Prediction of weather damage of mungbean seed in tropical Australia. II. Model application

Abstract

To demonstrate a model to simulate the risk of weather damage of mungbean, application studies were undertaken using 27 years of climatic data collected at Katherine, Northern Territory, Australia. In terms of the risk of weather damage, the transition from high risk to low risk occurred after mid-February but before 20 March. High quality seed could be expected in 70% of seasons for a crop that matured after 20 March. For planting dates prior to 25 January, the chance of producing premium quality seed was enhanced to 40–70% of seasons by sowing a cultivar that matured 2 weeks later and by harvesting promptly (4 days after maturity). There was no benefit from later maturity or harvest promptness where sowing was made after 25 January, because maturity occurred after the wet season was complete. In contrast, yield was optimised at early January sowing dates. Calculating gross margins by combining yield and weather damage simulations identified an optimum sowing date between the optimum for yield and seed quality. It was shown that later maturity combined with photoperiod sensitivity increased the sowing window from 10 to 29 days compared with a short duration variety that was insensitive to photoperiod. The relative merits of modelling and field experimentation in assessing the cropping potential for mungbean in a new region are discussed. The need to be able to simulate the yield of the second flush of flowers was acknowledged as a future research requirement.