科研之友
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摘要
Sugarcane is an important crop in the tropics and sub-tropics and its production requires very high rates of nitrogen (N) fertiliser. This N use, together with the warm, wet environment in which it grows, produces a high potential for emissions of the greenhouse gas nitrous oxide (N(2)O) from soils. The few measurements of N(2)O emitted from sugarcane are higher than expected from the level of N applied or experience in other crops. Accordingly, we simulated long-term N(2)O emissions over a range of environments and sugarcane management practices. Simulations were undertaken with the cropping systems model, APSIM, after we (1) tested the denitrification sub-model and (2) added a mechanistic N(2)O prediction capability to the model. Predicted N(2)O emissions agreed well with data from two field experiments measured, provided the default value of the model's denitrification rate coefficient was substantially increased. We predict N(2)O emissions from soils in Australian sugarcane production may commonly be equivalent to 3-5% of N fertiliser applications across a wide range of environments, including some where field studies have yet to be undertaken. As expected, predicted emissions varied between regions and soils, being higher in clay soil, where substantial irrigation was applied and where crop residues were retained. Reducing N fertiliser applications would obviously help reduce N(2)O emissions. It has been previously suggested that there is potential for substantial reductions (e.g. by 30%) in Australian sugarcane production so this is one pathway to help reduce N(2)O emissions. However, it is also important to better understand the interactions between specific site (soil and climate) and management (N fertiliser, crop residue and irrigation) factors influencing N(2)O emissions to find other opportunities to reduce emissions.
- 出版日期2010-3-15
- 单位CSIRO
