Changing Characteristics of Salt Accumulation Patterns in the Soil Surface

通过对NaCl溶液饱和土壤样品油炸过程中盐的积累规律的研究，发现表征土壤表面蒸发与土壤悬浮液浓度关系的盐积累曲线具有显著的拐点A点。为了解释这一现象，在不同的干燥条件下进行了额外的盐积累实验。并进行了几种与盐积累有关的试验；即土壤溶液的干燥速率曲线模式和土壤溶液的运动特性。得到了以下结果：在a的拐点处，随着干燥温度的升高，蒸发量减小，但土壤溶液浓度的差异对蒸发量没有影响。利用土柱试验研究了不同土壤种类和不同土壤溶液浓度对盐渍化过程中土壤干燥特性的影响。结果表明，随着这些参数的不同，土壤干燥特性曲线的形态也不同。采用四种曲线研究了土壤溶液的运动；即不同划分层和不同干燥层的含水量分布，划分层的累积干燥速度与干燥层的关系，每划分层的干燥速度与干燥层的关系。认识到这些曲线对研究盐积累是有效的，但实验精度有待提高。

It was recognized that salt accumulation curves represented relation between evaporation from soil surface and concentration of soil suspension at each divided layers have the remarkable inflection point named point of A by the study which was performed to determine the salt accumulationpatterns in the frying process of soil specimens saturated with NaCl solution. In order to explain this phenomenon additional experiments for salt accumulation were performed at the different drying conditions. And some kinds of experiments related with salt accumulation were tried; i.e. patterns of drying rate curves to soil solution and movement characteristics of soil solution.The following results were obtained.1. Volume of evaporation decreased in the increase of drying temperature at the inflection point of A. But, the difference of concentration of soil solution did not have an effect on the volume of evaporation.2. The effect of differnces in the kinds of soils and concentration of soil solution on the drying characteristics of soil s during the process of salt accumulation was studied experimentally using soil columns. It was recognized that the configuration of curves of the drying characteristics of soils varied with the differnce in these parameters.3. The movement of soil solution was studied by four kinds of curves; i.e. water content distribution at the different divided layers and at the different drying levels, and relation between accumulated drying velocity of divided layers and drying level, and relation between drying velocity at each divided layer and drying level. It was recognized that these curves were effective to study the salt accumulation and that experimental accuracy is need to increase.