Jo Kerslake Dawn Dalley Miranda Hunter

Understand your nutrient budget

A recent paper shows that there is no single solution for reducing nitrogen, phosphorus, and sediment losses to meet standards met by regional councils.

DairyNZ scientist Dawn Dalley recently spoke at a South Island Dairy Event workshop, emphasising the need for farmers to understand their nutrient budgets and determine the consequences before making changes.

The paper was prepared by Dawn Dalley and Ina Pinxterhuis of DairyNZ, Miranda Hunter of Roslin Consultancy Southland, and Joanne Kerslake of AbacusBio.

"The options available to individual farmers need to be assessed against overall farm performance and efficiency, and tailored to meet the goals of continued business viability and improved water quality for their particular farm and region," Dawn says.

 "Nitrogen losses mainly occurred from animal urine patches and wintering cows on crops with a high nitrogen content had a high risk of nitrogen loss due to stocking densities in the crop paddock."

Dawn says building feedpads and wintering barns is not a quick-fix solution.

"In a study in the horizons catchment, the incorporation of a free-stall barn reduced nitrogen leaching by 34%."

"However, a 17% increase in cow numbers and a 71% increase in milk solids production were required to cover the cost of the winter facility."

"Under the intensified scenario the nitrogen leaching returned to the level predicted prior to the capital investment in the barn and so resulted in no environmental benefit."

"Whatever you choose to do, do your homework first and don't rush any decision. There will seldom be one thing that you can change to meet the new targets."

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Photo credits to NZX Agri