004) investigated direct and indirect effects of drought on rural economy of Sistan, and stated that direct effects include damage to crops, horticulture and animal husbandry and indirect effects include an increase in the population covered by the support relief organizations, an increase in migration from rural regions, reducing price of agricultural lands and orchards and also change rural economic structuring. South Khorasan Province in -East of Iran is one of the Provinces that in recent years have caught with very strong drought and water shortage. This problem has created many limitations and negative impacts for farmers. drought and water shortage has more effect on this region. Reliable statistics indicate that South Khorasan Province in -East of Iran will face with severe International Conference on Applied Life Sciences (ICALS2012)

water shortage and drought in the future and these problems, more than anything, would

**Figs 1., 2.** Barberry as one of main agricultural product that are resistant to drought conditions in South

**Figs 3., 4.** Saffron as one of main agricultural product that are resistant to drought conditions in South Kho-

**Figs 5., 6.** seasonal floods that not properly storing as a main source of water for resistant and living people

in drought conditions in South Khorasan Province in -East of Iran (and author Jun 2012).

affect Barberry and Saffron production.

Khorasan Province in -East of Iran (by author, 2010).

rasan Province in -East of Iran (by author, 2010).

Turkey, September 10-12, 2012

<sup>383</sup> ISALS

water shortage and drought in the future and these problems, more than anything, would affect Barberry and Saffron production.

**Figs 1., 2.** Barberry as one of main agricultural product that are resistant to drought conditions in South Khorasan Province in -East of Iran (by author, 2010).

**Figs 3., 4.** Saffron as one of main agricultural product that are resistant to drought conditions in South Khorasan Province in -East of Iran (by author, 2010).

**Figs 5., 6.** seasonal floods that not properly storing as a main source of water for resistant and living people in drought conditions in South Khorasan Province in -East of Iran (and author Jun 2012).

International Conference on Applied Life Sciences (ICALS2012)

Increase in plant diseases, Increase in soil erosion, Increase in amount and intensity of fires, De-

 In social part, it resulted in increase in frustration, anxiety and emotional problems, feeling of poverty and decrease in life level, decrease in recreational activities , increase in local divisions to supply water, weakened position of institutions and cooperative unions, weakened traditions of cooperation, increase in tend to migrate, decrease in social ceremonies, decrease in the level of education in children and juveniles, disintegrate of consistency and continuity in family system

> •To accept the risk of assigning the responsibilities to people for management drought conditions in South Khorasan Province in order to

> •Constructive interaction with the offices, plays the most critical role to achieve for objectives of management drought conditions in South

> •Formation of management drought conditions is the most important factor for participation of local communities towards sustainable ru-

> •Multidisciplinary and integrated planning in addition to bottom-up approach decision making are the most important factor in the success of management drought conditions and realization of sustain-

[1] F. Golmohammadi, M.K. Motamed, A viewpoint toward farm management and importance of barberry in sustainable rural livelihood in desert regions in east of Iran. African Journal of Plant Science Vol. 6(7), pp. 213-221, 6 April, 2012 . Available online at http://www.academicjournals.

[2] F. Golmohammadi, Study of Education and Extension Methods of Indigenous Knowledge of Rural Architecture (Case Study: Systan and Balouchestan Province). In: JOURNAL OF Housing And Rural Environment. Journal of Housing Foundation of Islamic Revolution. TEHRAN. IRAN. ISSN: 2008-4994. No. 136, Winter, 2012. 2, 2012; 30 (136) :79-94.URL http://www.jhre.ir/

[3] F. Golmohammadi, Preparing Systematic Functional Pattern of Extension to Attaining Sustainable Development of Agriculture. Title of my Dissertation for Ph.D. IN AGRIULTURAL EXTENSION AND EDUCATION . FROM : ISLAMIC AZAD UNIVERSITY\_ SCIENCE AND

[4] F. Golmohammadi, The Role of Extension Education in Participating Rural People toward Establishing and Maintaining Rural Parks in Isfahan Province. IRAN. M.SC. Thesis IN AGRIULTURAL EXTENSION AND EDUCATION. TARBIAT MODARRES

org/AJPS DOI: 10.5897/AJPS11.073 ISSN 1996-0824 ©2012 Academic Journals

Khorasan Province in order to empower them;

crease in diversity of plant species respectively.

respectively. We also recommend following solutions:

empower them;

ral development;

**4. References**

able rural development;

browse.php?a\_code=A-10-177-3&slc\_lang=fa&sid=1

RESEARCH BRANCH –TEHRAN. IRAN.2002-2007.

UNIVERSITY(T.M.U.). IRAN.1995-1998.

Turkey, September 10-12, 2012

<sup>385</sup> ISALS

**Figs 7., 8.** Some locally and medium dam projects that recently building for gathering and storing seasonal floods as a main source of water for resistant and living people in drought conditions in South Khorasan Province in -East of Iran (and author Jun 2011).

## **2. Materials and Methods**

This article is part of a research project titled: (( Investigating importance and effects of climate changes in agriculture in south khorasan province and recognizing appropriate extension education activities in confronting them)) that by author has been done in the Agricultural Research, Education and Extension Organization\_ Birjand Branch – Birjand, South khorasan province of Iran.

## **3. Results**

 Drought is one of the most important natural disasters which affect on economic, environmental and social conditions of communities. Also it might occur even in all humid and semi-humid areas, although the details and rates can be different from one region to another. south Khorasan province in -East of Iran is one of the high deserted provinces of Iran that in recent years caught with drought and water shortage. This problem, in addition reduce yield of barberry and saffron in this province, leaded to other direct and indirect environmental and socio-economical problems for barberry and saffron farmers. The results of this research indicated that between environmental, economic and social impacts of drought, the economic effects were more than others, then environmental impacts and at last were social effects. This result is consistent with the finding of shokri (2005) and Rezayi et al (2011).

In viewpoint of barberry and saffron farmers, in economic part, drought leaded to; increase in costs labor and eradicating weeds, increase in costs for water supply, decrease in purchasing power, decrease in savings, non-payment of bank loans and obligations, increase in the false financial relationship, decrease in price of crops due to reduction of quality, decrease in income due to reduction of cultivation, decrease in land price, decrease in income from side jobs, respectively.

 In environmental part, drought resulted in; Decrease in rivers flow, groundwater levels, Decrease in surface water reservoirs and ponds, Increase in weeds growing in fields, Increase in mortality of fish and other aquatic in ponds, Decrease in water quality, Increase in pest attack, Increase in plant diseases, Increase in soil erosion, Increase in amount and intensity of fires, Decrease in diversity of plant species respectively.

 In social part, it resulted in increase in frustration, anxiety and emotional problems, feeling of poverty and decrease in life level, decrease in recreational activities , increase in local divisions to supply water, weakened position of institutions and cooperative unions, weakened traditions of cooperation, increase in tend to migrate, decrease in social ceremonies, decrease in the level of education in children and juveniles, disintegrate of consistency and continuity in family system respectively. We also recommend following solutions:


#### **4. References**


[5] F. Golmohammadi, Role of farmers' education and Extension Endeavours in Productivity and water consumption management ). Poster presentation. Published in the Proceedings of the Regional Congress of Sustainable Management Science – based in Agriculture and Natural Resources. Gorgan Univ. of Agric. Sci. & Natur. Resour. Page:31. In the:(( Regional Congress of Sustainable Management Science – based in Agriculture and Natural Resources )). Gorgan Univ. of Agric. Sci. & Natur. Resour. Gorgan. Iran. 21-22 May 2011.

International Conference on Applied Life Sciences (ICALS2012)

**Allelopathy an Environmentally Friendly** 

, Zahra Hosseini<sup>2</sup>

Biological weed management is a system that incorporates the use of diverse biological organisms and biologically-based approaches including allelopathy, crop competition, and other cultural practices to significantly reduce weed densities in a manner that is similar to use of chemical herbicides alone. Interest in developing effective biological weed management systems continues to increase because of a growing awareness of problems associated with the constant and intensive use of chemical herbicides, which include surface- and groundwater contamination, detrimental impacts on nontarget organisms, development of weeds resistant to herbicides, and consumer concerns for residues on food. Among different biological methods of weed control, allelopathy could lead to reduced labour costs and increased efficiency, without any adverse effects on the environment. Many of the compounds produced by green plants that are not involved in primary plant metabolism are observed to function as chemical warfare agents against competing plants and pests. Many such natural compounds have the potential to be exploited as herbicides or as leads for discovery of new herbicides. The paper highlights the different con-

The phenomenon of allelopathy, whereby a plant species chemically interferes with the germination, growth or development of other plant species has been known and documented for over

The term allelopathy, however, was first coined in 1937 by the Austrian Professor Hans Molisch from two Greek words: allelon 'of each other 'and pathos 'to suffer'and means the "injurious effect of one organism upon the other" [16]. Today, the term is generally accepted to cover both inhibitory and stimulatory effects of one plant on another plant [16]. In 1996, the International Allelopathy Society defined allelopathy as follows: "The science that studies any process involving secondary metabolites produced by plants, micro-organisms, viruses, and fungi that influence growth and development of agricultural and biological systems (excluding animals) "[24]. Nowadays, allelopathy has a significant role in research involving sustainable agriculture, like biological weed and pest control [3]. The current trend is to find a biological solution to minimize the perceived hazardous impacts from herbicides and insecticides in agriculture production. In this regards, the harmful impact of allelopathy can be exploited for pest and weed control [7, 20].

1 Faculty of Natural Resources and Desert Study, Yazd University, Iran

2 Management and Planning Organization, Yazd County, Iran

cepts of using allelopathy for eco-friendly control of weeds.

**Keywords**: allelopathy, allelochemicals, natural compounds, weeds control

**Method for Weed Control**

Hamid Sodaeizadeh<sup>1</sup>

**Abstract**

**1. Introduction**

2000 years.

© 2012 Sodaeizadeh et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

provided the original work is properly cited.

Turkey, September 10-12, 2012

<sup>387</sup> ISALS


## **Allelopathy an Environmentally Friendly Method for Weed Control**

Hamid Sodaeizadeh<sup>1</sup> , Zahra Hosseini<sup>2</sup>

1 Faculty of Natural Resources and Desert Study, Yazd University, Iran

2 Management and Planning Organization, Yazd County, Iran

#### **Abstract**

Biological weed management is a system that incorporates the use of diverse biological organisms and biologically-based approaches including allelopathy, crop competition, and other cultural practices to significantly reduce weed densities in a manner that is similar to use of chemical herbicides alone. Interest in developing effective biological weed management systems continues to increase because of a growing awareness of problems associated with the constant and intensive use of chemical herbicides, which include surface- and groundwater contamination, detrimental impacts on nontarget organisms, development of weeds resistant to herbicides, and consumer concerns for residues on food. Among different biological methods of weed control, allelopathy could lead to reduced labour costs and increased efficiency, without any adverse effects on the environment. Many of the compounds produced by green plants that are not involved in primary plant metabolism are observed to function as chemical warfare agents against competing plants and pests. Many such natural compounds have the potential to be exploited as herbicides or as leads for discovery of new herbicides. The paper highlights the different concepts of using allelopathy for eco-friendly control of weeds.

**Keywords**: allelopathy, allelochemicals, natural compounds, weeds control

## **1. Introduction**

The phenomenon of allelopathy, whereby a plant species chemically interferes with the germination, growth or development of other plant species has been known and documented for over 2000 years.

The term allelopathy, however, was first coined in 1937 by the Austrian Professor Hans Molisch from two Greek words: allelon 'of each other 'and pathos 'to suffer'and means the "injurious effect of one organism upon the other" [16]. Today, the term is generally accepted to cover both inhibitory and stimulatory effects of one plant on another plant [16]. In 1996, the International Allelopathy Society defined allelopathy as follows: "The science that studies any process involving secondary metabolites produced by plants, micro-organisms, viruses, and fungi that influence growth and development of agricultural and biological systems (excluding animals) "[24]. Nowadays, allelopathy has a significant role in research involving sustainable agriculture, like biological weed and pest control [3]. The current trend is to find a biological solution to minimize the perceived hazardous impacts from herbicides and insecticides in agriculture production. In this regards, the harmful impact of allelopathy can be exploited for pest and weed control [7, 20].

© 2012 Sodaeizadeh et al.; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

The chemicals responsible for the phenomenon of allelopathy are generally referred to as allelochemicals or phytotoxins [8]. Allelochemicals are usually classified as secondary metabolites and are produced as offshoots in the primary metabolic pathways of plants [9]. Many such natural compounds have the potential to induce a wide array of biological effects and can provide great benefits to agriculture and weed management [3, 10].

International Conference on Applied Life Sciences (ICALS2012)

toward herbicides have been identified (www. weedscience.com). Because of all these problems, efforts are being made to find out alternative low-input strategies for weed management. In this regard, much attention has been focused on the use of allelopathic plants and their products for managing weeds in a sustainable manner [21]. Natural products release from allelopathic plants may help to reduce the use of synthetic herbicides for weed management and therefore, cause less pollution, safer agricultural products as well as alleviate human health concerns [6]. So, it is worthwhile to explore the potential of plants with strong allelopathic activity for the manage-

The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop

There is increasing evidence that allelochemicals or natural plant products derived from higher plants/microbes can be ideal agrochemicals. Initially, the reason why plants devote resources to the production of these compounds was not understood as they were regarded as functionless waste products. It is now increasingly accepted, however, that these compounds function as defensive agents against pathogens, insects and neighbouring plants [11]. Many such natural compounds have the potential to induce a wide array of biological effects and can provide great benefits to agriculture and weed management [3, 10]. Evidence showed that higher plants release a diversity of allelochemicals into the environment. Despite so much chemical diversity, allelochemicals can be broadly characterized into phenolics and terpenoids. They are released by volatilization, root exudation, death and decay of plants, and leachation from living or decaying residues [1, 18]. After release, allelochemicals are involved in a variety of metabolic processes [18]. Several factors determine their toxicity such as concentration, flux rate, age and metabolic state of plant, and prevailing climatic and environmental conditions [18]. Their amount and production varies in quality and quantity with age, cultivar, plant organ, and time of the year. Einhellig [5] mentioned that both abiotic (temperature, nutrient amount, and moisture deficit) and biotic (disease and insect damage and interaction of plans with herbivory) factors enhance the

These allelopathic chemicals are produced by a 'donor' and transmitted to a 'receiver' that can

Allelochemicals act through direct interference with physiological functions of 'receiver' such as seed germination, root growth, shoot growth, stem growth, symbiotic effectiveness or act indirectly through additive or synergistic impact along with pathological infections, insect injury and/or environmental stress. Though many of these allelochemicals exhibit inhibitory response on various morpho-physiological functions of receiver plants and such responses being observed

ment of agricultural weeds.

mulch/ residues can also give desirable benefits.

**3. Allelochemicals as natural herbicides**

amount and biosynthesis of allelochemicals in plants.

either be 'injured' or 'stimulated'.

Turkey, September 10-12, 2012

<sup>389</sup> ISALS

## **2. Allelopathy for Weed Management**

The word weed means any wild plant that grows at an unwanted place for example in fields and interferes with the growth of cultivated plants [17]. Farmers must contend with approximately 30,000 plant species identified as weeds. Among them, 250 are really important and about 80 are known to reduce crop yield [8].

Weeds have substantially adapted characteristics (e.g. produce an abundance of seed, rapid seedling growth, quick maturation, dual modes of reproduction, environmental plasticity) that enable them to grow, flourish, invade and dominate an important part of natural and agricultural ecosystems [8, 25]. In agro-ecosystems, weeds compete with crop plants for resources, interfere in crop handling, reduce crop yield and deteriorate their quality, and thus result in huge financial losses [8] . Degree of loss depends on crop species present, timing and duration of competitive interactions, and resource availability [1]. Oerke et al. [12] reported that weeds, pathogens and animal pests cause a loss of around 13.2, 13.3 and 15.6% (totally 42.1%), respectively, in the eight most important food and cash crops, even when they are intensively controlled. However, if no physical, biological or chemical measures were used to protect crops, yield losses would be around 69.8%. So, losses prevented by crop protection measures are about 27.6% of attainable production. The only basis on which it is possible to calculate an overall figure for crop losses in all crops is financial one. In US agriculture, weeds cause an overall reduction of 12% in crop yields, and this represents approximately \$32 billion in lost crop production each year (USCB 2007). In addition to the direct losses, approximately \$4 billion is spent each year on herbicides used to control pest weeds. Thus, the total annual cost of introduced weeds to US agricultural economy is about \$36 billion [13].

In light of these characteristics of weeds and their hazards, it becomes imperative to control them. Several techniques (e.g. mechanical and chemicals) are used for weed control. These techniques attempt to achieve a balance between cost of control and crop yield loss [8, 20]. Mechanical methods, such as hand weeding require enormous labour and time input. Nowadays, chemical method provides an effective strategy for weed control. Since their discovery in the 1950s, synthetic herbicides have developed as a major tool for weed management. Herbicides have helped farmers to increase yields while reducing labour. Indeed, without herbicides, labour would be a major cost of crop production in developed countries. Nevertheless, the indiscriminate use of herbicides has provoked an increasing incidence of resistance in weeds to some herbicides, changes in weed population to species more related to the crop, environmental pollution, and potential health hazards [10]. Overuse of synthetic chemicals for weed control worsens the quality of soil, water, other life support systems, human health and food [21]. Fast-developing herbicide-resistant ecotypes of weeds are also posing serious threats to agricultural production. So far, at least 334 weed-resistant biotypes belonging to 190 species (113 dicots and 77 monocots) toward herbicides have been identified (www. weedscience.com). Because of all these problems, efforts are being made to find out alternative low-input strategies for weed management. In this regard, much attention has been focused on the use of allelopathic plants and their products for managing weeds in a sustainable manner [21]. Natural products release from allelopathic plants may help to reduce the use of synthetic herbicides for weed management and therefore, cause less pollution, safer agricultural products as well as alleviate human health concerns [6]. So, it is worthwhile to explore the potential of plants with strong allelopathic activity for the management of agricultural weeds.

The use of allelopathy for controlling weeds could be either through directly utilizing natural allelopathic interactions, particularly of crop plants, or by using allelochemicals as natural herbicides. In the former case, a number of crop plants with allelopathic potential can be used as cover, smother, and green manure crops for managing weeds by making desired manipulations in the cultural practices and cropping patterns. These can be suitably rotated or intercropped with main crops to manage the target weeds (including parasitic ones) selectively. Even the crop mulch/ residues can also give desirable benefits.

## **3. Allelochemicals as natural herbicides**

There is increasing evidence that allelochemicals or natural plant products derived from higher plants/microbes can be ideal agrochemicals. Initially, the reason why plants devote resources to the production of these compounds was not understood as they were regarded as functionless waste products. It is now increasingly accepted, however, that these compounds function as defensive agents against pathogens, insects and neighbouring plants [11]. Many such natural compounds have the potential to induce a wide array of biological effects and can provide great benefits to agriculture and weed management [3, 10]. Evidence showed that higher plants release a diversity of allelochemicals into the environment. Despite so much chemical diversity, allelochemicals can be broadly characterized into phenolics and terpenoids. They are released by volatilization, root exudation, death and decay of plants, and leachation from living or decaying residues [1, 18]. After release, allelochemicals are involved in a variety of metabolic processes [18]. Several factors determine their toxicity such as concentration, flux rate, age and metabolic state of plant, and prevailing climatic and environmental conditions [18]. Their amount and production varies in quality and quantity with age, cultivar, plant organ, and time of the year. Einhellig [5] mentioned that both abiotic (temperature, nutrient amount, and moisture deficit) and biotic (disease and insect damage and interaction of plans with herbivory) factors enhance the amount and biosynthesis of allelochemicals in plants.

These allelopathic chemicals are produced by a 'donor' and transmitted to a 'receiver' that can either be 'injured' or 'stimulated'.

Allelochemicals act through direct interference with physiological functions of 'receiver' such as seed germination, root growth, shoot growth, stem growth, symbiotic effectiveness or act indirectly through additive or synergistic impact along with pathological infections, insect injury and/or environmental stress. Though many of these allelochemicals exhibit inhibitory response on various morpho-physiological functions of receiver plants and such responses being observed to be dose dependant in a linear fashion, their concentrations required for control of weeds on a field scale are impracticably higher.

International Conference on Applied Life Sciences (ICALS2012)

[2] Cock, C.E., Whichard, L.P., Turner, B., Well, M.E. and Egley, G.H. 1966. Germination of witchweed (*Striga lutea* Lour) : Isolation and properties of potent stimulant. *Science,* 154: p. 1189-1190. [3] Duke, S.O., and J. Lydon, 1987. Herbicides from natural compounds. *Weed Technology*, 1**:** p**.** 122-

[4] Economou, G., O. Tzakou, A. Gani, A. Yannitsaros, and D. Bilalis, 2002. Allelopathic effect of *Conyza albida* on *Avena sativa* and *Spirodela polyrhiza*. *Journal of Agronomy and Crop Science*, 188**,** 248.

[5] Einhellig, F. A, 1996. Interactions involving allelopathy in cropping systems. *Agron. J,* 88: p. 886–

[6] Khanh, T.D., A.A. Elzaawely,. I.M. Chung, J.K. Ahn, S.Tawata, and T.D. Xuan, 2007. Role of

[7] Kohli, R. K., D. Batish, and H. P. Singh, 1998. Allelopathy and its implications in agroecosystems.

[8] Kholi, R.K., H.P. Singh, and D.R. Batish, 2004. Allelopathy in agroecosystems. Food Products

[9] Kruse, M., M. Strandberg, and B.Strandberg, 2000. Ecological effects of allelopathic plants: a

[10] Macías, F.A., N. Chinchilla, R.M. Varela, and J.M.G. Molinillo, 2006. Bioactive steroids from *Oryza* 

[11] Mattner, S.W. 2006. The impact of pathogens on plant interference and allelopathy In: Inderjit, & Mukerji, K. G., (Eds.). *Allelochemicals: Biological control of plant pathogens and diseases.* Springer.

[12] Oerke, E.-C., H.-w. Dehne, F. Schonbeck, and A. Weber, 1995. Crop production and crop protection: estimated losses in major food and cash crops. Elsevier Science B.V. Amesterdam. [13] Pimentel, D. 2009. Invasive plants: their role in species extinctions and economic losses to agriculture in the USA. In: Inderjit, (Ed.). *Management of invasive weeds.* Springer Verlag, New

[15] Rice, E.L. 1995. Biological Control of Weeds and Plant Diseases : Advances in Applied Allelopathy.

[16] Rizvi, S.J.H., and V. Rizvi, 1992. Allelopathy: basic and applied aspects. Champan & Hall. London

[17] Rizvi, S.H.J., Mukerjee, D. and Mathur, S.N. 1981. Selective phytotoxicity of 1, 3, 7-trimethylaxanthine between *Phaseolus mungo* and some weeds. *Agricultural Biological Chemistry,*

[18] Singh, H.P., D.R. Batish, and R.K. Kohli, 1999. Autotoxicity: Concept, Organisms, and Ecological

[19] Singh, H.P., D.R. Batish, and R.K. Kohli, 2003. Allelopathic interactions and allelochemicals: new possibilities for sustainable weed management. *Critical Reviews in Plant Sciences*, 22**,** 239.

allelochemical for weed management in rice. *Allelopathy Journal*, 19**:** p. 85-96.

review. Silkeborg, Denmark, National Environmental Research Institute.

128.

893.

York.

SE1 8HN.

45 : p. 1255-1256

*J. Crop Prod*, 1: p. 169–202.

Press. New York, USA.

*sativa* L. *Steroids*, 71**:** p. 603-608.

Dordrecht, The Netherlands.

University of Oklahoma Press

[14] Rice, E.L. 1984. Allelopathy. Academic Press,Orlando.

Significance. *Critical Reviews in Plant Sciences*, 18**:** p**.** 257-272.

Turkey, September 10-12, 2012

<sup>391</sup> ISALS

## **4. Discussion**

Despite herbicidal activity of allelopathic plants, to attain significant weed reduction under field conditions a large quantity of plant materials or pellets is required. This needs heavy field work. Therefore, the possibility of its periodical application for greater weed control should be further examined [14]. The various combinations of allelopathic plants and herbicides to reduce dependence on synthetic herbicides should be tested [15]. In addition, a combination of different allelopathic plant species with strong weed-suppressing ability, may be capable of controlling more weed species than a single allelopathic plant species. Another alternative to reduce field work is to select allelochemicals from various sources, such as plants or microorganisms, and use them as herbicides in place of synthetic chemicals [15] . This procedure can have desirable results, because most natural products are broken down rather rapidly by common microorganisms and thus are not persistent pollutants in the environment, as are many of the synthetic herbicides. Among the plant products as herbicides, juglone, isolated from walnut tree has been found effective against redroot pigweed, velvetleaf and barnyard grass [22, 23]. Caffeine derived from coffee showed considerable selectivity in inhibiting germination of *Amaranthus spinosus* L. at a concentration that has no effect on blackgram [17]. Strigol, a sesquiterpenoid derivative from cotton roots is a potent germination stimulant of witchweed (Striga asiatica L. Kuntz), an obligate parasite of maize, sorghum [2] and Orobanche minor [22]. Dhurrin (sorghum); gallic acid (spurge); Phlorizin (apple root); trimethylxanthene (coffee) and cinch (eucalyptus) are some other important plant products having promising herbicidal activity. I this regard continuous study on isolation and identification of allelopathic compounds in plants and rhizosphere should be conducted. Although many biologically active compounds have been found, we still need to explore new compounds from plants and microorganisms.

## **5. Conclusions**

Increasing attention has been given to the role and potential of allelopathy as a management strategy for crop protection against weeds and other pests. Incorporating allelopathy into natural and agricultural management systems may reduce the use of herbicides, insecticides, and other pesticides, reducing environment/soil pollution and diminish autotoxicity hazards. There is a great demand for compounds with selective toxicity that can be readily degraded by either the plant or by the soil microorganisms. In addition, plant, microorganisms, other soil organisms and insects can produce allelochemicals which provide new strategies for maintaining and increasing agricultural production in the future.

## **6. References**

[1] Anaya, A.L., 2006. Allelopathic organisms and molecouls : Promising bioregulators for the control of plant diseases, weeds and other pests. In: Inderjit, & Mukerji, K. G., (Eds.). *Allelochemicals: biological control of plant pathogens and diseases.* Springer. Dordrecht, The Netherlands.


[20] Sodaeizadeh, H., M. Rafieiolhossaini, J. Havlík, and P. Van Damme, 2009. Allelopathic activity of different plant parts of *Peganum harmala* L. and identification of their growth inhibitors substances*. Plant Growth Regulation*, 59: p. 227–236

International Conference on Applied Life Sciences (ICALS2012)

**Improving Bread Wheat Productivity and** 

Agronomy Department, Faculty of Agriculture, South Valley University, Qena, Egypt

**Environment in Upper Egypt**

Abd El-Lattief, E.A.

**Abstract**

this study.

differences.

**1. Introduction**

**Reduce Use of Mineral Nitrogen by Inoculation** 

**with** *Azotobacter* **and** *Azospirillum* **Under Arid** 

The effect of integrated use of mineral N fertilizer (Urea) and biofertilizer (*Azotobacter* and *Azospirillum*) on grain yield, grain yield attributes and harvest index of wheat was assessed. Two field experiments were carried out on a sandy soil in the Experimental Farm of the Faculty of Agriculture, South Valley University at Qena Governorate, Egypt. The recommended N (230 kg N ha-1) and biofertilizer (*Azotobacter* and *Azospirillum*) were applied alone and in various combinations among them. A randomized complete block design, with three replications, was used in

Treatments significantly affected plant height, spike length, number of spikelets/spike, kernel weight /spike, 1000-kernel weight, grain and straw yields and harvest index. The highest values of such traits were obtained in treatment T11 (75% mineral N + biofertilizer with *Azotobacter* and *Azospirillum*). However, T12 (50% mineral N + biofertilizer with *Azotobacter* and *Azospirillum*) re-

uninoculated) but the differences among the two treatments almost did not attain the statistical

From this study, it can be concluded that the biofertilizers (double-inoculation of *Azotobacter* and *Azospirillum*) of efficient strains could save 25 or 50 % of the recommended dose of mineral N.

The high cost of chemical nitrogenous fertilizers and the low purchasing power of most of the farmers restrict its use in proper amounts, hampering crop production. Besides, a substantial amount of the urea-N is lost through different mechanisms including ammonia volatilisation,

The utilization of biological nitrogen fixation technology can decrease the use of urea-N, prevent the depletion of soil organic matter and reduce environmental pollution to a considerable extent [3, 4]. Also, Use of biofertilizers on Egyptian soils has decreased the pH, which had led to increased availability of trace elements that enhance plant growth. Bio-fertilizers are eco-friendly

denitrification and leaching losses, causing environmental pollution problems [1, 2].

sulted also higher values for the above mentioned traits comparing with T1

**Keywords**: Wheat, Biofertilizers, Azotobacter, Azospirillum, Grain yield.

© 2012 El-Lattief; licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the

original work is properly cited.

Turkey, September 10-12, 2012

<sup>393</sup> ISALS

(100% nitrogen and

