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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.
Soil freeze-thaw characteristic curve is an important parameter to reflect the law of water, heat and salt migration during the freeze-thaw process, as well as the strength of permafrost and the thermal properties of frozen soil.In order to study the migration of soil nutrients during soil freezing and thawing, Method was used to measure and analyze the freeze-thaw curves of soil samples with different concentrations of ammonium sulfate solution, potassium dihydrogen phosphate solution and potassium chloride solution.The results show that the influence of potassium dihydrogen phosphate solution on soil freeze-thaw curve is not affected Clearly, potassium chloride solution has the most obvious effect, followed by ammonium sulfate solution.The second mutation point appears in the freezing-thawing characteristic curve of some samples added with potassium chloride solution and some samples added with ammonium sulfate solution. Hysteresis is commonly found in the freeze-thaw curves for each sample, and the temperature range in the clear hysteresis decreases with increasing concentration of the added sample. When the sample concentration is the same, the hysteresis is added to the potassium chloride solution Obvious interval between the lowest temperature range, followed by adding ammonium sulfate solution, adding the highest potassium dihydrogen phosphate solution.