沈抚石油污灌区土壤有机质空间分布

Spatial distribution of soil organic matter in Shen-Fu oil-sewage irrigation area

利用CIS技术对沈抚灌区土壤有机质的空间分布规律进行了研究，并分析了其影响因素。结果表明：土壤有机质含量沿灌渠上游至下游逐渐减少，且在垂直灌渠方向上，距灌渠越远，含量越低，表层土壤有机质含量显著高于亚表层（平均值为亚表层的1．7倍）；沈抚灌区土壤有机质空间分布受土地利用方式、污灌形式和污灌年限影响；水田有机质变异系数大于旱田，随灌渠水流的流向，土壤中有机质含量逐渐减少，在下游地区存在异常区；土壤有机质含量随污灌年限的增长而上升，污灌36—50年的水田表层和亚表层有机质含量是其它年限的1．71—2．36和2．51～2．87倍，旱田表层有机质含量在污灌16年后变化不大，保持在3．2％～3．6％。

The spatial distribution of soil organic matter （SOM） and the affecting factors were studied based on the GIS technology in typical oil-sewage irrigation area of Shen-Fu, China. The results were followed the SOM content decreased from upper to lower reaches along Shen-Fu wastewater irrigation ditch and there was a negative correlation between the SOM content and the distance to the ditch. The mean content of SOM in surface layer was 1.7 fold more than that of subsurface layer in Shen-Fu irrigation area. The spatial distribution of the SOM content was af- fected significantly by land use type, sewage irrigation style, and irrigation duration. The coefficient of variance for SOM in paddy field was bigger than that in glebe. Along wastewater current in the ditch, the SOM content decrease gradually, but in lower reaches the SOM content was higher. The SOM content increased with sewage irrigation duration prolonged. Compared to the short duration in sewage irrigation area, the SOM contents of surface layer and subsurface layer in paddy irrigated 36-50 years increased by 71%-136% and 151%-187% respectively, and that of surface layer in glebe land after being irrigated for 16 years was 3.2%-3.6%.