压砂年限对土壤质量的影响研究

Research on evolvement of soil quality on gravel mulched field

以宁夏海原县关桥乡罗山村的绵砂压砂地为对象,邻近未压砂地农田为对照,研究压砂1a,3a,5a,7a,10a后土壤机械组成,理化性质及酶活性的变化。结果表明:压砂地与对照相比土壤水分含量高、全盐含量低;随着压砂年限的增加土壤质地粗化、容重明显增加,毛管孔隙度、持水量降低;土壤有机质、全氮、全磷、全钾、硝态氮、速效磷、速效钾均呈下降趋势,过氧化氢酶、脲酶、中性磷酸酶、蔗糖酶的活性也逐年降低。连作3a表现出明显的连作障碍,压砂10a土壤质量状况较差。说明压砂对土壤的影响是双向的。

The gravel- sand mulched of different years of sand- mulching（ CK,1a,3a,5a,7a,10 a,20a,30a）in Luo Shan Village,Haiyuan County,Ningxia Hui Autonomous were studied,and the evolution law of soil mechanical composition,physiochemical and enzyme activity properties of different years of sand- mulching were analyzed. Results indicated that the soil water contents in gravel mulched field were higher than the control,and the total salt content was lower than the control. The soil texture coursed,bulk density significantly increased;soil capillary porosity and the soil water retention were decreased; the contents of soil organic substance,total of nitrogen,phosphorus and potassium,nitric nitrogen,available phosphorus,readily available potassium were all decreased; and the soil enzyme activities（ urease,neutral phosphatase,invertase,catalase） presented a declined trend with the increasing years of continuous cropping. Soil quality showed a minimum value in 10 years of continuous cropping and it shows obvious obstacle of continuous cropping in 3 years.