Nitrogen and potassium fertilization in no-till hard red spring wheat production

Abstract

There is a need to develop more efficient nutrient management strategies to maximize wheat (Triticum aestivum L.) grain yields and increase grain protein levels. Urea, most widely used N fertilizer, is susceptible to substantial losses, resulting in low nitrogen use efficiency (NUE). This study assessed the effect of N and K fertilization on hard red spring wheat production under dryland no-till conditions in Montana. A field experiment was conducted during one growing season at two locations in Northcentral Montana. Fertilizer N was applied as urea (46–0–0) or as a urea–KCl (50:50 blend) at planting to achieve two target N rates, 135 and 270 kg N ha−1. Biomass weight, N content, and sensor-based Normalized Vegetative Difference Index (NDVI), yield, test weight, and grain protein content of wheat was evaluated. Results indicated that: (a) N may increase wheat grain quality (protein content) even when wheat yield is not increased, (b) KCl application, along with N, may result in greater wheat biomass production and grain protein values, and (c) NDVI may be more sensitive to the amount of produced biomass than to N content of that biomass. In conclusion, even if yield response to N is minimal, N is beneficial for improving grain protein content of wheat. Addition of KCl along with N may produce greater wheat biomass and increase biomass N content. The NDVI may be more sensitive to the amount of produced biomass than to its N content.