Ammonia and nitrous oxide emissions from farm effluent application to grazed pastures
Increasing demand for dairy and meat products world is encouraging countries, such as New Zealand to intensify agricultural production, thus resulting in production ofrnore effluents on farm which need to be recycled back to land for s ustainable manage ment.Environ mental concems associated with the land application of effluents encompass all aspects of non-point source pollution.Potential losses of nitrogen (N) from land application of effluents include gaseous emissions, especially ammonia (NH3) and nitrous oxide (N2O) losses.In this review paper, the extent of the NH3 and N2O losses resulting from application of effluents to pastoral soils is assessed.Nitrogen from applied effluent to pastoral soil as NH3 and N2O ranged from 1 to 45% and 0.1 to 3 % of the applied N, respectively.With improved understanding of the processes governing NH3 and N2O losses, and the soil and climatic conditions controlling NH3 and N2O emissions, a number of management options can be identified to reduce these N losses from effluent applications to grazed pastures.The exttent of these gaseous emissions depends on complex interactions between effluent characteristics, soil properties, climatic factors and agricultural practices.The mitigation options discussed in this paper are: reducing livestock numbers, lowering the amount of N excreted in effluent by using low-N feed supplements as an alternative to fertiliser N-boosted grass; using N process inhibitors that inhibit the conversion of urea to ammonium (NH4+) and NH4+ to nitrate (NO3-) in soil; optirnising timing of effluent application close to the time the nutrients are needed by the crop; ensuring quick and effective mixing with soil to minimise losses of NH3 and N2O during application; applying the effluent at rates that match plant uptake thereby avoiding excessive effluent application.Future research needs to focus on evaluating gaseous emissions accurately on a regional and national scale based on available climatie data, soil types and grazing animals and their excretal N inputs and improving model approaches to quantify the NH3 and N2O losses from effluent application with greater certainty.
Ammonia Nitrous oxide Farm dairy effluent Manure Inhibitors
J.Li Y.Shi J.Luo A.Ghani D.Houlbrooke
AgResearch,Ruakura,Private Bag 3123,Hamilton 3240,New Zealand Institute of Applied Ecology,Chinese A Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,Liaoning,China, AgResearch,Ruakura,Private Bag 3123,Hamilton 3240,New Zealand
国际会议
浙江嘉兴
英文
224-235
2013-10-24（万方平台首次上网日期，不代表论文的发表时间）