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通过采样分析,结合20世纪80年代全国第二次土壤普查土壤有机碳数据,对庄浪县农田耕层(0~20 cm)土壤近30年有机碳变化及影响因素进行研究.结果表明:①全国第二次土壤普查时土壤平均有机碳含量为6.80 g·kg-1,2011年为8.90g·kg-1.近30年有机碳含量增加了30.9%,表现为碳汇效应.有机碳含量增加的农田面积约占庄浪县耕地总面积的90%.②在现有管理措施和农田投入下,黄绵土有机碳的稳定水平约为11.0 g·kg-1.有机碳积累量呈现出离稳定值越远变化越大、离稳定值越近变化越小的规律.③近30年土壤有机碳含量变化受海拔高度、初始有机碳含量和土壤类型等因素的显著影响,其中海拔高度对有机碳变化的影响程度最大,初始有机碳含量、土壤类型、产量及有机肥用量对土壤有机碳变化的影响次之,坡向对有机碳变化的影响最小.
Based on the sampling analysis and the soil organic carbon data of the second national soil survey conducted in the 1980s, the changes of organic carbon in the topsoil (0 ~ 20 cm) of farmland in Zhuanglang County and its influencing factors were studied. The results showed that: ① In the second national soil survey, the average soil organic carbon content was 6.80 g · kg-1 and 8.90 g · kg-1 in 2011. The organic carbon content increased by 30.9% in the past 30 years, showing the carbon sink effect. The increase of farmland area accounts for about 90% of the total cultivated land in Zhuanglang County.②The stability of organic carbon in loessial soil is about 11.0 g · kg-1 under the current management measures and farmland inputs, and the accumulation of organic carbon shows a tendency of being stable The change of soil organic carbon content in the past 30 years was significantly affected by factors such as altitude, initial organic carbon content and soil type, among which the effects of altitude on organic carbon The effect of change is the greatest. The effect of initial organic carbon content, soil type, yield and organic manure on the change of soil organic carbon is the second, and slope direction has the least effect on the change of organic carbon.