Effects of nitrogen fertilizer on the yield and protein content of wheat grown under different cropping rotations

Abstract

The effect of nitrogen fertilizer on the yield and grain protein content of several cultivars of wheat grown under wheat-fallow and wheat-pasture-pasture-fallow rotations was studied in the Victorian Mallee during 1962 to 1965. Nitrogen fertilizer increased whest yield on the wheat-fallow rotation, but had little effect on the wheat-pasture-pasture-fallow rotation. Changes in grain protein content due to nitrogen fertilizer were small compared with changes due to the type of cropping rotation. Climate had relatively little influence on grain protein content despite marked variability in rainfall. The significance of this result is discussed in relation to a correlation established between grain protein content of unfertilized plots and yield response to applied nitrogen. The performance of the wheat cultivars Insignia, Olympic, and Beacon with and without applied nitrogen was similar under both rotations.