Plant tissue tests for predicting nitrogen fertilizer requirements in spring wheat

Abstract

Application of nitrogen (N) at sowing (basal N) alone is not always adequate for maximum yield and quality formation in wheat (Triticum aestivum L.). Because uptake and utilization ofN by the plant is influenced by many environmental and varietal factors, supplementary N may be needed during the growing season, too. Additional N can be applied at particular stages of the plant’s development (phenology) to produce the best result from its use. The applicability of plant tissue N concentration as a diagnostic tool for measuring the N status of a wheat stand to guide economical use of additional N application was reviewed here. On the basis of grain protein concentration data, growers producing spring wheat with consistently low protein concentration are advised to pursue a more vigorous and better planned N fertilization programme in their crops. Plant tissue N testing provides a useful method for the producer to annually optimize wheat grain yield and grain protein concentration. Knowledge of both these ‘critical components’ as determined by pre-harvest N levels of plant tissue and post-harvest grain protein concentration can be utilized for making both basal and supplemental N fertilizer recommendations.