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
• Contract Date: Oct 7, 2019