Using the OVERSEER nutrient budget model to estimate on-farm greenhouse gas emissions

Abstract

The OVERSEER nutrient budget model is a farm-scale nutrient reporting and greenhouse gas (GHG) emission accounting tool used extensively throughout New Zealand (NZ) by farmers, farm consultants and fertiliser representatives. The model is increasingly being used as a tool for implementing regional council resource management requirements to limit nitrogen (N) and phosphorus losses to waterways. NZ’s main dairy company, Fonterra, also requires dairy farmers to have a nutrient budget as part of the national Clean Streams Accord. This means that a high proportion of NZ farmers can obtain reports of their on-farm GHG emission profile. The GHG emission model is based on models and algorithms used for the NZ GHG national inventory, modified to include a wide range of on-farm management practices. The model estimates methane, nitrous oxide and carbon dioxide (CO2) emissions, and presents the results as CO2 equivalents. This paper describes the model and the benefits of combining nutrients budgets and GHG emissions into a single model. It also demonstrates the effects of management practices on a range of outputs, including N leaching and GHG emissions.

The Challenge of the Urine Patch for Managing Nitrogen in Grazed Pasture Systems

“…It is also important to Figure 5 Example of the annual distribution of urinary N return to a block of land stocked at 3.2 cows ha À1 under New Zealand conditions, based on calculations using the OVERSEER model (Wheeler et al, 2008). take account of characteristics of the urine patch that differ, say, from a fertilizer application; movement of N to depth during deposition and lateral access to nutrients by pasture outside the wetted area.…”

Arbustivas forrajeras y ácidos grasos: estrategias para disminuir la producción de metano entérico en bovinos.

“…Otras fuentes significativas de emisión de CH 4 son los pantanos naturales (21%), los cultivos de arroz (20%), pérdidas por combustión de hidrocarburos (14%), combustión de biomasa (10%), rellenos sanitarios, entre otros (Wheeler et al, 2008).…”

Nitrogen gaseous emissions from farm effluent application to pastures and mitigation measures to reduce the emissions: a review

“…In farm systems, any effluent N applications should be adjusted to take into account the N loading of the applied effluent and to match pasture requirements (Luo et al 2010). In this regard, use of a nutrient budget model, such as Overseer ® (Wheeler et al 2008), is a useful tool for assessing the sustainability of N flows within farm systems and identifying opportunities for reducing NH 3 and N 2 O emissions.…”