Response of four grain legumes to water stress in south-eastern Queensland. III. Dry matter production, yield and water use efficiency

Abstract

Dry matter production, yield and water use efficiency of soybean (Glycine max), black gram (Vigna mungo), green gram (V. radiata) and cowpea (V. unguiculata) under irrigated, rain-fed fallowed and rain-fed double-cropped culture were evaluated at Dalby in south-east Queensland. Differential species responses to cultural treatments were related to strategies of growth and water use in response to water stress. The major effect of differences between strategies related to differences in the short term rate of soil water use, which together with the seasonal pattern of water availability influenced both the total, and seasonal pattern of water use. Regardless of strategy adopted, dry matter production was primarily a function of water use. However, seed yield and water use efficiency for seed yield depended on the seasonal pattern of water use. The relative agronomic success of the various strategies therefore depended on the seasonal profiles of water availability. Some implications of the differences in stress response strategy for adaptation of these species to agricultural environments are discussed.