集约经营油茶园不同施肥模式下土壤氧化亚氮排放特征研究

Nitrous oxide (N2O) is one important greenhouse gas with its global warming potential 265 times than that of carbon dioxide. Therefore, its mitigation is vital in improving nitrogen using efficiency and mitigating global climate change. Camellia oleifera is one important oil crop in China and one of the four woody oil crops around the world. The Chinese government pay a lot attention to the development of Camellia oleifera as its oil is very good to in human health. However, since Camellia oleifera is usually cultivated in red soils with low nutrient level, intensively managed practices especially intensively fertilizing turns out to be effective approach for Camellia oleifera development. As red soils are highly acidified due to the special climate in this region and by the special physiological traits of Camellia oleifera, a high load of fertilization input might enable too much soil N input and possibly more N2O emissions. However, little data was availabe on the N2O emission traits of Camellia oleifera field soil. Here, we conducted in situ monitoring study of N2O emissions from intensively managed Camellia oleifera field soil as influnced by different fertilization practices. We aimed to understand the N2O emission traits and the mechanisms accounting for the traits in Camellia oleifera field soil with different fertilization practices. Moreover, chemical nitrification inhibitors and biochar were employed in combination with each fertilization practice to identify the mitigation potential in intensively managed Camellia oleifera field undergoing different fertilization practices. The result of our study will help in the N2O emission budget and provide data for the mitigation potential evaluation of intensively managed Camellia oleifera field, which will benifit the ecological and economical development of Camellia oleifera.

氧化亚氮(N2O)是重要的温室气体之一，增温潜势为二氧化碳的265倍，其减排对提高肥料利用率和减缓气候变化意义重大。油茶是我国重要木本油料作物，国家高度重视油茶产业发展。油茶主要在红壤丘陵区经营，该地区土壤贫瘠保肥力差，油茶集约经营尤其是集约施肥成为油茶产业发展的重要途径。由于红壤酸度高，加之油茶本身也会导致土壤酸化，油茶园土壤大量施肥必然会影响土壤N2O产生，而其在不同施肥模式影响下的排放特征尚不明确。本研究拟通过对不同典型施肥模式油茶园N2O排放及其微生物学机制进行研究，同时结合使用双氰胺和黑炭进行减排，明确不同施肥模式油茶园土壤N2O排放动态和强度，阐明不同施肥模式油茶园土壤N2O排放机制及其减排潜力。据此，为红壤区集约经营油茶园土壤N2O排放清单制定和减排潜力评估提供科学依据和数据支撑，为提高油茶产业经营的生态学和经济学效益提供科学指导。

氧化亚氮(N2O)是仅次于甲烷和二氧化碳的重要温室气体，增温潜势为二氧化碳的265倍，其减排对减缓气候变化意义重大。油茶是我国重要木本油料作物，也是世界四大木本油料作物之一，国家高度重视油茶产业发展。油茶主要在红壤丘陵区经营，该地区土壤贫瘠保肥力差，油茶集约经营尤其是集约施肥成为油茶产业发展的重要途径。由于红壤酸度高，加之油茶本身也会导致土壤酸化，油茶园土壤大量施肥必然会影响土壤N2O产生，而其在不同施肥模式影响下的排放特征尚不明确。本研究通过对不同施肥模式油茶园N2O排放及其微生物学机制进行研究，同时结合不同减排措施，明确不同施肥模式油茶园土壤N2O排放动态和强度，阐明不同施肥模式油茶园土壤N2O排放机制及其减排潜力。研究结果表明，集约型油茶园氮肥配施硝化抑制剂双氰胺能够有效降低土壤N2O排放，配施生物质炭能够起到同样的减排效果，且生物质炭与硝化抑制剂施用处理下土壤N2O排放不存在显著差异，证实油茶集约经营中配施生物质炭可能对土壤N2O排放具有一定的减排效果，对提高集约型油茶园土壤保氮减排具有一定的开发潜力。未来研究需探讨油茶园土壤N2O减排条件下的土壤微生物等驱动机制，为红壤区集约经营油茶园土壤N2O减排潜力评估提供科学依据和数据支撑，提高油茶产业经营的生态学效益提供。