Publication Date
1997
Description
The objective of this two-year experiment was to determine the ability of forages grown as winter cover crops to reduce nitrate leaching losses after temporary leguminous pastures were ploughed. In both years, cover crops reduced cumulative leaching losses compared with bare fallow and were most effective when sown early in the autumn. When large amounts of residues with relatively low N concentrations were incorporated in the soil in the spring, there was extensive net N immobilisation that suppressed the yield of the following wheat test crop. When cover crops were grazed, the N consumed by sheep as herbage was returned in highly concentrated urine patch areas. However, due to small amounts of subsequent drainage, grazing did not markedly increase cumulative leaching losses in either year. Compared with incorporation, grazing of cover crops overcame any possible yield reductions of the following spring wheat test crop.
Citation
Francis, G S.; Bartley, K M.; and Tabley, F J., "Can Forages Reduce Nitrate Leaching Losses from Mixed Cropping Rotations in New Zealand?" (2024). IGC Proceedings (1997-2023). 3.
https://uknowledge.uky.edu/igc/1997/session20/3
Included in
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Can Forages Reduce Nitrate Leaching Losses from Mixed Cropping Rotations in New Zealand?
The objective of this two-year experiment was to determine the ability of forages grown as winter cover crops to reduce nitrate leaching losses after temporary leguminous pastures were ploughed. In both years, cover crops reduced cumulative leaching losses compared with bare fallow and were most effective when sown early in the autumn. When large amounts of residues with relatively low N concentrations were incorporated in the soil in the spring, there was extensive net N immobilisation that suppressed the yield of the following wheat test crop. When cover crops were grazed, the N consumed by sheep as herbage was returned in highly concentrated urine patch areas. However, due to small amounts of subsequent drainage, grazing did not markedly increase cumulative leaching losses in either year. Compared with incorporation, grazing of cover crops overcame any possible yield reductions of the following spring wheat test crop.
