Legume crops enhance water use efficiency under intercropping system with wheat

Abstract

A comparative analysis of three legume crops (faba bean, peas, and clover) as intercrops with wheat was conducted under three irrigation treatments (100%, 85%, and 70% ETc) to evaluate their contributions to enhancing the complementary effect that improves water usage and wheat production. The irrigation water applied to wheat intercropping systems was equivalent to that applied to sole wheat, indicating that both intercrops utilized the irrigation designated for sole wheat. The faba bean-wheat intercropping system exhibited the greatest water utilization and soil accessible nitrogen across the three irrigation regimens. The production of intercropped wheat was maximized in the peas intercropping system, in contrast to the yield of sole wheat. The intercropping system of peas achieved the highest land equivalent ratio (LER), water equivalent ratio (WER), and change in water use, indicating enhanced water use efficiency. In an irrigation scenario of 85% ETc, the LER and WER for the peas intercropping system exceeded those of the faba bean intercropping system under 100% ETc. The intercropping system with peas had the highest monetary advantage index value. This suggests that, in the context of limited water resources, intercropping peas with wheat is advisable to enhance the utilization of available water resources.

 Keywords: faba bean, peas, clover, available soil N, land and water equivalent ratios, change in water use, momentary advantage index