弱碱性土有效硫测定影响因素的探讨  

A Discussion on the Effect Factors of Available Sulphur Determination in Weak Alkaline Soils

作　　者：刘婷琳[1] 马名扬[1] 胡耀国[1] 彭四清[1] 

机构地区：[1]广东省生态环境与土壤研究所,广东广州510650

出　　处：《岩矿测试》2011年第2期182-185,共4页Rock and Mineral Analysis

基　　金：国家自然科学基金资助(40771129);广东省科技攻关重点项目资助(2008A0302004;2008A020100010);广东省科学院分析测试基金资助(sf200901)

摘　　要：准确测定土壤中有效硫的含量,对土壤硫元素是否缺乏的判定及合理施用硫肥具有重要的意义。测定碱性土中有效硫的含量可以采用pH=8.5的碳酸氢钠浸提后测定浸提液中硫的含量。文章采用碳酸氢钠法浸提弱碱性土中的有效硫,紫外-可见分光光度法测定,针对影响弱碱性土中有效硫测定过程中浸提液的氧化脱色、比浊液的酸度条件等影响因素进行了详细探讨。结果表明,在20～25℃提取条件下有效硫测定值基本一致,而30℃提取条件下样品测定值有偏高的趋势;比浊液的酸度选择盐酸的加入量大于1.5 mL,测定精度高,线性好。方法回收率为96.6%～104.6%;对于土壤中6～25 mg/kg有效硫的测定,标准偏差为0.110～0.271 mg/kg,变异系数均<5%。建立的方法快速、简便、准确,重复性和再现性较好,适用于各种类型弱碱性土壤中有效硫的分析检测工作。The high precision data of S concentration in top soil is an important proxy to estimate the sulphur loss in top soil.A discussion is presented in this paper on the effect factors of available sulphur determination in weak alkaline soil with pH=8.5 sodium bicarbonate extractants.A further study was made on the oxidizing discoloring of extractive solution and the acidity of turbidimetry solution during the determination process.The results indicated the reliable data were obtained in the temperature range of 20 ℃ to 24 ℃,but the analytical data were higer if the temperature was higher than 30 ℃.The recovery of this method was 96.6%-104.6%,the standard deviation was 0.110-0.271 mg/kg,and a relative standard deviation of 5% if the S concentration is between 6-25 mg/kg in top soil.The method has the advantage of being fast,simple,accurate and highly reproducible,which could apply to determine S concentration for various kinds of weak alkaline soils.

关 键 词：有效硫 弱碱性土 影响因素 

分 类 号：S151.93[农业科学—土壤学] O613.51[农业科学—农业基础科学]