Effects of regulated deficit irrigation on crop water productivity, yield components, and yield response factor of common bean (Phaseolus vulgaris L)

Abstract

Due to declining water resources allocated to agriculture and rapid population growth, it is important to use water efficiently and increase crop water productivity (CWP). Deficit irrigation is considered an important strategy to achieve this goal. For this purpose, field experiments were conducted at the research farm of the Agriculture Faculty on Kabul University campus for two continuous years (2018-2019). The experiment consisted of four treatments, including full irrigation (ET100), 80% (ET80), 60% (ET60), and 40% (ET40) arranged in a randomized complete block design with three replications. Compared to ET100 and ET80, the ET60 and ET40 treatments significantly (P<0.05) reduced the duration of flowering and pod formation. The bean crop also showed best performance in plant height, number of leaves per plant, leaf area, leaf area index, number of pods per plant, number of seeds per pod, length of pod, 100-seed weight, and total grain yield in the ET100 and ET80 treatments. Moreover, significantly greater values of crop water productivity (CWP) and lower value of Ky were observed in ET80 compared to ET100, ET60 and ET40. Overall, the experiment results showed that regulated deficit irrigation can effectively increase water productivity. Supplying only 80% instead of full water requirement can result in a higher common bean CWP. This is of particular importance in water-scarce areas, where the water saved based on this practice can be used to irrigate additional acreage.