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利用1980年全国第二次土壤普查的102个土壤剖面(0~100 cm)和147个表层样(0~20 cm),以及2009年采集的39个土壤剖面和241个表层土样属性数据,分别计算灌区表层和剖面土壤有机碳密度,通过对比分析,研究了宁夏引黄灌区近30年来土壤有机碳储量的变化特征。结果表明:1980—2009年,宁夏引黄灌区表层(0~20 cm)土壤有机碳密度由16.57 Mg C·hm-2增至21.44 Mg C·hm-2,平均年增幅为0.98%(P<0.01);剖面(0~100 cm)土壤有机碳密度平均由55.70 Mg C·hm-2增至58.49 Mg C·hm-2,平均年增幅为0.17%(P>0.05);土壤类型是影响灌区土壤有机碳储量的主导性因素;灌区土壤有机碳密度与灌溉时间之间有较强的相关性(P<0.01),灌溉耕作时间越长,土壤有机碳密度越高;单位面积化肥施用量、单位面积作物产量及作物种植类型对灌区土壤有机碳变化产生了重要影响;气温和降水对土壤有机碳变化影响不明显。引黄灌溉耕作对提高灌区土壤有机碳储量和降低温室气体排放具有积极的作用。
Based on the data of 102 soil profiles (0 ~ 100 cm) and 147 surface samples (0 ~ 20 cm) from the 1980 second national soil survey and 39 soil profiles and 241 surface soil samples collected in 2009, The density of soil organic carbon in the surface and the section of the irrigated area was calculated respectively. Through comparative analysis, the change characteristics of soil organic carbon storage in the irrigated area of Ningxia Yellow River were studied in the past 30 years. The results showed that from 1980 to 2009, the soil organic carbon density of surface soil (0-20 cm) increased from 16.57 Mg C · hm-2 to 21.44 Mg C · hm-2 in the Yellow River Irrigation Area, with an average annual increase of 0.98% (P < 0.01). Soil organic carbon density increased from 55.70 Mg C · hm-2 to 58.49 Mg C · hm-2 on average (0 ~ 100 cm), with an average annual increase of 0.17% (P> 0.05) There was a strong correlation between soil organic carbon density and irrigation time in irrigated area (P <0.01). The longer the irrigated tillage time was, the higher the organic carbon density was. The amount of chemical fertilizer per unit area, The yield per unit area of crop and the type of crop planting had an important effect on the change of soil organic carbon in irrigated area. The effect of temperature and precipitation on the change of soil organic carbon was insignificant. Irrigation practices in the Yellow River have a positive effect on increasing soil organic carbon storage and reducing greenhouse gas emissions in irrigated areas.