Prediction of the influence of water, sowing date and planting density on dry matter production of wheat

Abstract

A water balance model was used to calculate dry matter yields for wheat. The prediction used initial soil water, irrigation, rainfall and pan evaporation as inputs. Leaf area index (LAI) was estimated by an empirical equation and changes in LAI were determined by the ratio of predicted to potential transpiration and relative density. Time of sowing influenced time of maximum LAI. Dry matter production was calculated from equations relating LAI and photosynthesis. The model was tested with data from wheat crops in South Australia which had been grown with large differences in water supply, planting density and sowing date between seasons. There was good agreement between predicted and measured production.