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在ArcGlS8.1软件系统平台上,通过分析四川郫县土壤耕层1981年93个样点和2002年46个样点的有机质含量,研究了该县有机质的时空变化特征。结果表明,郫县耕层土壤有机质平均含量从1981年的26.4gkg-1增加到2002年的28.2gkg-1。其区域变化差异为:东部略微下降,中部与西部增加。近21年来水稻土有机质平均含量仅少量增加,而黄壤则增幅明显。距成都市区的远近和推广秸秆还田程度是引起耕层土壤有机质含量时空变异的主要原因。
On the ArcGlS8.1 software system platform, by analyzing the organic matter content of 93 samples in 1981 and 46 samples in 2002 in Pixian County, the spatial and temporal characteristics of organic matter in the county were studied. The results showed that the average content of organic matter in the topsoil of Juxian County increased from 26.4gkg-1 in 1981 to 28.2gkg-1 in 2002. The regional differences are as follows: a slight decrease in the eastern part and an increase in the central part and the western part. In recent 21 years, the average content of organic matter in paddy soil increased only slightly, while the yellow soil increased significantly. The distance from Chengdu urban area and the promotion of straw returning to soil are the main reasons that cause the spatio-temporal variations of soil organic matter in topsoil.