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土壤有机质是表征土壤质量的一个重要指标,持续稳定的有机质含量是土壤维持生产能力的基础。土壤有机质的动态演变可以表征土地利用和管理水平。结合地理信息系统,运用地统计方法研究了黑河中游的临泽县绿洲农田20多年来土壤有机质含量的时空变化特征。结果表明:(1)1982年0~20 cm耕层土壤有机质含量平均为12.78±4.38 g/kg,2008年平均为13.76±4.02g/kg;从1982-2008年,有机质含量总体有所上升。(2)两个时期的土壤有机质的实验变异函数值与理论变异函数拟合均较好;克立格插值和不同时期的有机质空间分布图叠加运算表明,由于人为活动的影响,土壤有机质的结构性空间变化程度有所减弱。(3)临泽县土壤有机质含量和变化具有一定的区域性特点:南部的山前平原地区土壤有机质含量较高,呈现上升趋势;中部地势低下的区域土壤有机质相对较高,由于农田面积扩大,有机肥供应不足而下降显著;北部绿洲与戈壁交错带土壤有机质偏低。总体来看,临泽县土壤有机质含量有所上升,但局部地区的有机质发生了下降。为了防止局部区域土壤有机质下降引起土壤退化,应该采取加大有机肥投入和实施秸秆还田等措施。
Soil organic matter is an important indicator of soil quality, and consistent and stable organic matter content is the basis for maintaining soil productivity. The dynamic evolution of soil organic matter can characterize the level of land use and management. In combination with GIS, the temporal and spatial variation characteristics of soil organic matter in the oasis farmland in Linze County in the middle reaches of the Heihe River Basin during the past 20 years were studied using geostatistical methods. The results showed that: (1) The average content of organic matter in 0-20 cm soil layer in 1982 was 12.78 ± 4.38 g / kg and in 2008 was 13.76 ± 4.02 g / kg. From 1982 to 2008, the content of organic matter increased. (2) Both the experimental and theoretical variograms of soil organic matter in two periods are better than others. Kriging interpolation and the spatial distribution of organic matter in different periods show that due to the influence of anthropogenic activities, the structure of soil organic matter The degree of change in sexual space weakened. (3) The soil organic matter content and its change in Linze County have certain regional characteristics: the soil organic matter content in the southern piedmont plain is relatively high, showing an upward trend; the soil organic matter in the lowland area in the central China is relatively high, and due to the expansion of farmland area, The supply of organic fertilizer decreased significantly but the soil organic matter in the northern oasis and Gobi ecotone was low. In general, the content of soil organic matter in Linze County increased, but the organic matter in some areas declined. In order to prevent soil degradation caused by soil organic matter in some areas, measures such as increasing input of organic fertilizer and straw returning should be taken.