甘肃景电灌区盐化土壤的吸湿系数与凋萎湿度及其预报模型

调查研究了甘肃景电灌区盐化土壤的吸湿系数和凋萎湿度及其与土壤全盐、电导率和物理性粘粒含量的关系。结果表明盐分对土壤吸湿系数具有显著影响 ,盐土的吸湿系数可达 1 7 93%～ 38 30 % (重量含水量 )。随着土壤全盐量的降低 ,物理性粘粒含量对吸湿系数的影响逐渐增大。盐分组成对盐土和盐化土壤的吸湿性影响很大 ,氯离子 >钠离子 >镁离子≥钙离子 >硫酸根离子。盐分对土壤凋萎湿度的影响也达极显著水平 ,但凋萎湿度不如吸湿系数对盐分敏感。盐分离子组成对凋萎湿度的影响与其对吸湿系数的影响相似 ,氯离子>钠离子 >硫酸根离子 >镁离子 >钙离子。根据凋萎湿度与吸湿系数之间的关系以及凋萎湿度与物理性粘粒含量、全盐和电导率之间的关系 ,本文提出了预报盐化土壤凋萎湿度的三种模型 ,经检验获得了较为理想的结果

HYGROSCOPIC COEFFICIENT AND WILTING POINT OF SALT-AFFECTED SOILS IN JINGDIAN IRRIGATION ZONE, GANSU

The paper addresses hygroscopic coefficient and wilting point(with barley,H ordeum sativum Jess,as an indicator) and their relations to soil particle<0.01mm content and salt content of saltaf ected soils in Jingdian irrigation zone,Gansu.The results il ustrated that salt content significantly af ected hygroscopic coefficient.In soils with total salts of 7.58~17.39g kg-1 it could reach 17.39%~38.30%(gravimetrically).With decrease in salt content,effect of particle<0.01mm content on hygroscopic coefficient increased.The influence of salt component on hygroscopic coefficient varied in the order of Cl^->Na⁺>Mg²⁺\Ca²⁺>SO₄^2-.It seems that there was no great difference between the effects of particle<0.01mm content and salt content on wilting point,which,however,both reached a significant level.Comparat ively,wilting point was less sensitive to salts content than hygroscopic coef icient was.The effect of salt components on wilting point was similar to that on hygroscopic coefficient.On the correlation of wilting point with hygroscopic coefficient,particle<0.01mm content,salt content and electrical conductivity,three models were presented to predict the wilting point of salt-affected soils in the zone.