Site-specific design of sustainable cropping systems: Linking agronomic structure to long-term performance

Designing high-performing cropping systems requires agricultural producers to balance complex trade-offs among financial returns, resource use efficiency, and production risks. Quantitative data on the performance of specific cropping strategies can aid decisions on cropping system design, yet such performance profiles remain unavailable. Here we quantify the financial and environmental performance of diverse cropping systems in a major cropping region of eastern Australia. Using daily gridded weather data, we identify homogeneous climate zones and employ the Agricultural Production Systems Simulator (APSIM) to model 88 crop rotations across 24 locations over a 60-year period of recent climate data. Our results show that site-specific climate patterns strongly predetermine achievable outcomes, with gross margins differing by up to 34 percent between climate zones. Cropping intensities averaging 1.2 to 1.4 crops per year provided the highest gross margins and water and nitrogen use efficiency, but also amplified downside risk and crop failure, particularly in drier regions. Winter crops achieved higher average gross margins than summer crops, but also resulted in greater interannual variability. Cropping systems emphasising sorghum-chickpea or wheat-mungbean consistently performed well across all indicators. A clear trade-off was identified between cropping strategies that performed best in gross margin and nitrogen use efficiency, versus downside risk, crop failure, and water use efficiency. This study demonstrates how cropping systems modelling can generate quantitative performance profiles to support the data-driven design of sustainable cropping strategies. The proposed framework integrates qualitative system design concepts with quantitative crop modelling and is transferable to other regions where calibrated crop models are available.