盐渍土改造区土壤养分的时空变异性研究

SPATIO-TEMPORAL VARIABILITY OF SOIL NUTRIENTS IN SALT-AFFECTED SOIL UNDER AMELIORATION

在第二次全国土壤普查的基础上,于2002年10月对研究区域———河北省曲周县的耕地进行了全面的调查和分析,并将GPS、GIS技术应用到耕地质量调查工作中。研究结果表明:随着盐碱地综合治理的深入、外源物投入数量的增加和质量的改进、作物布局的调整,盐渍土改造区土壤养分在时间和空间上发生了很大的变化。在时间上,耕层土壤有机质平均含量从8.4 g kg-1增加到13.89 g kg-1,全氮平均含量达到0.937 g kg-1,速效磷平均含量从5.45 mg kg-1增加到23 mg kg-1,速效钾含量从34~285 mg kg-1之间逐步变化为67~191 mg kg-1之间的高肥力农业土壤;在空间上,土壤养分的分布与养分的地球化学过程、农业产业结构布局及采用的相应措施有密切关系。主要表现在:土壤有机质、全氮及速效磷含量随着农业集约化程度的提高、外源物质投入的增加而相应增加;土壤速效钾含量则由原来的随地球化学过程而变化,转变为随着农业集约化程度的提高而相应变化。

On the basis of the second national soil survey in 1980,all the cultivated lands in Quzhou County,Hebei Province were surveyed and analyzed,and with the aid of GPS and GIS technology in October 2002. The results indicate that with development of the program of comprehensive management of salt-affected soils,improvement in quantity and quality of extraneous input,and readjustment of cropping arrangement,great spatio-temporal variation of soils nutrients in the salt-affected soils of the land amelioration zone. Temporally,soil organic matter and rapidly available P have increased from 8.4 g kg^(-1),and 5.45 (mg kg^(-1)) to 13.89 g kg^(-1) and,23 mg kg^(-1) respectively; total nitrogen up to 0.937 g kg^(-1); and rapidly available K from 34～285 mg kg^(-1) to 67～191 mg kg^(-1). Spatially,the distribution of soil nutrients shows a close relationship with geochemistry process of the nutrients,crops distribution,and cultivation practices. It is represented mainly in that soil organic matter,total nitrogen,and rapidly available P increased in content with the degree of intensification of the farming,and the application rate of extraneous input,and that the content of rapidly available K varies with the intensification of farming instead of originally with the geochemical process.