Nitrogen Fertilizer and Residue Management in Dryland No‐Till Hard Red Spring Wheat

Abstract

Nitrogen may enhance wheat grain quality even when wheat yield is not increased. Nitrogen rate and placement had greater effect on grain protein than wheat yield. Side‐banding N resulted in higher grain protein than broadcasting. Residue management had no effect on wheat production. This article summarizes the results from a 1‐yr field experiment conducted at two locations in northcentral Montana. Nutrient and residue management are important aspects of dryland no‐till cropping systems that directly affect wheat (Triticum aestivum L.) production. The objectives were to assess N response of hard red spring wheat grown in dryland no‐till conditions under varied crop residue management. The effects of N application rate (0, 135, and 270 kg N ha−1) and placement (broadcast vs. side‐banded) and residue management (undisturbed vs. removed) on biomass weight and N content, Normalized Difference Vegetative Index (NDVI), grain yield, grain test weight, and protein content of hard red spring wheat were evaluated. At one of two locations, the 135 kg N ha−1 rate resulted in significantly higher yield, compared with unfertilized check, but further increase of N rate to 270 kg N ha−1 did not improve yield. There was no response of grain yield to N application rate at the second location. At one of two locations, the side‐dress N application resulted in higher wheat yield, but no statistically significant differences in yield associated with N placement was observed at the second location. Biomass N content and grain protein content were significantly affected by the N application rate at both locations. The results of this study confirm that even if wheat grain yields are not always increased with N applications, N fertilizer could still be beneficial in terms of improved grain quality (test weight and protein content).

Grain yield, quality, and spectral characteristics of wheat grown under varied nitrogen and irrigation

“…The NDVI values were found to be highly related to LAI and green biomass volume (Penuelas, Gamon, Fredenn, Merino, & Field, 1994), and thus, photosynthetic efficiency (Aparicio, Villegas, Araus, Casadesus, & Royo, 2002). In a study by Walsh (2019), wheat biomass N content responded to N fertilizer, but NDVI values did not differ among N rates, suggesting that NDVI may be more sensitive to the amount of biomass than to N content of that biomass. Hashemi and Chenani (2011) reported a strong positive relationship between NDVI and SPAD values.…”