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利用农业生态系统生物地球化学模型(DNDC),选择6个典型的种植模式点,在特定的土壤和气候条件下运行模型,考察在其它投入条件不变的情况下,改变田间管理措施(秸秆还田、增施有机肥、改变化肥施用等)对土壤有机碳(SOC)含量影响的长期效应。研究结果表明,在众多的管理措施中,增加秸秆还田比例的固碳效应在众多的农田管理措施中体现最突出,以基本管理措施20年后有机碳含量为对照,当秸秆还田率增加到80%时,齐齐哈尔、平凉和芷江地区增加的SOC含量都在C 3 000 kg/hm2以上,北京郊区、江宁和盐亭地区每公顷则可以增加C10 000 kg以上。化肥增加SOC含量是通过增加作物还田残茬来实现的,与基本措施相比,除了华北和华东地区增施化肥使SOC含量显著增加外,其它地区均不明显。化肥施用量为本底值的50%配合秸秆还田率50%和化肥施用量为本底值的50%增施有机肥C 1 000 kg/hm2的两项措施,在各个地区都表现出比基本管理措施能存储更多的碳素,因此,在我国现在措施下,减少化肥的同时增加秸秆还田比例和增施有机肥是既增加土壤有机碳含量又减少化肥污染的“双赢”措施。
Based on DNDC, six typical planting patterns were selected to run the model under specific soil and climatic conditions. The changes of field management practices under the condition of other inputs Field, increasing organic fertilizer, changing fertilizer application, etc.) on soil organic carbon (SOC) content. The results showed that in many management measures, the carbon sequestration effect of increasing the proportion of returning straw to straw was the most prominent in many farmland management measures. Compared with the organic carbon content after 20 years of basic management measures, when the straw returning rate increased At 80%, the SOC content in Qiqihar, Pingliang and Zhijiang areas will be above C 3 000 kg / hm 2, while C 10 000 kg / ha can be increased per hectare in Beijing suburbs, Jiangning and Yanting. The increase of SOC content by fertilizers was achieved by increasing the stubble of crop returning to the field. Compared with the basic measures, except for the fertilization in North China and East China, the content of SOC increased significantly, while the other regions were not obvious. Fertilizer application rate of 50% of the background value with 50% of the straw return rate and fertilizer application rate of 50% of the background value of the two organic fertilizer C 1 000 kg / hm2, in all regions showed a ratio of Therefore, under the present measures of our country, reducing the proportion of fertilizers while increasing the proportion of straw returning and increasing organic fertilizers is a “win-win” solution that not only increases the content of soil organic carbon but also reduces the pollution of fertilizers. Measures.