Improving water use efficiency under deficit irrigation in the Jordan Valley

Abstract

The Jordan Valley is the prime irrigated agricultural area in Jordan which suffers shortage of water putting severe limitation on water allocation to farmers. To alleviate the problem, deficit irrigation was proposed for some vegetables such as bell pepper. Two field experiments in two growing seasons were conducted using bell pepper (Capsicum Annuum L.) to assess the effect of deficit irrigation on yield, water use efficiency (WUE), and water productivity (WP). The treatments were three irrigation levels: 100% (T1), 80% (T2), and 60% (T3) of the calculated crop evapotranspiration (ETc) using class A pan method. A cost-benefit analysis was carried out to determine the best economically suitable season for crop growth. The yields in both seasons were higher under T1, but there was no difference in WUE and WP between T1 and T2. The yield, WUE, and WP for T3 were significantly lower than for T1 and T2. Therefore, it is recommended to irrigate at 80% of ET. The best results were obtained for the total gross margin and the net present value in the winter season. Using deficit irrigation reduces water usage without significant yield loss, meanwhile maintaining relatively high WUE and supporting the sustainability of agriculture in the Jordan Valley.