RESPONSE OF WINTER-WHEAT TO N-FERTILIZER - DYNAMIC-MODEL

A concise computer simulation model is described for calculating the growth and N-content of winter-wheat. The validity of the model was tested by means of a new application of statistical theory against the results of nationwide fertiliser experiments having different designs. There was agreement within the limits of experimental error between the measured and simulated values of both total plant and of grain dry weight over the entire range of N-fertiliser treatments in the different experiments. The model also gave good estimates of the %N in the grain provided N-fertilizer levels were not high. Response curves, calculated from the model for yield, grain %N, are given for different combinations of potential yield, mineralisation rate and the distribution of inorganic-N down the soil profile.