Soil water dynamics in spring and summer mungbean under rainfed and irrigation production systems – Narrabri 2016–17

Abstract

Key findings •Planting date was the main agronomic factor affecting production and water use efficiency. Compared with a late spring planting, which suffered excessive heat stress and water deficit, the late summer planting gave the highest yield and water use efficiency. •Irrigation scheduled at the late bud initial growth stage gave the highest yield and water use efficiency from the late spring and late summer plantings. Delaying irrigation to early podding resulted in a measurable increase in the amount of water unused by the crop remaining in the soil profile at crop maturity. •Plant populations of 40 plants/m2 used more water than populations of 20 plants/m2. Differences in water use efficiency between populations were not significant. •Mungbean water use was reduced under conditions of high evaporative demand. •Stressed plants (November planting) used less water in vegetative phase and more in reproductive phase. •Where adequate soil was available (February planting), mungbean used almost equal amounts of water both in vegetative and reproductive phases. •Water extraction was highest at a depth of 55–75 cm of the soil profile for both spring and summer planting dates; consistent at crop populations of 20 plants/m2 and 40 plants/m2.