华中地区旱地农田管理措施对土壤有机碳及固碳潜力的影响

发布时间：2018-03-26 15:24

本文选题：农田管理措施　切入点：Century模拟　出处：《华中农业大学》2017年硕士论文

【摘要】：由大量温室气体排放导致的气候变化是全球性的环境问题,增加土壤碳汇是缓解气候变暖的有效途径。土壤有机碳库是土壤碳库的重要组成部分,而农田土壤有机碳库在全球土壤有机碳库占比巨大。在不同的管理措施下,农田土壤有机碳含量存在较大差异。明确不同农田管理措施下土壤有机碳的变化趋势特征,对于优化区域农田管理措施,提高作物生产力和农田土壤肥力以及缓解气候变化具有现实意义。本文以华中地区旱地轮作长期定位试验站点的监测数据为基础,用实测作物产量和土壤有机碳数据对Century模型进行校验、验证与评价。在确定该模型用于模拟华中地区旱地轮作土壤有机碳变化适宜性的基础上,分析单一及组合农田管理措施对土壤有机碳的变化和土壤固碳潜力的影响。探讨在当前及政策秸秆还田率下土壤有机碳的变化趋势,以及在保持有机肥施用量不变条件下,减少氮肥施用的潜力。论文获得的主要研究结果如下。(1)农田土壤有机碳在各管理情景下变化趋势差异显著。其中,免耕较传统耕作能够减缓3.95%的土壤有机碳下降幅度;施肥管理对土壤有机碳和土壤固碳潜力的影响与施氮量和施肥结构密切相关;秸秆还田能有效提高土壤有机碳和土壤固碳潜力,全部还田时土壤有机碳含量增加了1932.77 g/m~2,且玉米秸秆优于小麦秸秆;不同农田管理措施间存在交互作用。(2)在保持当前秸秆还田率固定不变或采取国家政策规划秸秆还田率时,维持当前常规氮肥施用方案能够保障土壤有机碳的相对稳定及持续积累,具有706.51-1003.65 g/m~2的土壤固碳潜力,作物产量也维持相对稳定。(3)在有机肥施用强度不变条件下,华中地区旱地轮作减少30%(9.81g/m~2)氮肥施用量,可以维持作物产量的相对稳定,并持续提高土壤有机碳含量。
[Abstract]:Climate change caused by a large amount of greenhouse gas emissions is a global environmental problem. Increasing soil carbon sinks is an effective way to mitigate global warming. Soil organic carbon pool is an important part of soil carbon pool. However, the soil organic carbon pool accounts for a large proportion of the global soil organic carbon pool. Under different management measures, there are great differences in soil organic carbon content. This paper is of practical significance for optimizing regional farmland management measures, improving crop productivity and soil fertility, and mitigating climate change. The Century model was verified and evaluated with the measured crop yield and soil organic carbon data. The model was used to simulate the suitability of soil organic carbon variation in dryland rotation in central China. The effects of single and combined farmland management measures on the change of soil organic carbon and the potential of soil carbon sequestration were analyzed. The change trend of soil organic carbon under the current and policy straw return rate and the condition of keeping the application rate of organic fertilizer unchanged were discussed. The main results obtained in this paper are as follows: (1) the change trend of soil organic carbon in farmland under different management scenarios is significantly different, among which, no-tillage can slow down the decline of soil organic carbon by 3.95% compared with traditional tillage. The effects of fertilization management on soil organic carbon and soil carbon sequestration potential were closely related to nitrogen application amount and fertilizer structure, and straw returning to the field could effectively improve soil organic carbon and soil carbon sequestration potential. The soil organic carbon content increased by 1932.77 g / m ~ (2) and the corn straw was superior to the wheat straw when the soil organic carbon content was increased by 1932.77 g / m ~ (2), and there was interaction between different farmland management measures, while keeping the current straw return rate unchanged or adopting the national policy to plan the straw return rate, Maintaining the current routine nitrogen application scheme can ensure the relative stability and sustainable accumulation of soil organic carbon, and has the potential of carbon sequestration of 706.51-1003.65 g/m~2, and the crop yield is also relatively stable under the condition of constant application intensity of organic fertilizer. Rotation of dry land in central China reduced the amount of nitrogen fertilizer by 30 ~ 9.81g / m ~ (-2), which could maintain the relative stability of crop yield and increase soil organic carbon content continuously.
【学位授予单位】：华中农业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S153.6

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