Location: Agricultural Systems ResearchTitle: Nitrogen use in spring wheat affected by crop diversification, management, and tillage
|LENSSEN, ANDREW - Iowa State University|
|Jabro, Jalal "jay"|
|Stevens, William - Bart|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/25/2021
Publication Date: 4/15/2021
Citation: Allen, B.L., Lenssen, A.W., Sainju, U.M., Jabro, J.D., Stevens, W.B. 2021. Nitrogen use in spring wheat affected by crop diversification, management, and tillage. Agronomy Journal. 113(3):2437-2449. https://doi.org/10.1002/agj2.20686.
Interpretive Summary: N availability is a primary factor limiting crop productivity in semi-arid dryland cropping systems. Rotation intensity, management system, and tillage system each play a key role in the development of sustainable dryland spring wheat cropping systems. Our study showed that wheat grain production practices affected N utilization. Crop rotation and management system often impacted N relationships with wheat production, while tillage impacts differed among years. Continuously cropped spring wheat showed the least favorable N relationships, though neither the three or four year rotations offered greater N benefits above that of the two year rotation. Ecological management of spring wheat generally used N less efficiently than that under conventional management, most likely due to the delayed planting date of the ecological management practice. Differences in yield and N use of spring wheat varied significantly among years, emphasizing the need to develop management tools that optimize cropping system N uptake despite the typical highly variable precipitation patterns of the NGP.
Technical Abstract: Dryland wheat production potential in the northern Great Plains (NGP) often is limited by N availability impacted by various management practices. A 4-yr study was conducted in northeast Montana to relate spring wheat (Triticum aestivum L.) productivity and N utilization to management system (conventional and ecological), tillage (till and no-till), and four crop rotations (continuous spring wheat, spring wheat-pea [Pisum sativum L.], spring wheat-hay barley [Hordeum vulgare L.]-pea, and spring wheat-hay barley-corn [Zea mays L.]-pea. Ecological management included variable seed rates, delayed planting dates, banded N fertilizer, and increased stubble height compared to conventional management with standard seed rates and planting dates, short stubble height, and broadcast N fertilizer. Continuous spring wheat showed the lowest grain yield, with the least efficient utilization of N compared to 2, 3, and 4-yr rotations. Nitrogen-use efficiency (NUE) was 37% lower for continuous wheat than other rotations. Increasing complexity of crop rotation had little impact on wheat production or N relationships. The delayed planting date associated with ecological management of spring wheat contributed to 33% less efficient use of N compared to an early planting date with conventional management. Overall, results indicated that crop rotation and management system often impacted N relationships with wheat production, while tillage impacts differed with year. Differences in yield and N use of spring wheat varied among years, underscoring the need to refine management systems given the highly variable precipitation patterns typical of the NGP.