Cover crops affect the partial nitrogen balance in a maize-forage cropping system

Rocha, Kassiano; Souza, Murilo; Almeida, Danilo; Chadwick, David; Jones, Davey; Mooney, Sacha

Abstract

Part of the nitrogen (N) fertilizer applied to crops is lost to the environment, contributing to global warming, eutrophication, and groundwater contamination. However, low N supply stimulates soil organic N turnover and carbon (C) loss, since the soil N/C ratio in soil is quasi-constant, ultimately resulting in land degradation. Grasses such as ruzigrass (Urochloa ruziziensis) grown as winter pasture or a cover crop in rotation with maize (Zea mays) can reduce N leaching, however, this may induce N deficiency and depress yields in the subsequent maize crop. Despite the potential to decrease N loss, this rotation may negatively affect the overall N balance of the cropping system. However, this remains poorly quantified. To test this hypothesis, maize, fertilized with zero to 210?kg?N?ha?1, was grown after ruzigrass, palisade grass (Urochloa brizanta) and Guinea grass (Pannicum maximum), and the N inputs, outputs and partial N balance determined. Despite the intrinsically poor soil quality associated with the tropical Ultisol, maize grown after the grasses was efficient in acquiring N, resulting in a negative N balance even when 210?kg?ha?1 of N was applied after Guinea grass. Losses by leaching, N2O emission and NH3 volatilization did not exceed 13.8?kg?ha?1 irrespective of the grass type. Despite a similar N loss among grasses, Guinea grass resulted in a higher N export in the maize grain due to a higher yield, resulting in a more negative N balance. Soil N depletion can lead to C loss, which can result in land degradation.

Citation

Rocha, K., Souza, M., Almeida, D., Chadwick, D., Jones, D., & Mooney, S. (2020). Cover crops affect the partial nitrogen balance in a maize-forage cropping system. Geoderma, 360, 114000. https://doi.org/10.1016/j.geoderma.2019.114000

• Journal Article Type: Article
• Acceptance Date: Oct 4, 2019
• Online Publication Date: Nov 7, 2019
• Publication Date: Feb 15, 2020
• Deposit Date: Oct 7, 2019
• Publicly Available Date: Nov 8, 2020
• Journal: Geoderma
• Print ISSN: 0016-7061
• Electronic ISSN: 1872-6259
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 360
• Article Number: 114000
• Pages: 114000
• DOI: https://doi.org/10.1016/j.geoderma.2019.114000
• Keywords: Cropping system; tropical forage; Nitrogen balance; Nitrogen loss; Nitrogen volatilization
• Public URL: https://nottingham-repository.worktribe.com/output/2773086
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S001670611931434X