Nitrogen (N) has been an integral part of pasture management practice here in New Zealand for more than 50 years. It’s an essential nutrient for plant growth, particularly ryegrass and clover pastures.
Last year, AgResearch released a study which found even well-managed ryegrass/clover pastures remain deficient in nitrogen for much of the year, and respond to the application of nitrogen fertiliser. But response times and efficacy can vary depending on rate, timing, carry-over effect of nitrogen fertiliser, and geography/condition of the land and soil. The research found early spring is generally a better time to apply than in autumn to maximise response.
On-Farm Excellence Environment team Programme Lead, Julie Morris, says Farm Source captures data annually on nitrogen fertiliser conversion efficiency on Co-op farms.
“Simply speaking, nitrogen fertiliser conversion efficiency is how well nitrogen applied to a farm is converted to pasture and crop that’s eaten. To calculate this, we look at total nitrogen applied for a season, relative to pasture and crop harvested from the dairy platform,” she says.
“It’s about how much pasture response we get from every application of nitrogen on-farm through the season.”
Improving nitrogen conversion efficiency on-farm has lots of benefits for farmers. If farmers can get a better pasture response from the same nitrogen, that can help to increase homegrown feed and herd productivity without extra cost. Or if farmers can use less, but get the same pasture response, they can reduce their spend on fertiliser.
“As a Co-op, we’re seeing a reduction in the Purchase Nitrogen Surplus on-farm, this is the surplus pool of nitrogen at risk of being lost to the environment – either leaching to groundwater or lost as GHG emissions. Our nitrogen conversion efficiency metric is very localised and different farms have a different potential pasture yield. The Farm Insights Report provides local benchmarks with comparisons made to the 100 closest farms in an area,” Julie says.
With so many factors influencing nitrogen conversion efficiency, it is essential for farmers to assess their individual farm and identify where opportunities are.
“One of the things that supports nitrogen conversion is soil fertility and partner nutrients. There are many other factors within a farmer’s control which can affect the total pasture or crop response to nitrogen including pasture or crop type, pasture renewal and management, as well as soil health,” Julie says.
“Farmers have a good understanding around when they get the best pasture response to every nitrogen application – the underlying principles of placement and timing. But there is an opportunity to enhance this, and to assess where improvements can be made. Fertiliser companies have a lot of expertise in ensuring farmers get the maximum response to the nutrients applied, and our local Farm Source TSRs are always there to help.”
Talk to your local TSR or visit a Farm Source store to find out more.