摘要
用支持向量机分类及回归算法处理我国29个省、市、自治区的土壤中微量元素含量的数据,结果表明:许多微量和主量元素含量以及土壤酸度数据间存在明显的相关关系。能形成碱性氢氧化物的Na,K,Mg,Ca,Sr,Ba等元素的含量相互间呈正相关,并与pH呈正相关;形成难溶性氢氧化物的Al,Fe,Ti,Zr,Ta等元素则与pH呈负相关。这反映了土壤形成和发育过程中湿热气候造成的淋滤作用使碱性氧化物溶解流失,形成酸性土壤的物理化学过程。另方面,我国土壤中Rb,Cs的分布则呈现另外的规律,这可能是由于我国南岭地区和西藏部分地区由富集了亲石元素的重熔花岗岩风化形成的红壤含有富集Rb,Cs 的难风化的云母,使这些酸性的红壤含Rb,Cs特别高。这表明:土壤中微量元素含量既与淋滤作用有关,也与成土母岩的成分和物相有密切关系。鉴于土壤中微量元素含量间以及与酸度间乃至于当地气候间有多种相关关系,当发现土壤中某元素含量和环境效应有相关关系时,需要慎重区分其是否直接因果关系,抑或间接相关关系。
Support vector classification and regression methods have been applied to investigate the data of trace element content in the soil of 29 provinces, autonomous regions and cities of China. It has been found that there exist obvious correlation relationships between the data of the contents of many trace elements and that of major elements or soil acidities. The elements Na, K, Mg, Ca, Sr and Ba, forming basic hydroxides , exhibit positive correlation with the pH of soil; while the elements Al, Fe, Ti, Zr, Ta forming sparsely soluble hydroxides, exhibit negative correlation with the pH of soil. These facts are the results of the leaching action by humid and hot weather environment in the course of the formation and weathering of soil. On the other hand, the data of the contents of Rb and Cs in Chinese soil seem to be the exceptions of the above-mentioned regularities. The red soil of Nanling region and South Tibet is the weathering products of re-melted granite with concentrated lithophile elements, and the Rb and Cs in these red soil are concentrated into muscovite, which is rather stable in weathering process. So that the Rb and Cs contents of these red soil are especially high. This fact indicates that the trace element content in soil is not only dependent on leaching process, but also influenced by the phase relationship of soil-forming rocks. In view of the fact that the contents of many trace elements in soil are correlated with the contents of some other elements or the pH of soil, it should be careful to differentiate the true causal relationship and the indirect correlation if some correlation between certain trace element content and certain environmental effect has been found by data processing.
出处
《计算机与应用化学》
CAS
CSCD
北大核心
2006年第4期299-302,共4页
Computers and Applied Chemistry
基金
国家自然科学基金资助项目(20373040)
上海科委基金资助项目(0452nm019)
关键词
中国土壤
微量元素含量
淋滤作用
岩浆分异作用
trace element content, soil in China, leaching process, magma differentiation
