AgResearch is the host of the NZAGRC and is New Zealand's largest centre for pastoral agriculture research and development.
AgResearch includes teams of researchers with skills relevant to the Centre in rumen function, rumen microbiology, ruminant physiology, soil science, environmental science, agricultural systems management, forage plant growth and development, on-farm practice change, social science, technology uptake, genomics, proteomics and metabolomics of animals, plants and microorganisms.
Nitrous oxide emissions from cattle urine deposited onto soil supporting a winter forage kale crop
van der Weerden, T. J., T. M. Styles, et al. (2017). "Nitrous oxide emissions from cattle urine deposited onto soil supporting a winter forage kale crop." New Zealand Journal of Agricultural Research 60(2): 119-130.
Wintering cows on forage crops leads to urine being excreted onto wet, compacted soils, which can result in significant emissions of nitrous oxide (N2O). A field trial was conducted to determine the N2O emission factor (EF3; proportion of urine-N lost as N2O-N) for dairy cows wintered on a kale forage crop on a poorly drained soil. Urine was collected from non-lactating dairy cows on a forage kale diet and applied at 550 kg N ha−1 to artificially compacted soil to simulate trampling and non-compacted soil in a kale field. Cumulative N2O losses over four months were 7.38 and 2.64 kg N2O-N ha−1 from urine applied to, respectively, compacted and non-compacted soil. The corresponding EF3 values 0.75% and 0.30%, respectively, differed (P = .003) due to compaction. Combining our results with previous studies, where brassica-fed livestock urine was applied to soils supporting a forage brassica crop, suggested a significant relationship between soil water-filled pore space (WFPS) and brassica-derived urine EF3 (P = .005).
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