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北京郊区盐碱地主要分布在东南郊通县、大兴两县,占全市盐碱地总面积75%。一、北京盐碱土类型及其特性据初步調查,京郊的主要盐碱土的类型大致可概括如下几种:1.以重碳酸盐和硫酸盐或重碳酸盐和氯化物为主的砂碱土(白碱土)这种土壤春秋两季,地面常有盐霜,春季返盐,秋后返硝,所謂“冷硝热盐”。0~20厘米土层中一般地平均含盐量0.1~0.2%上下。在易溶性盐类中HCO_3~-占阴离子毫克当量的50%,其次为SO;或Cl~-。在阳离子中以Na~+占优势,約占50%,其次是Mg~(++)和Ca~(++),潜水矿化
Suburbs in Beijing suburbs are mainly distributed in the southeastern suburbs of Tong County, Daxing two counties, accounting for the city’s total area of 75% of saline land. I. Types and Characteristics of Saline-Alkali Soils in Beijing According to the preliminary investigation, the types of the main salinities in the suburbs of Beijing can be broadly summarized as follows: 1. Sands that are dominated by bicarbonate and sulfate or bicarbonate and chloride Alkaline earth (white alkaline earth) This soil spring and autumn two seasons, the ground often salt cream, spring back to salt, fall back to nitrate, the so-called “cold nitrate hot salt ”. 0 ~ 20 cm soil layer generally average salt content of 0.1 ~ 0.2% up and down. In soluble salts HCO_3 ~ - accounted for 50% of the anion milligram equivalent, followed by SO; or Cl ~ -. In the cation Na ~ + is dominant, accounting for about 50%, followed by Mg ~ (++) and Ca ~ (++), diving mineralization