عنوان مقاله [English]
Background and objectives: Although more than 90 percent of consumed water used in agricultural sector, water is the major limiting factor for agricultural development in Iran. Over the past few years increasing agricultural crop water productivity thorough deficit irrigation methods has been studied by agricultural researchers and planners. Although Lorestan province is one of the major producers of lentil, the effects of deficit irrigation on its yield is not studied yet in this province as well as its neighborhoods. Therefore this study was carried out in order to study the effect of deficit irrigation on the yield and yield components of lentil (Gachsaran cultivar) in Khorram Abad, Lorestan province.
Materials and methods: A field experiment was conducted in the research farm of Lorestan University as randomized complete block design with four irrigation treatments (100, 75, 50 and 25 percent of actual crop evapotranspiration measured in the micro lysimeter) and four replications. Average of the measured evapotranspiration in the four micro lysimeters located at the research farm was considered as the crop water requirement of 100% treatment (Control treatment). The crop water requirement of other treatments was calculated based on corresponding level of irrigation (75, 50 and 25 percent). Volume of irrigation was calculated based on crop water requirement, area of plot and irrigation efficiency (75%). At harvest time 10 plants were taken randomly from the two middle rows of each plot and were used to measure or calculate traits such as plant height, number of main branches, the number of branches per plant, number of pods per plant, number of seeds per plant, biological yield, grain yield, water use efficiency (based on grain yield) and crop water productivity (according to the average price of lentils in Lorestan). Finally the statistical analysis included analysis of variance and mean comparison test by Duncan method at five percent level were done using MSTATC software.
Results: Results of this study showed that lowest and the highest grain yield were obtained 1022 and 1381 kg per hectare respectively in treatments of 25% and 75 % irrigation application. Water use efficiency and water productivity in the treatments of 25% and 50% irrigation application was the highest and in the treatment of 100% was the lowest. Results of statistical analysis indicated that amount of irrigation had significant impact (1%) on the characteristics of the number of pods per plant, number of seeds per plant, biological yield, grain yield, water use efficiency and crop water productivity.
Conclusion: Considering the high water use efficiency and water productivity of treatment 50% irrigation application and small differences between grain yield of the treatments 50% and 100% irrigation application it can be suggested to apply 50% irrigation requirement of lentil in case of water scarce condition.