Effect of irrigation on water use, water-use efficiency, growth and yield of mungbean

Abstract

Mungbean ( Vigna radiata (L.) Wilczek) was grown on sandy loam soil (typic Ustochrepts) under four irrigation schedules: irrigation at cumulative evaporation from USWB Class A pan equal to 200 mm (I 200), 300 mm (I 300), 400 mm (I 400) and no post-sowing irrigation (I 0) during a summer season (April–June) in India. The experiment was planned to study changes in soil water, growth and productivity in relation to irrigation schedules for efficient utilization of limited irrigation water in mungbean. Water use increased with frequency of irrigation and comprised 61, 55, 50 and 25% of pan evaporation during the growing season in I 200, I 300, I 400 and I 0 irrigation schedules, respectively. Water extraction decreased with soil depth in all the irrigation schedules. However, the plants extracted more water from deeper soil layers in the I 300 adn I 400 than in the I 200 I 0 schedules. The highest water-use efficiency was recorded in I 0, followed by I 300, I 400 and I 200. The leaf area index, crop growth rate, biomass, seed yield and partitioning of dry matter from above-ground plant parts to grains were significantly higher in I 300 followed by I 400, I 200 and I 0. The I 400 schedule had the highest harvest index. Seed yield was controlled primarily by pod density, while variation in seed size and grain number per pod had little influence on grain yield. The study has shown that irrigation at 300 mm pan evaporation is more beneficial, in terms of water economy and productivity, than the frequent watering at 200 mm pan evaporation in mungbean.