Reducing nitrogen fertilization rate in spring wheat-pea rotation sustains spring wheat yield and quality

Authors: Sainju, Upendra; PRADHAN, GAUTAM - North Dakota State University

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/24/2025
Publication Date: 7/26/2025
Citation: Sainju, U.M., Pradhan, G. 2025. Reducing nitrogen fertilization rate in spring wheat-pea rotation sustains spring wheat yield and quality. Agronomy. 15(8):1806. https://doi.org/10.3390/agronomy15081806.
DOI: https://doi.org/10.3390/agronomy15081806

Interpretive Summary: Nitrogen fertilizer is one the most expensive inputs for crop production. Higher rates of nitrogen fertilization beyond crops' need not only waste nitrogen fertilizer, but also can have serious negative repercussions on soil health and environmental quality. ARS researcher in Sidney, MT in collaboration with North Dakota State University evaluated spring wheat growth, yield, and quality as influenced by four cropping sequences and four nitrogen fertilization rates in dryland cropping systems for eight years in eastern MT. They reported that nitrogen fertilization rate can be reduced by half by using spring wheat-pea rotation without compromising spring wheat grain yield and test weight compared to using continuous spring wheat with recommended or higher nitrogen fertilization rates. However, nitrogen fertilization rate can be increased to increase protein concentration in this cropping sequence. Although spring wheat growth, yield, quality were superior using spring wheat-fallow rotations compared to spring wheat-pea rotation with or without nitrogen fertilization, they did not recommend these practices due to their adverse impacts on annualized yield and soil and environmental quality. Producers can use half of the recommended nitrogen fertilization rate by using spring wheat-pea rotation for spring wheat production while sustaining grain yield and test weight.

Technical Abstract: Benefits of pea (Pisum sativum L.) in rotation with spring wheat (Triticum aestivum L.) to reduce N fertilization rates and sustain wheat growth, yield, and quality need further exploration. We examined the response of dryland spring wheat growth, yield, and quality to four cropping sequences and four N fertilization rates from 2012 to 2019 in the northern Great Plains. Cropping sequences were conventional till spring wheat-fallow (CTWF), no-till spring wheat-fallow (NTWF), no-till spring wheat-pea (NTWP), and no-till continuous wheat (NTCW), and N fertilization rates to spring wheat were 0, 50, 100, and 150 kg N ha-1. Plant density and straw yield were greater for CTWF and NTWF than NTWP and NTCW in most years. As a result, wheat grain yield and protein concentration were also greater for CTWF and NTWF than other cropping sequences at most N fertilization rates and years, except in 2015 when yield was lower. In contrast, test weight was lower for CTWF and NTWF at most N fertilization rates and years, except in 2019 when test weight was greater. Increased N fertilization rate increased grain yield linearly or nonlinearly for all cropping sequences and years. Increased N fertilization rate also increased grain protein for all cropping sequences, but had a variable effect on test weight in various years. Although grain yield and protein concentration were greater for CTWF and NTWF, spring wheat yield and test weight can be sustained by using NTWP with 50 kg N ha-1 due to rotational benefit.