柴达木盆地细土平原带土壤盐分及其组成的盐渍特征

Saline Characteristics of Soil Salt and its Components in Qaidam Basin

柴达木盆地在青海省具有重要的生态地位。主要分析了青海省柴达木盆地土壤盐分及其组成的盐渍特征,为盐碱地的合理开发利用提供依据。以柴达木盆地不同程度盐渍化土壤的221个样点数据为基础,通过传统的Fisher统计分析方法和相关分析法研究主要盐分指标的变异性和相关性,并依据全国第二次土壤普查时制定的"青海省海西州农业土壤盐化程度分级标准",将柴达木盆地的土壤盐化程度分为5级。土壤盐分及其组成的变异系数范围在2.8%~597.7%,Cl^-、K^+、Na^+、全盐、Ca^2+和SO42-的变异系数较大,均高于100%,pH值变异系数最低,仅为2.8%,阳离子代换量(CEC)、有机质和HCO-3属于中等程度变异,变异系数在10%~100%之间。全盐量与K^+、Ca^2+、Na^+、Mg2+、CO32-、SO42-和Cl^-之间呈极显著正相关(P<0.01),与有机质、阳离子代换量和HCO-3之间呈显著负相关。随着盐化程度的增加,全盐、K^+、Ca^2+、Na^+、Mg2+、SO42-和Cl^-含量也逐步提高,但CEC、有机质和HCO-3则越来越低。柴达木盆地细土平原带盐渍化过程主要表现为Na^+和Cl^-逐渐占据主导地位的过程,最终形成氯化物盐土。土壤有机质的提升有利于减轻土壤盐渍化,农业生产中可通过增施有机肥改良盐渍化土壤。

Qaidam Basin often plays an important ecological role in Qinghai Province. So, in order to provide the basis for the rational development and utilization of saline-alkali land in Qaidam Basin, this investigation is carried out to study the saline characteristics of soil salt and its composition. The combination of Fisher statistical analysis methods and correlation analysis is used to analyze the data from 221 soil sampling sites. According to the soil salinity classification standard of Haixi Zhou, Qinghai Province during the 2 nd national soil survey, the soil salinity is classified into Grade 5 for different soil salinization type and major soil salt components. The results show that the coefficient of variation of soil salt and its components ranged from 2.8% to 597.7%. The coefficient of variation of the Cl^-, K^+, Na^+, total salt, Ca^2+and SO42- were high variation and the values were all over 100%. The coefficient of variation of pH value was lowest, the value was 2.8%. The coefficient of variation of cation exchange capacity, organic matter and HCO-3was moderate variation, the values ranged from 10% to 100%.There was a significant positive correlation between total salt and K^+,Ca^2+,Na^+,Mg2+,CO32-,SO42-,Cl^-(P<0.01),respectively. There was a significant negative correlation between total salt and organic matter, cation exchange capacity, HCO-3, respectively. Then, the contents of total salt, K^+, Ca^2+, Na^+, Mg2+, SO42-and Cl^-were enhanced, but the contents of cation exchange capacity, organic matter and HCO-3were reduced with the increase in soil salinization. Na^+ and Cl^- were the dominant process during the salinization process in fine soil plain belt of Qaidam Basin,eventually becoming the chloride salt. Increasing soil organic matter is beneficial to the reduction of soil salinization,so it can be used to improve saline-alkali land by applying the organic manures in the agricultural production.