Nitrogen fertilizer rate and time effect on dryland no‐till hard red spring wheat production

Abstract

Abstract Increasing the efficiency of wheat (Triticum aestivum L.) production is vital for Montana growers’ sustainability and competitiveness in the market. Nitrogen fertilizer applications at the right rate and time in the growing season are important for optimizing wheat grain yield and quality. Two dryland field experiments were conducted in North Central Montana in 2014. The effects of N fertilizer rates (28, 84, and 140 kg N ha−1) and application times (seeding, tillering, jointing, and flag leaf emergence) on grain yield, test weight, protein content, protein yield, grain N uptake, and N use efficiency (NUE) were evaluated. Wheat grain yield and protein content was the highest with N fertilizer applied at 140 kg N ha−1 rate at tillering. Delaying N fertilizer until flag leaf resulted in significantly lower wheat yields and grain protein values. It is possible that higher N rates would have allowed to maximize both yield and protein content. Nitrogen use efficiency was the highest with N fertilization at tillering and jointing. Nitrogen response trials coupled with historical yield records did not provide accurate estimates of optimum N rates. Close monitoring of crop nutrient status throughout the growing season (using destructive sampling and/or crop sensors), coupled with appropriate preplant soil testing, and splitting N applications to tailor N supply with crop demand should help to improve NUE.