摘要
土壤冻融特征曲线是反映土壤冻融过程中的水、热、盐迁移规律以及冻土强度、冻土的热性质的重要参数.为了研究土壤冻融过程中土壤养分的迁移规律,采用核磁共振法对加入不同浓度的硫酸铵溶液、磷酸二氢钾溶液和氯化钾溶液的土样的冻融特征曲线进行了测定和分析.结果表明磷酸二氢钾溶液对土壤的冻融特征曲线影响不明显,氯化钾溶液的影响最明显,硫酸铵溶液的影响次之.加入氯化钾溶液的部分试样,以及加入硫酸铵溶液的部分试样的冻融特征曲线出现了二次突变点.滞后现象普遍存在于各个试样的冻融特征曲线中,滞后明显区间所处的温度范围随所加入的溶液浓度的增高而降低.当加入试样的溶液浓度相同时,加入氯化钾溶液的滞后明显区间所处的温度范围最低,加入硫酸铵溶液的次之,加入磷酸二氢钾溶液的最高.
The characteristic curves of soil freezing and thawing reflect the strength, thermal properties and water and solute transport regularity. In order to study the migration of soil nutrient during soil freezing and thawing, the freezing and thawing curves of umber soil, mixed with solutions of (NH-4)-2SO-4, KH-2PO-4 and KCl, respectively, were measured by nuclear magnetic resonance. It was found that the influence of the concentration of KH-2PO-4 on the freezing and thawing curves is insignificant, but that of KCl and (NH-4)-2SO-4 are significant, especially that of KCl. Secondary discontinuous point was found on freezing or thawing characteristic curve of some samples mixed with either KCl or (NH-4)-2SO-4 solutions. Hysteresis widely exists in the freezing and thawing characteristic curves. The temperature range of the obvious hysteresis zone decreases with solute concentration increasing. For the same concentration, the temperature range of the obvious hysteresis zone is the minimum for the samples mixed with KCl solution, followed by that mixed with (NH-4)-2SO-4, and is the maximum for the samples mixed with KH-2PO-4.
出处
《冰川冻土》
CSCD
北大核心
2004年第4期440-448,共9页
Journal of Glaciology and Geocryology
基金
冻土工程国家重点试验室开放基金项目(SKLFSE200303)
辽宁省博士后基金项目
国家自然科学基金项目(40272102)资助
关键词
未冻水
土壤养分
核磁共振
突变点
滞后现象
unfrozen water
soil nutrient
nuclear magnetic resonance
discontinuous point
hysteresis
