Effects of irrigation regime and frequency on yield and water efficiency of mung bean (Vigna radiata L.) at Kobo irrigation scheme, Kobo Ethiopia

Abstract

An appropriate supply of the right amount of irrigation water at the right time of growth of early maturing cash crops is necessary to achieve sustainable utilisation of water resources. This study aimed to determine the optimal crop water requirement and irrigation scheduling on yield and water use efficiency of mung bean (Vigna radiata L.). The experiment consisted of nine treatments with a factorial combination of three crop water levels (75% ETc (30 mm), 100% ETc (40 mm), and 125% ETc (50 mm)) and three irrigation intervals (10, 14 and 18 days) laid out in a randomised block design with three replications. The analysis was carried out using R software and mean separation was performed using the LSD test at the 5% probability level. The analysis of variance showed that the grain yield and water use efficiency were significantly affected (P ≤ 0.05) by the main effects of irrigation interval and crop water levels, and their interaction. Mung bean grain yield decreased and crop water use efficiency worsened when the crop water level declined and the irrigation interval increased. The maximum mean grain yield (1722 kg/ha) was recorded from 100% ETc applied at 10 day intervals, while the minimum (753 kg/ha) was recorded from 75% ETc applied in 14 day intervals. The highest crop water use efficiency (1.20 kg/m3) was noted from 75% ETc applied at 18 day intervals; this was not significantly different from treatments 75% ETc in at 10 day intervals (0.83 kg/m3), and was also not significantly different from 100% ETc applied at 10 day intervals and at 18 day intervals (0.82 kg/m3 and 0.87 kg/m3 respectively). The lowest crop water use efficiency, (0.56 kg/m3) was obtained from 75% ETc applied at 14 day intervals. The study concluded that the optimum grain yield and crop water use efficiency were obtained by applying 100% ETc (40 mm) at 10 day intervals.