Item

A synergistic mitigation technology for nitrate leaching and nitrous oxide emissions for pastoral agriculture

Di, Hong J.
Cameron, Keith C.
Roberts, A.
Date
2012
Type
Conference Contribution - published
Fields of Research
ANZSRC::0503 Soil Sciences , ANZSRC::0703 Crop and Pasture Production
Abstract
In grazed grassland, most of the nitrate (NO3-) leaching and nitrous oxide (N2O) emissions come from the animal urine-N returned to the pasture by the animal during outdoor grazing (Di and Cameron, 2002a). The N loading rate under a dairy cow urine patch in intensively grazed dairy grassland can be as high as 1000 kg N ha-1 (Di and Cameron 2002a). Most of the N in the urine is urea which, when deposited onto the soil, is oxidized to ammonium (NH4+), and then to NO3 -. The excess NO3- remaining after plant uptake or immobilisation is prone to leaching during the wet season or lost as N2O. Here we present a mitigation technology that is synergistic in decreasing both NO3- leaching and N2O emissions, while at the same time, increasing pasture production. The mitigation technology involves the use of a nitrification inhibitor, dicyandiamide (DCD), to treat grazed pasture soil.