关键词: 土壤有机质, 水田, 时空变异, 成都平原

Abstract: [Objective] Knowing the tempo-spatial variations of soil organic matter(SOM) is very important to improve the utilization efficiency of cultivated land and for agricultural sustainable development. [Method] Based on the second soil census in 1982, 202 paddy soil samples were collected using GPS technique in Pengzhou. Tempo-spatial variations of SOM in the paddy fields from 1982 to 2007 were evaluated using geostatistics and geographic information system. [Results] SOM contents were obviously increased in paddy fields. The average SOM content was increased from 25.65 g/kg in 1982 to 33.04 g/kg in 2007. Most of SOM content grade was improved from grade Ⅲ to Ⅱ. There were significant changes in the spatial distribution of SOM between two years. The areas of high SOM content were shifted from southeast to central and the areas of low values were shifted from northeast to southwest. SOM was increased in 94.2% of the investigated paddy fields. Therefore, paddy soil was better for carbon fixation. [Conclusion] Distribution patterns in SOM of paddy fields in Pengzhou varied strongly with time. This result may be helpful to guide paddy field fertilization and to formulate the relevant policies.

Key words: soil organic matter, paddy field, tempo-spatial variation, Chengdu plain