天津滨海地区土壤剖面盐渍化特征及其影响因素

摘要

Soil salinization is a major environmental risk caused by natural or human activities, and it has an important adverse effect on the industrial and agricultural production activities of mankind. The authors conducted the study of the layout of the 6 representative soil salinization profiles in the coastal areas of Tianjin, and chose 4 profiles as the monitoring sections for the two⁃year monthly sampling and monitoring. Studies show that the soil salinity profiles are of the bottom accumulation types in coastal area, except for BHY6 soil profile which shows the balance of soil profile type with years of farming. The cations are mainly Na+, and the anions are mainly Cl-or Cl- and HCO-3 . From the lower soil profile to the bottom of the shallow groundwater level, the proportions of Na+, Cl- ions in soil pos⁃sess the absolute superiority in the shallow groundwater with significantly higher salinity ( up to saline degree) , and this shows the basic characteristics of coastal solonchak. Climatic factors, salinity and depth of the shallow groundwater and the vegetation in surface soil are important factors affecting soil salinization of coastal areas. The surface soil shows the features of salt accumulation in spring, desalina⁃tion in summer, and slow salt accumulation in autumn and winter. The shallow groundwater mineralization degree is higher, and the shallower the buried depth, the higher the soil salt content. The fruit trees and long cultivated land can reduce soil salt accumulation ef⁃fectively and lower the degree of soil salinization of soil in coastal areas, which is crucial for the protection and improvement of soil.%土壤盐渍化是由自然或人类活动引起的一种环境风险，对工农业生产具有重要影响。本次研究在天津滨海地区布置了6条具有代表性的土壤盐渍化剖面，选取其中4个剖面进行了为期两年的按月采样监测。研究发现，除了BHY6土壤剖面由于长年耕种，表现为平衡型土壤剖面形态之外，其余基本表现为底聚型土壤盐渍化剖面形态；从剖面中下部直到底部浅层地下水位附近，土壤中阳离子以Na＋为主，阴离子以Cl－或Cl－＋HCO－3为主，尤其在浅层地下水矿化度显著偏高（达盐水程度）的地区，土壤中Na＋、Cl－所占比例具有绝对优势，具有滨海盐土的基本发生特征；气候因素、浅层地下水矿化度及埋深、表层土壤植被都是滨海地区土壤盐渍化的重要影响因素。表层土壤表现出春季积盐、夏季脱盐、秋冬季缓慢积盐的特征，浅层地下水矿化度越高、埋深越浅，其土壤剖面含盐量越高；果林地和长期耕种的土地可以降低土壤盐分的活性，有效抑制盐分的累积，降低滨海地区土壤盐渍化程度，保护和改良土壤。