Redesigning Soil Nitrogen Management to Stop The Leaks
Lincoln University Dairy Farm has high-tech monitoring of its environment, water and pollution. Last year it got together with Ravensdown for the commercial release of eco-n, a nitrification inhibitor, which slows up the loss of nitrogen compounds through the soil profile and the loss of nitrous oxide to the air.
The eco-n is applied as a spray twice a year (in spring and autumn) and it slows the action of soil bacteria, which do the nitrification. This means that nitrogen, particularly in animal urine patches, stays in the soil for longer and can be used by the pasture plants in the spring so farmers may be able to use less fertiliser particularly in the spring.
Two other fertiliser companies, Ballance and Summit-Quinphos, are also marketing nitrogen fertilisers with nitrification and urease inhibitors, but the Lincoln-Ravensdown product is the market leader and has the longest research history. It is being trialled at sites throughout the country Canterbury, Taupo, Manawatu and Waikato.
Professor Keith Cameron, Lincoln University Soil Science, says he had plenty of research history on inhibitors, over five or six years, and the results are consistently good. Costs to farmer of two applications are a total of $124/ha applied.
Cameron says the product stops 60% of leaching loss and 75% of NO emissions. Returns include 20% more pasture growth after applications and 10-15% DM gain across whole year.
Ravensdowns initial release last year resulted in about 17,000ha being treated.
The application of nitrification inhibitor eco-n to improve the efficiency of the nitrogen cycle reduces the environmental effects of dairying and improves profitability. It is a good example of the redesigning of farm systems which Parliamentary Commissioner for the Environment, Dr Morgan Williams, requested in order to combat growing problems with nitrogen and water use resulting from the intensification of agriculture (Growing for Good, November 2004).
Cow urine is a major source of ammonium, which results in 90% of nitrate leaching and 75% of agricultural nitrous oxide emissions. Eco-n slows down the nitrification process when the nitrosomonas bacteria convert ammonium to nitrate. Eco-n can reduce nitrification by 60%, making more nitrogen available to plants and thereby reducing the need for applications of nitrogenous fertilisers.
Whole paddock measurements under dairy grazing suggest annual production lifts of 10% to 15% are likely to occur. Up to 20% more pasture has been measured during after spring applications.
Eco-n applications as directed in autumn and spring have a cost of $124/ha applied, and provide extra pasture at a cost of 6-10c/kg DM. By comparison, more urea has been costed at 10-15c/kg DM. At a payout of $4.00 / kg milksolids, and a typical conversion ratio of 15 kilograms drymatter per kilogram milksolids, a 10% increase in pasture production provides an additional $223 / hectare net income. This is a return on investment of around 180%. An extra 15% of pasture would generate a return on investment of 320%. Eco-n should be applied to recently grazed pasture in fine particle suspension form to ensure even coverage. Some 10mm of rainfall or irrigation is needed to wash the product into the soil.
The product is supplied by Ravensdown on a per hectare applied basis using approved operators. The accurate recording of where all product is applied also allows further studies on a regional and national basis in relation to the environmental benefits, particularly for greenhouse gas inventory calculations.
The eco-n is applied as a spray twice a year (in spring and autumn) and it slows the action of soil bacteria, which do the nitrification. This means that nitrogen, particularly in animal urine patches, stays in the soil for longer and can be used by the pasture plants in the spring so farmers may be able to use less fertiliser particularly in the spring.
Two other fertiliser companies, Ballance and Summit-Quinphos, are also marketing nitrogen fertilisers with nitrification and urease inhibitors, but the Lincoln-Ravensdown product is the market leader and has the longest research history. It is being trialled at sites throughout the country Canterbury, Taupo, Manawatu and Waikato.
Professor Keith Cameron, Lincoln University Soil Science, says he had plenty of research history on inhibitors, over five or six years, and the results are consistently good. Costs to farmer of two applications are a total of $124/ha applied.
Cameron says the product stops 60% of leaching loss and 75% of NO emissions. Returns include 20% more pasture growth after applications and 10-15% DM gain across whole year.
Ravensdowns initial release last year resulted in about 17,000ha being treated.
The application of nitrification inhibitor eco-n to improve the efficiency of the nitrogen cycle reduces the environmental effects of dairying and improves profitability. It is a good example of the redesigning of farm systems which Parliamentary Commissioner for the Environment, Dr Morgan Williams, requested in order to combat growing problems with nitrogen and water use resulting from the intensification of agriculture (Growing for Good, November 2004).
Cow urine is a major source of ammonium, which results in 90% of nitrate leaching and 75% of agricultural nitrous oxide emissions. Eco-n slows down the nitrification process when the nitrosomonas bacteria convert ammonium to nitrate. Eco-n can reduce nitrification by 60%, making more nitrogen available to plants and thereby reducing the need for applications of nitrogenous fertilisers.
Whole paddock measurements under dairy grazing suggest annual production lifts of 10% to 15% are likely to occur. Up to 20% more pasture has been measured during after spring applications.
Eco-n applications as directed in autumn and spring have a cost of $124/ha applied, and provide extra pasture at a cost of 6-10c/kg DM. By comparison, more urea has been costed at 10-15c/kg DM. At a payout of $4.00 / kg milksolids, and a typical conversion ratio of 15 kilograms drymatter per kilogram milksolids, a 10% increase in pasture production provides an additional $223 / hectare net income. This is a return on investment of around 180%. An extra 15% of pasture would generate a return on investment of 320%. Eco-n should be applied to recently grazed pasture in fine particle suspension form to ensure even coverage. Some 10mm of rainfall or irrigation is needed to wash the product into the soil.
The product is supplied by Ravensdown on a per hectare applied basis using approved operators. The accurate recording of where all product is applied also allows further studies on a regional and national basis in relation to the environmental benefits, particularly for greenhouse gas inventory calculations.