Farmers around New Zealand now have access to robust research into improving water quality while while wintering sheep on their lands.  

NZ Landcare Trust’s project ‘Understanding the benefits of sheep winter grazing’ examined grazing practices to see the impact on contaminants in nearby waterways. It pinpointed Critical Source Areas (CSAs) where overflow water accumulates, such as gullies, and compared the effects of leaving these areas in grass against CSAs sown in crop and actively grazed. 

AgResearch conducted the research that was funded by the Ministry for Primary Industries with sponsorship from Beef and Lamb NZ, Ballance AgriNutrients, Horizons Regional Council, Greater Wellington Regional Council, Otago Regional Council and Environment Southland. 

Over three winters between May 2020 and December 2022 the research team tested two paddocks near Waitahuna in Otago, comparing standard good management practice (as a control) of grazing crop versus retaining a grass critical source area. 

The researchers found that where CSAs were left ungrazed there were significantly fewer contaminant losses than when retained in crop and grazed. The water samples showed half the amount of phosphorus, sediment and E.coli compared to the control groups. 

“This is the first time we have had data specific to the impact of sheep winter grazing. Winter grazing is known to make a significant contribution to total losses of contaminants transported from land to water. Until now though, very little information was available that documents losses when sheep are used to graze these crops,” says Nicole Foote, Regional Coordinator for Otago at NZ Landcare Trust.

“The research provides invaluable information for farmers looking to improve their land management practices and minimise environmental risk. We now know categorically that critical source areas left in grass and ungrazed provide a buffer that reduces the potential impacts of intensive winter grazing activities on water quality.”

NZ Landcare Trust has published a series of reports and video.