近代及现代黄河三角洲不同尺度地貌单元土壤盐渍化特征浅析

近、现代黄河三角洲近50%的土地为不同程度的盐渍化土。在土壤盐渍化过程中,地貌因素至观重要。地形的高低起伏,影响地面、地下径流的运动,土壤中的水分和盐分也就随之重新分配和积累。研究的目的是分析不同尺度下地貌单元之间土壤盐渍化特征差异及原因。为此,利用2002年5月23日到29日对近、现代黄河三角洲野外考察、GPS定点和土壤采样分析所得数据,对6个表征土壤盐渍化特征的参数(土壤的全盐量、pH值、有机质、Cl-/SO42-、HCO3-/(Cl- SO42-)、(K Na )/(Ca2 Mg2 ))进行统计分析,并进行多个独立样本的非参数检验(Kruskal-WallisTest和MedianTest),检验6个参数在同一尺度不同地貌单元之间是否有明显的差异,结果表明:(1)近、现代黄河三角洲土壤盐渍化程度严重,整体属于滨海氯化物型盐渍土类型,有机质相对缺乏,土壤偏碱性。随土层深度增加(0cm￣10cm、10cm￣30cm、30cm￣60cm),盐渍化程度逐渐减轻;(2)同一尺度下不同地貌单元之间土壤盐渍化特征存在差异。一般地,随尺度变小(从一级到四级地貌单元),土壤盐渍化特征差异越来越明显,存在差异的参数也逐渐增加。一级地貌单元只有pH值明显不同,从二级地貌单元到四级地貌单元,3个土层土壤的全盐量随不同的地貌单元而有明显的差别,且随着土层深度的增加,HCO3-/(Cl- SO42-)和(K Na )/(Ca2 Mg2 )也变得明显不同。这也说明不同地貌单元下盐分组成及离子比例、积盐、脱盐过程存在差异,且随土层深度增加差异越大。

Elementary Analysis on Characteristics of Soil Salinization of Geomorphology Units with Different Scales in the Neoteric and Modern Yellow River Delta

About 50% of the soils in the Neoteric and Modern Yellow River Delta are affected by salinity. The Geomorphology is a key factor for soil salinization. The hypsography affects the movement of surface and underground runoff, along with it water and salt content in soils are redistributed and accumulated. The objective of this research is to analyze the diversities of characteristics of soil salinization and its reasons in the different scale geomorphology units. On the base of field survey and GPS location and soil sample analysis from May 23 to May 29 in 2002, statistical analyses are used to study the differences of total salt content, pH, organic matter, Cl-/SO42-, HCO3-/(Cl- SO42-), and (K Na )/(Ca2 Mg2 ) of soils in the different geomorphology units. Both Kruskal-Wallis Test and Median Test are used to determine if above six parameters differ from each other in geomorphology units with different scales. The research results show that the soils in the neoteric and modern Yellow River Delta are affected strongly by salinity, which belong to coastal chloride type saline soil, and lack organic matter, and are basic. With the depth of soil increasing (0cm~10cm, 10cm~30cm and 30cm~60cm), the degree of salinization becomes less severe; Characteristics of soil salinization in the different geomorphology units with the same scale differ from each other, generally, with the scale lessening (from the first to the fourth level of geomorphology unit) these kinds of differences become quite apparent. Only pH is different between the first level of geomorphology units, and from the second to the fourth level of geomorphology units total salt content of soils in the different geomorphology units are different, and with the depth of soil increasing HCO3-/(Cl- SO42-) and (K Na )/(Ca2 Mg2 ) in the different geomorphology unit also become different.