ANALYTICAL STUDIES ON THE SOIL RELATED CHARACTERISTICS AT KOCHI-PREFECTURE

主要研究结果如下：(1)农业发展的历史与现状分析：(1)运用主成分分析和聚类分析，得出新的城乡分工中的六种农业结构类型和旧分工中的八种农业结构类型。(2)地质和土壤特征在新区划的农业类型中得到了很好的体现。(3)高知县中部地区绿地重金属对农业生产有不良影响。(4)需要特别注意创造含有混杂岩的农田。(B)零电点(ZPC)分析：使用来自四个地区的11个土壤样本进行ZPC的评估。ZPC和Sigma_p的大小被认为是与其他理化特性相关的良好指标。(1)即使p…被认为是与其他理化特性相关的良好指标更多的残留电荷粘土是土壤的主要电荷来源，随着可交换铝量的增加，Sigma_p的大小增加。此外，有机质对降低ZPC和增加Sigma_p的贡献在有丰富的永久电荷矿物存在时变得不那么显著。(3)ZPC和Sigma_p的值是相互调节的，(4)施肥，特别是石灰改良剂，(C)重金属分布：详细研究了Kagami和Yasu-cho土壤中重金属的数量和形态，新的发现如下：(1)对于Kagami土壤，(1)包括铜在内的农用化学品的使用等人为原因可能会增加土壤中的全铜含量；(2)分级研究表明，经人为修正和来源于母质的土壤中的铜的形态存在差异。对于Yasu土壤，2C和3C土层受铜矿和/或铁矿本身的影响较大。(3)在温室条件下，灌溉水不可避免地进一步增加土壤中的铜含量，可能通过在表层积累铜而对作物生产造成损害。较少

The main results of the analysis are as follows.(a) Analysis About History and Current Situation of Farming: (1)Using the principal analysis and cluster analysis, we got six types of agricultural structure in the new division of cities, towns and villages and eight types of agricultural structure in old division. (2) Geological and soil feature are reflected in the agricultural types of the new division well. (3)Bad effect of heavy metal originated from greenstons on farming is observed in the central area at Kochi-prefecture. (4)Special attention is needed to create farming land which contains melange rocks.(b) Analysis of Zero Point of Charge (ZPC):Evaluation of ZPC was done using soil samples of eleven pedons from four regions,namely,Ohgata-cho,Taisho-cho,Yasu-cho,and Kagami-cho.ZPC and the magnitude of sigma_p were considered as good measures in relation to other phisico-chemical characteristics.New findings using the samples examined here are summarized as follows:(1)Even if the p … More ermanent charge clays are dominant as a charge source of soils,the magnitude of sigma_p increased with the amount of exchangeable aluminum,(2) furthermore,the contribution of the organic matter to lower the ZPC and to increase in the magnitude of sigma_p, which is normally recognized for strongly weathered soils,becomes less significant in the presence of permanent charge minerals in abundance.(3)the values of ZPC and sigma_p are regulative with each other,and (4) fertilization,especially lime amendment,makes ZPC value higher and sigma_p value larger.(c) Heavy Metal Distribution:The amount and form of heavy metals were examined in detail for the soils at Kagami and Yasu-cho,and the new findings are as follows.For kagami soils,(1)Anthropogenic cause,such as an application of agrochemicals including Cu,may increase the total Cu content,and (2)Fractionation study showed the difference in the form of Cu between the ones anthropogenically amended and originated from the parent materials. For Yasu soils,the 2C and 3C horizonds are strongly affected by the Cu and/or Fe mine itself.and (3) further increase in Cu content inevitably introduced by the irrigation water in situ may cause a damage to the crop production gradually through accumulation of Cu at the surface layer in the green house condition. Less