Prediction of nitrogen fertilizer requirement with the HRI WELL-N computer model

Abstract

HRI WELL-N can predict crop nitrogen requirements for a wide range of agricultural and horticultural crops. The amount of nitrogen available to the crop depends on many factors including soil type and structure, temperature, local weather conditions, leaching, etc, while the crop's actual requirement is dependent on its growth and the efficiency with which the individual plant root system is able to take up the nitrogen from the soil. A dynamic simulation model was developed to gain a greater understanding of the processes affecting crop nitrogen requirement and soil supply. More recently a user-friendly version was developed, WELL-N, capable of providing fertilizer recommendations with input data readily available to growers. The reliability of the model and its subroutines have been tested by comparing predicted values with actual data obtained from a wide range of field crops grown in the UK and Northern Europe. WELL-N calculates the nitrogen fertilizer requirements for most field crops grown in the UK, together with the likely final nitrogen content of the crop and the amount of nitrate which could potentially be leached into groundwater from specific fertilizer applications.