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引 言 土壤分类单元间亲疏关系或从属关系的数值评定,即土壤的数值分类,是以土壤分类指标(主要是属性指标)、的数值化为基础,通过对各单个土体(pedon)调查资料和数据的获得、整理和运算,形成一种以数值为依据的土壤分类体制。土壤的数值分类系统可以独立应用,便于用电子计算机贮存信息、制图和鉴定待测土壤;但在目前的发展水平上更多地是用数值分类方法来论证或评定现有的直观土壤分类系统,把主观比土的结果置于数值运算的基础上进行检验。从本世纪六十年代起,国外就有一些土壤学者开展土壤数值分类的研究工作;1978年中国土壤学会举行全国土壤分类会议以来,这种数值方法在我国也逐渐有了可喜的发展。本文是同时运用以主分量分析为主、结合聚类和回归分析的几种多元分析方法,探讨南京附近低山丘陵区林业用地土壤分类和生产力评价问题。这项工作的目的,一方面是探索综合应用这些方法的可行性及其实际效果,另一方面是把现有的江苏南部低山丘陵区土壤分类方案,置于这些数值方法综合应用的基础上作一次检验,以进一步论证其合理性。 这里所说的现有分类方案,是指我们在1978年拟订的一个,具有7个土类24个土型,主要是根据母质类型和土壤属性,适当参照我国现行土壤分类规范而制定(表1),并且作过一些土壤生产
INTRODUCTION The numerical evaluation of the relationship between the ancestry and the affinities of soil taxa, that is, the numerical classification of soils, is based on the numericalization of the soil taxonomic index (mainly the attribute index). Based on the survey data of individual pedon The data is obtained, collated and calculated to form a soil-based numerical classification system. Soil numerical classification systems can be used independently to facilitate the computerized storage of information, mapping and identification of soil under test. At present, however, numerical classification is more often used to justify or assess existing visual soil classification systems, The result of subjective comparison of soil is tested on the basis of numerical calculation. Since the 1960s, some soil scientists abroad have carried out research work on soil numerical classification. Since 1978, when the China Soil Society held a national soil classification conference, this numerical method has gradually enjoyed a good development in our country. In this paper, we use multiple multivariate analysis, which is mainly based on principal component analysis and cluster analysis and regression analysis, to evaluate the soil classification and productivity evaluation of forestry land in the hilly area of Nanjing. The purpose of this work is to explore the feasibility and practical effects of the comprehensive application of these methods on the one hand and to put the existing soil classification schemes in the hilly region of southern Jiangsu on the basis of comprehensive application of these numerical methods Make a test to further demonstrate its rationality. The existing classification scheme referred to here refers to one of the 24 soil types of 7 soils we formulated in 1978, which is mainly based on the parent material types and soil properties, with reference to the current soil classification code of our country (Table 1 ), And made some soil production