Document Type : Research Article

Authors

1 Razi University, Kermanshah

2 Razi

Abstract

Introduction: Expansion of the area of oilseed crops such as soybean is one of the policies of Iranian agricultural policy makers as Iran is one of the major oilseed importers in the world. However, the area of this crop in Kermanshah province is negligible, but it could be cultivated in most parts of this province. The quantity and quality of the produced grain could be affected by environmental factors such as weather parameters and water availability. The aim of the current study was to investigate the effects of levels of deficit irrigation on the quantity and quality of soybean crop yield in Kermanshah, Iran.
Materials and Methods: For this purpose, a field study was conducted as randomized complete block design with four replications and four irrigation treatments at the research farm of Razi University, Kermanshah in 2012. The size of each plot was 4 * 4 m. Irrigation treatments consisted of four irrigation levels: 20% over irrigation (T4), full irrigation (T3 as control), 20% less irrigation (T2) and 40% less irrigation (T1). The reason to choose T4 treatment was the lack of confidence in estimated crop evapotranspiration as there was no local calibration of crop coefficient (Kc) for this crop. The required water for T3 treatment was calculated based on daily weather data using FAO-Penman-Montith equation. Daily weather data was recorded in a weather station which was located in the research farm and is available in the www.fieldclimate.com. As there was no rainfall during the crop season, all of the required water was supplied through irrigation. The required water for treatments of T1, T2 and T4 was considered as 60%, 80% and 120% of T3 treatment. The required water was applied using a hose connected to a volumetric flow meter with a liter precision. Total amount of applied water during the crop season was 4399, 5865, 7331 and 8797 m3.ha-1 in the treatments. Fertilizers were applied based on the recommendations of soil fertility experts. Weeds were controlled manually. Finally, the area of two square meters in the middle of each plot was harvested in order to determine crop yield in terms of grain, biomass, stem, pod, seed protein content and fat percentage and also water productivity index. Dry weights of the samples were measured after drying samples in the oven for48hours at 70° C. The percentage of fat and protein in the grains are also measured in the laboratory. Water productivity index was calculated for each treatment by dividing crop yield (in terms of grain, biomass, protein and fat) over seasonal water use. Statistical analysis of the results is also done using MSTATC software.
Results and Discussion: The highest and lowest crop yields were measured respectively in the treatments T4 and T1.The mean value of grain yield was 1084, 1367, 1716 and 1940 kg.ha-1,respectively in the treatments T1, T2, T3 and T4. These results showed a 36% decrease in the grain yield by decreasing 40% in the amount of supplied water. However, biological yield was decreasedby the level of irrigation, but the rate of reduction was lower than that of grain yield. By reducing irrigation application, thepercentage of grain protein content increased while the percentage of fat in the grain decreased. Considering simultaneous reduction in grain yield and fat content in the grain, severe reductions in fat yield (oil content) were observed under water stress conditions. Crop yield in terms of fat was reduced by 26.2 and 50.1 %, respectively in treatments T2 and T1 in comparison with T3 (control treatment). The maximum and minimum percentages of protein in the treatments were 31% and 27%, respectively in the treatments T1 and T4. Maximum water productivity in terms of grain, biomass and protein was achieved in T1 treatment respectively with the amounts of 0.24, 0.81 and 0.077 kg.m-3. Maximum and minimum fat percentage was 0.052 and 0.040 kg.m-3, respectively in the T4 and T1 treatments. In addition,the results indicated that water productivity index in terms of grain, biomass and protein increased while they decreased in terms of fat yield.The results of statistical analysis indicated that water productivity index in all terms except protein had significant differences (at 5%) with T3 treatment.
Conclusion: Crop yield and water productivity (except in terms of fat) was increased by increasing applied water. Considering all indices of treatment T2 (20% deficit irrigation), itwas suggested as the best treatment.

Keywords

1- Aminifar J., Mohsenabadi G.H., Biglouei M.H., and Samiezadeh H. 2012.Evaluation of phenological stages and yield of soybean cultivars under deficit irrigation conditions in Rasht region. Iranian Journal of Field Crops Research, 10 (2): 428-434. (in Persian with English abstract)
2- Babazade H., and Sarai Tabrizi M. 2012. Assessment of Aqua Crop model under soybean deficit irrigation management conditions. Journal of Soil and Water, 26 (2):329-339. (in Persian with English abstract)
3- Bayat E., Sepehri A., Ahmadvand G., and Dory H.R. 2010. Effect of water stress on water use efficiency and drought tolerance indices of pinto bean genotypes.11th Iranian Crop Science Congress. Environmental Sciences Research Institute, Shahid Beheshti University, Tehran. (in Persian)
4- Behtari B., Ghassemi – Golezani K., Dabbagh - Mohammadi Nasab A., Zehtab – Salmasi S., and Toorchi M. 2008. Influence of water deficit on oil and protein content of soybean (Glycine max L.) seed. Journal of Agricultural Science, 17(4): 65-73. (in Persian with English abstract)
5- Brown E.A., Caviness C.E., and Brown D.A. 1985. Response of soybean cultivars to soil moisture deficit. Agronomy journal, 77 (2): 274-278.
6- Cober, E.R and Voldeng H.D. 2000. Developing high-protecting, high-yield soybean population and lines. Crop Science, 40 (1):‌ 39-42.
7- Dehghanisanij H. 2010. Deficit irrigation and agricultural water use efficiency. First National Conference on environmental stresses in agricultural Science. Birjand University, (in Persian)
8- Ehsani M., and Khaledi H. 2004. Water productivity in agriculture. Iranian National Committee of Irrigation and Drainage. (in Persian)
9- English M.J., Musick J.T., and Mutry V.V.N. 1992. Deficit irrigation. P 361-393, In: Howell, J.G., and Solomons, K.H. (ed). Management of farm irrigation systems. ASCE publication, New York, USA.
10- Farooq M., Wahid A., Kabayashi N., Fujita D., and Basra S.M.A. 2009. Plant drought stress: effect, mechanisms and management. In: Sustainable Agriculture. E. Lichtfouse, M. Navarrete, P. Debaeke, S. Veronique and C. Alberola. Springer Netherlands, 153-188.
11- Gonzalez-Rodringuez A.M., Martin-divera A., Morales D., and Jimenez M.S. 2005. Physiological responses of taga saste to a progressive drought in its native environment on the Canary Islands. Environmental and Experimental Botany, 53 (2):195-204.
12- Haghiabi A. 2007.Effect of deficit irrigation on soybean yield in Khorramabad. Ninth National Seminar on Irrigation and Evapotranspiration. Kerman. (in Persian)
13- Hobbs E., Mundel H. 1983. Water requirements of irrigated soybean in southern Alberta. Canadian Journal of Plant Science, 63 (4): 855-860.
14- Karam F., Masaad R., Sfeir T., Monzer O. and Rouphael Y. 2005. Evapotranspiration and seed yield of field grown Soybean under deficit irrigations. Agricultural water Management, 75 (3): 226-244.
15- Karimi M., Esfahani M., Bigluei M.H., Rabiee B., and Kafi Ghasemi A. 2009. Effect of deficit irrigation treatments on morphological traits and growth indices of corn forage in the Rasht Climate. Electronic Journal of Crop Production, 6(2): 91-110. (in Persian with English abstract)
16- Khajepoor M.R. 2008. Industrial crops. Jehad daneshgahi press. Isfahan. (in Persian)
17- Khajouei Nejad G.H., Kazemi H., Alyari H., Javanshir A., and Arvin M.J. 2006.Effects of irrigation regimes and plant density on yield, water use efficiency and seed quality of three soybean cultivars Glycine max L. as summer crop in the Kerman climate. Journal of Scienceand Technology of Agriculture and Natural Resources, water and soil science, 9(4):137-151. (in Persian with English abstract)
18- Kiani A.R., and Hezarjaribi A. 2010. Assessment of deficit irrigation strategy in the improvement of water use efficiency (case study on some wheat cultivars). First National Conference on environmental stresses in agricultural Science. Birjand University. (in Persian)
19- Latifi N. 1994. Soybean agronomy (agronomy, Physiology, uses). Jehad daneshgahi press, Mashahad. (in Persian)
20- Misra R.D. 2010. Deficit irrigation for reducing agricultural water use. Pant University of agriculture and technology, India. From http://www.gbpuat.ac.in/acads/cag/caft/lect/5.pdf. Last access date: 8 August 2014.
21- Molden D. 1997. Accounting for water use and productivity. SWIM Paper 1. International irrigation management institute. Colombo, Sri Lanka, 16 pp.
22- Safari M. 2007. Effects of irrigation on yield and yield components of soybean in Kerman. Ninth National Seminar on Irrigation and Evapotranspiration. Kerman. (in Persian)
23- Sepaskhah A.R., Tavakoli A.R. and Mosavi S.F. 2007. Principles and application of deficit irrigation. Publications of the National Committee on Irrigation and Drainage.
24- Sinit N. and Kramer P. 1997. Effect of water stress during different stages on growth of soybean. Agronomy journal, 69 (2): 274-277.
25- Vieira R.D., Tekrony D.M., and Egli D.B. 1992. Effect of drought and defoliation stress in the field on soybean seed germination and vigor. Crop Science, 32 (2): 471-475.
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