土壤微量元素测试及其应用

Soil testing for trace elements and its application.

土壤微量元素测试在其发展历史过程中,不断改进技术,逐渐深入地揭示土壤供给微量元素的能力,对指导施肥和保护生态环境起着积极的作用。现代测试手段发展到广泛采用原子吸收光谱(AA)和电感耦合等离子体发射光谱(ICP),但比色法(光度法)和极谱法不仅设备比较简便,而且新的显色剂、催化系统等方面的研究进展,使其对某些元素的测定灵敏度和准确度超过AA和ICP,从而在微量元素测试技术中仍占据一定地位。土壤溶液抽取技术虽然有所改进,但有效态微量元素仍然主要是选用适当提取剂来提取测定。临界值和分级标准的确定是应用测定值的桥梁。作者曾采用全幅分级标准分级制图,确定缺素面积和需肥区域,再根据土壤含量水平和增产幅度之间的函数关系预测增产效果和投入的经济效益。

In the development process of soil testing for trace elements, the test techniques are being improved, abilites of soil in applying available trace elements are revealed more thoro ughly, and positive roles of soil testing in fertilization and protection of ecological en vironment are played more obviously.Recently,the test means adopted widely are AA and ICP, but photometry and polarography still occupy a certain position in soil test of trace elements,because of their handy equipments and the improvement of their sensitivity and accuracy. Available trace elements in soils are mainly extracted by selected extractants, techniques for directly extracting soil solution are improved, and hence, it may be possible to easily determine the level of trace elements in soil solution. Critical values or criteria may be evaluated by various methods and act as a bridge in the application of test values. The author adopts the criteria to grade test values of soil available trace elements in Taching and make maps, so as to ascertain the deficiency area and fertilizer-demand regions.Then,effects of fertilization and economic benefit may be forecasted by means of functional relation between level of available trace element and yield increase percentage.