Abstract：
Rice is the staple food in Sri Lanka, and over 15% of the national land is allocated for rice cultivation. Greenhouse gas (GHG) emissions from rice fields account for 10% of national GHG emissions. The country has committed to reducing its emissions by 14.5% between 2010 and 2030 and achieving net zero emissions by 2060. In 2021, the country banned agro-fertilizer imports and opted for organic fertilizers, leading to a notable decrease in production and posing challenges to food security. However, the impact of adopting compost fertilizers alone remains unexplored. This study evaluated the global warming impact of two organic fertilizer strategies: switching to compost fertilizer instead of urea and applying rice straw compost instead of retaining crop residue. We applied the Denitrification and Decomposition model (DNDC 95) to rice field management data from Sri Lanka\'s Mahaweli H agricultural region. Simulations suggest that both strategies would increase the global warming potential of rice fields, mainly owing to elevated N2O emissions. This outweighs the mitigation benefits of avoiding crop residue retention and adding organic carbon through compost. Overall, our results point to the potential risk of shifting exclusively to compost-based fertilizers.
摘要：
大米是斯里兰卡的主食，全国15%以上的土地用于水稻种植。稻田温室气体(GHG)排放量占全国温室气体排放量的10%。该国承诺在2010年至2030年之间将其排放量减少14.5％，并在2060年之前实现净零排放。2021年，该国禁止进口农业肥料，并选择了有机肥料。导致产量显著下降，并对粮食安全构成挑战。然而,单独采用堆肥肥料的影响仍未被探索。这项研究评估了两种有机肥料策略对全球变暖的影响：改用堆肥肥料代替尿素，以及使用稻草堆肥代替保留作物残留物。我们将反硝化和分解模型（DNDC95）应用于斯里兰卡MahaweliH农业区的稻田管理数据。模拟表明，这两种策略都会增加稻田的全球变暖潜力，主要是由于N2O排放量增加。这超过了避免作物残留和通过堆肥添加有机碳的缓解益处。总的来说,我们的研究结果指出了完全转向堆肥肥料的潜在风险.
