耕作层土壤是农业生产的物质基础,是耕地资源的核心,剥离利用对保障耕地数量和质量动态平衡具有重要意义.该研究在江苏省内收集了来自20世纪80年代的201个代表性土壤剖面及其不同层次有机质、容重、pH值、全氮、全磷、速效钾和土层厚度等属性数据,通过主成分分析确定江苏省耕地肥力差异主控因子,在此基础上运用聚类分析得出江苏省耕地肥力性质差异分区,最后采用显著性检验方法,得出了全省不同分区下耕地耕作层土壤剥离深度.通过研究发现:1)对于所选取的指标体系来看,影响全省耕地肥力性质差异的因素主要有pH值、全磷、全氮含量和容重.2)江苏省耕地土壤亚耕层/犁底层与表耕层肥力相似、性状略差,应考虑剥离利用,而心土层与表耕层、亚耕层/犁底层差异较大,不具有所需的质量,不宜剥离利用.3)全省耕作层土壤剥离深度可分为6个区,分区结果与农业综合区划相类似.4)耕作层土壤剥离深度应区分水田、旱地、菜地,并结合全省不同地区的耕地保护压力、耕地(农用地)年转用量、复垦开发补充耕地面积情况等,实施差别化的管理.可为江苏省耕作层剥离工作提供参考.%Cultivated soil is the material base of agricultural production and the core of arable land resources.Stripping utilization is of great significance to guarantee the dynamic balance of quantity and quality of arable land.The data of 201 representative soil profiles and organic matter,bulk density,pH value,total nitrogen,total phosphorus,available potassium and soil thickness were collected from Jiangsu Province in the 1980s.Principal component analysis was adopted to determine the dominant factor of cultivated land fertility difference in Jiangsu Province.And based on the cluster analysis,the difference of cultivated land fertility in Jiangsu Province was then partitioned.Finally,the significance of soil fertility was analyzed by using the method of significance test,and the soil stripping depth of cultivated land under different subarea was obtained.The results showed that:1) For the selected index system,the factors affecting the difference of fertility of cultivated land in the province were pH value,total phosphorus,total nitrogen content and bulk density.It could be seen that within the scope of Jiangsu Province,the 4 types of soil properties changes could better represent the province's soil properties.The clustering results of different methods were different,but they all showed the trend of gathering in space,which meant that the physical and chemical properties of soils in the similar areas were also closer,which was consistent with previous studies.2) Through the clustering analysis of the main components of farmland fertility,the soil stripping depth of cultivated land could be divided into 6 zones,each of which contained the different number of regions.It could be seen from the results of different clustering methods that the geographical location in the same classification was also close to each other,and the areas with similar location also had similar soil background and fertility properties.The accuracy of the results was mainly influenced by clustering methods.If selecting the different classification results as a reference,the evaluations of the conclusions were consistent.It could be seen for the soil fertility in Jiangsu Province,the regional differences were objective,and according to the Ttest results,the significant difference could be seen.3) For the most areas of the province,the surface layer and sub-plow layer / plow bottom layer had similar traits and fertility,which could be stripped at the same time to improve the utilization efficiency of arable land resources,and reduce the waste and loss of high-quality farmland to a maximum degree.While the sub-plow layer / plow bottom had a larger difference with subsoil layer,which did not have the required quality,and hence should not be stripped.4) In view of the soil fertility of the cultivated land in this province,the sub-plow layer / plow bottom layer was close to the topsoil layer and obviously higher than that of the subsoil layer.However,the soil physical structure of the sub-plow layer / plow bottom layer was too tight,and the bulk density was relatively large.So it is proposed to distinguish paddy field,dry land and vegetable land.According to the pressure of cultivated land protection in different areas of this province,the annual conversion amount of cultivated land (agricultural land),the area of supplementary cropland,different stripping depth should be adopted.
展开▼
