Soyabean ( Glycine max) yields from non-irrigated fields in the mid-southern USA have consistently lagged behind those from irrigated fields. Nonetheless, non-irrigated fields still attract a larger share of soyabean acreage in this region. This is likely due to various irrigation constraints, which include land leasing arrangements, water shortage, lack of management time and low levels of operating capital. The objective of this study was to identify production system components consisting of tillage, cultivar selection and planting date strategies for a soil series that are most suitable for enhancing economic returns to dryland soyabean. Data from field experiments in three locations in Arkansas, USA during 1995 and 1996 were used for the study. Leading production systems were identified on the basis of their net returns. Results of the study showed that the performance of the production systems in terms of crop yields and net returns is influenced by the location and production year. While the evidence on pure planting date effects was confounded with physical field location, cultivar yields from early soyabean plantings in April and May were generally higher than those from later plantings. Furthermore, conventional and fallow production systems had higher net returns than no-till systems, largely due to higher herbicide costs associated with no-till systems. Sensitivity analysis showed that planting date and seedbed preparations are robust to changes in herbicide, fuel and soyabean prices. Further, careful attention to cultivar selection is deemed appropriate because cost differences of cultivar seeds are minor relative to net return differences that are yield driven.
