New South Wales Department of Primary Industries, 98 Victoria St, Taree, NSW 2430, Australia.
New South Wales Department of Primary Industries, Armidale Livestock Industries Centre, Trevenna Rd, Armidale, NSW 2351, Australia; School of Environmental and Rural Science, University of New England, Armidale, NSW 2531, Australia.
Sci Total Environ. 2020 Jul 10;725:138260. doi: 10.1016/j.scitotenv.2020.138260. Epub 2020 Mar 27.
Climate change threatens humanity yet the provision of food that supports humanity is a major source of greenhouse gases, which exacerbates that threatening process. Developing strategies to reduce the emissions associated with key global commodities is essential to mitigate the impacts of climate change. To date, however, there have been no studies that have estimated the potential to reduce GHG emissions associated with the production of wheat, a key global commodity, at a national scale through changes to wheat production systems. Here, we assess the consequences for net GHG emissions of Australian wheat production from applying three changes to wheat production systems: increasing the rates of fertiliser N to achieve the water-limited yield potential; increasing the frequency of lime applications on acid soils; and changing a two year cropping rotation (from wheat-wheat to legume-wheat). We predict that applying these three changes across the key wheat growing regions in Australia would increase production of wheat and legumes by 17.8 and 5.3 Mt, respectively, over the two-year period. Intensifying Australian production would reduce the need to produce wheat and legumes elsewhere in the world. This would free up agricultural land at the global scale and avoid the need to convert forestland and grassland to cropping lands to meet increasing global demands for wheat. We find that applying these changes across wheat growing zones would reduce the GHGs associated with Australian wheat production by 18.4 Mt CO-e over the two-year period. Our research supports the notion that intensification of existing agricultural production can provide climate change mitigation. The impacts of intensification on other environmental indicators also need to be considered by policy makers.
气候变化威胁着人类，但为人类提供食物是温室气体的主要来源，这加剧了这一威胁过程。制定减少与关键全球商品相关排放的战略对于缓解气候变化的影响至关重要。然而，迄今为止，还没有研究估计通过改变小麦生产系统，从国家规模上减少与生产关键全球商品小麦相关的温室气体排放的潜力。在这里，我们评估了通过三种方式改变小麦生产系统对澳大利亚小麦生产的净温室气体排放的后果：增加肥料氮的施用量以达到水分限制的产量潜力；增加酸性土壤的石灰施用量；改变两年轮作（从小麦-小麦到豆科作物-小麦）。我们预计，在澳大利亚主要的小麦种植区实施这三种变化，将使小麦和豆类的产量在两年内分别增加 178 万吨和 53 万吨。澳大利亚生产的集约化将减少在世界其他地方生产小麦和豆类的需求。这将在全球范围内腾出农业用地，并避免为了满足全球对小麦日益增长的需求而将林地和草地转换为耕地。我们发现，在小麦种植区实施这些变化将使澳大利亚小麦生产的温室气体排放量在两年内减少 1840 万吨二氧化碳当量。我们的研究支持这样一种观点，即加强现有农业生产可以为气候变化缓解提供帮助。决策者还需要考虑集约化对其他环境指标的影响。
