Recent studies have established farm-scale features where livestock congregate as ‘hot-spots’ of emissions of the powerful greenhouse gas, nitrous oxide (N2O). Cattle urination density correlates with time spent at a location resulting in the non-homogenous distribution of nutrients deposited within excreta. Increased livestock traffic can also result in elevated levels of soil compaction leading to potentially favourable edaphic conditions for losses of nitrogen from the agricultural system. Farm-scale N2O emission hot-spots may represent economically attractive areas for targeted nitrification inhibitor application, as the inhibitor could be applied over a relatively small area, minimising costs associated with quantity of product required and labour associated with application to soil. There are limited studies, however, investigating the efficacy of nitrification inhibitors within such areas.
This project will:
- establish factors influencing N2O emissions and DMPP performance in soils with a history of high livestock impact (Obj. 1)
- determine if the microbial N-cycling community is functionally distinct in areas of soil with a history of high livestock impact compared to standard areas of pasture (Obj. 2)
- determine spatially appropriate N turnover rate constants and urine patch emission factors, with and without DMPP, in hot-spot feature soils (Obj. 3)
- model paddock and farm scale implications and conduct a cost-benefit analysis of a targeted DMPP mitigation strategy (Obj. 4).
Click on the links within the graphical summary to explore the approaches being undertaken to achieve our project goals.