Abstract
A crop growth model was integrated with a geographical information system (GIS) in order to quantify the impact of local temperature variation and soil water capacity on ley production. At most, local temperature differences resulted in a 5% difference in estimated grass yields during a dry year. The yield was on average 50% lower in sandy soils compared with clay soils. As compared with a year with normal precipitation, the estimated yield was about 40% lower in sandy soils and 15–20% lower in clay soils. A combined application of crop growth models, topoclimatic information and GIS can be a useful tool in resource mapping and agricultural planning and management.