Next Article in Journal
Reported Acquisition Practices of Australian Dog Owners
Previous Article in Journal
Parasites in Horses Kept in A 2.5 Year-Round Grazing System in Nordic Conditions without Supplementary Feeding
Open AccessArticle

Benefits and Trade-Offs of Dairy System Changes Aimed at Reducing Nitrate Leaching

1
DairyNZ Ltd., Private Bag 3221, Hamilton 3240, New Zealand
2
AgResearch, Grasslands Research Centre, Palmerston North 4410, New Zealand
3
AgResearch, Invermay Agricultural Centre, Mosgiel 9053, New Zealand
4
DairyNZ Ltd., Canterbury Agriculture & Science Centre, Lincoln 7608, New Zealand
5
AgResearch, Lincoln Research Centre, Lincoln 7674, New Zealand
*
Author to whom correspondence should be addressed.
Animals 2019, 9(12), 1158; https://doi.org/10.3390/ani9121158
Received: 13 November 2019 / Revised: 9 December 2019 / Accepted: 12 December 2019 / Published: 17 December 2019
(This article belongs to the Section Animal System and Management)
Reducing inputs of nitrogen fertiliser and purchased feed, with an associated reduction in stocking rate on pastoral dairy farms resulted in less nitrate leaching. A co-benefit was a reduction in greenhouse gas emissions. The exception was the implementation of a wintering barn where nitrate leaching was reduced, but greenhouse gas emissions remained unchanged due to greater manure storage and handling. Emission reductions in the lower-input systems came at an average loss of profit of approximately NZ$100 per tonne CO2-equivalent.
Between 2011 and 2016, small-scale farm trials were run across three dairy regions of New Zealand (Waikato, Canterbury, Otago) to compare the performance of typical regional farm systems with farm systems implementing a combination of mitigation options most suitable to the region. The trials ran for at least three consecutive years with detailed recording of milk production and input costs. Nitrate leaching per hectare of the milking platform (where lactating cows are kept) was estimated using either measurements (suction cups), models, or soil mineral nitrogen measurements. Post-trial, detailed farm information was used in the New Zealand greenhouse gas inventory methodology to calculate the emissions from all sources; dairy platform, dairy support land used for wintering non-lactating cows (where applicable) and replacement stock, and imported supplements. Nitrate leaching was also estimated for the support land and growing of supplements imported from off-farm using the same methods as for the platform. Operating profit (NZ$/ha/year), nitrate leaching (kg N/ha/year), and greenhouse gas emissions (t CO2-equivalent/ha/year) were all expressed per hectare of milking platform to enable comparisons across regions. Nitrate leaching mitigations adopted in lower-input (less purchased feed and nitrogen fertiliser) farm systems reduced leaching by 22 to 30 per cent, and greenhouse gas emissions by between nine and 24 per cent. The exception was the wintering barn system in Otago, where nitrate leaching was reduced by 45 per cent, but greenhouse gas emissions were unchanged due to greater manure storage and handling. Important drivers of a lower environmental footprint are reducing nitrogen fertiliser and purchased feed. Their effect is to reduce feed flow through the herd and drive down both greenhouse gas emissions and nitrate leaching. Emission reductions in the lower-input systems of Waikato and Canterbury came at an average loss of profit of approximately NZ$100/t CO2-equivalent (three to five per cent of industry-average profit per hectare). View Full-Text
Keywords: greenhouse gases; operating profit; mitigations; New Zealand; environmental footprint greenhouse gases; operating profit; mitigations; New Zealand; environmental footprint
MDPI and ACS Style

Beukes, P.; Romera, A.; Hutchinson, K.; van der Weerden, T.; de Klein, C.; Dalley, D.; Chapman, D.; Glassey, C.; Dynes, R. Benefits and Trade-Offs of Dairy System Changes Aimed at Reducing Nitrate Leaching. Animals 2019, 9, 1158.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop