Estimate of Carbon Sequestration Under Cropland Management in China
Estimate of Carbon Sequestration Under Cropland Management in China
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发表时间：
2008
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通讯作者：
S. Feng
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作者：
S. Feng
【目的】长期大规模常规耕作和秸秆焚烧导致土壤有机质流失严重；这使得农田成为温室气体的排放源。然而，近年来，由于免耕技术的推广和秸秆还田面积的增加，以及施肥、灌溉等广泛的农田管理，农田有机碳不断增加。这将使农田成为一个重要的温室气体汇。分析了不同耕地管理制度下中国土壤有机碳（SOC）的变化，估算了不同耕地管理制度下中国土壤固碳量。这些结果将成为中国农田温室气体清单的基础。【方法】通过回顾相关文献，构建农田管理情景，分析长期试验中不同农田管理制度下土壤有机碳的变化。此外，根据中国不同的耕作制度区域，估算了耕地管理制度下的碳汇数量，并与2006年IPCC《国家温室气体清单指南》中采用的耕地剩余耕地Tier2方法的结果进行了比较。最后，采用元分析方法估算了中国耕地管理制度下的碳固存。【结果】有机肥与无机肥混施是提高土壤有机碳最成功的管理体系，可提高土壤有机碳0.889 tC·ha-1·a-1。秸秆还田，施用有机肥和免耕，分别达到0.597、0.545、0.514 tC·ha-1·a-1。施用无机肥的效果不明显，仅达到0.129 tC·ha-1·a-1。总体而言，这些值显著大于Tier2。结果还表明，不同管理制度、不同地区土壤有机碳的变化也不同。黄淮海河地区、长江中上游地区和西南地区有机碳的增加幅度高于东北地区。在施用无机肥的情况下，东北黑土有机碳含量明显下降。农田管理下土壤有机碳年增长率与土壤有机碳值呈负相关。因此，在不同的管理制度下，可以估算土壤有机碳和固碳潜力的平衡。【结论】无机有机肥配施、秸秆还田、有机肥配免耕均能显著提高土壤有机碳含量。秸秆还田与无机有机肥配合施用固碳效果显著。
【Objective】 Long-time conventional tillage on a large scale and straw burning cause significant losses of soil organic matter (SOM); this makes cropland an emission source of greenhouse gas (GHG). However, in recent years, organic carbon in cropland has been increasing due to the spread of no-tillage techniques, and increas of straw returning area, as well as extensively cropland management such as fertilization and irrigation. This can turn the cropland into an important sink of GHG. This paper analyzed the change of soil organic carbon (SOC) under different cropland management regimes, estimated carbon sequestration under cropland management in China. The results will be the base for a GHG inventory of Chinese croplands. 【Method】Through reviewing relevant references and constructing cropland management scenarios, the change of SOC under different cropland management regimes in long-term experiments were analyzed. In addition, according to farming system regions in China, the quantities of carbon sink under cropland management regimes were estimated and compared with the results of Tier2 approach of cropland remaining cropland in 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Finally, Meta-Analysis was used toestimate carbon sequestration under cropland management regimes in China. 【Result】The most successful management system for increasing SOC was using inorganic and organic fertilizers together, which could increase SOC 0.889 tC·ha-1·a-1. Next came straw returning, using organic fertilizer and no-tillage, respectively achieving 0.597, 0.545, 0.514 tC·ha-1·a-1. The effect of using inorganic fertilizer was not evident, only reaching 0.129 tC·ha-1·a-1. On the whole, these values were significantly larger than those of Tier2. Results also showed the change of SOC varied with different management systems and different areas. The increase of SOC in the Yellow-Huaihe-Haihe Rivers region, the upper and middle reaches of Yangtze River region and the southwest region was higher than that in the northeast region. There was even a decrease in SOC in Black Soil organic in the Northeast under application of inorganic fertilizer regimes. There was a negative relation between the annual growth rate of SOC and the value under cropland management. So the balance of SOC and carbon sequestration potentials could be estimated under different management systems. 【Conclusion】 The cropland management techniques of using inorganic and organic fertilizer together, straw returning, using organic fertilizer and no-tillage could all increase SOC significantly. Carbon sequestrations of straw returning and using inorganic and organic fertilizer together were great.