Studies on Evaluation Method for Physical Properties of Soil after Jillage

[1]块度分布的研究(1)讨论了对数正态Rosin-Rammler分布、高丁-舒曼分布和威布尔分布对块度分布的逼近。在威布尔分布近似的情况下，通过改变形状参数的取值，得到了满意的结果。(2)取样器直径的选择必须考虑土块的平均直径。在旋耕条件下，取样器直径以200 mm以上为宜。[2]土壤翻转评价研究(1)利用氯化钾测定土壤电导率的变化，成功地评价了土壤翻转率。(2)用该方法检测了上切旋耕与下切旋耕翻耕的差异。(3)耕作后土壤向前移动量大于25 cm，向后移动量大于50 cm。

[1] Studies on clod size distribution (1) We discussed the approximation of the clod size distribution by log-normal Rosin-Rammler's, Gaudin-Shuman's and Weibull's distribution. In case of the approximation by Weibull's distribution, we obtained satisfactory results by means of changing the value of its shape parameter. (2) The diameter of sampler must be selected considering the average diameter of soil clod. In the case of rotary tillage, it is found that the diameter of sampler should be 200 mm on more.[2] Studies on evaluation about turning of soil (1) We succeeded in evaluating the turning percentage of soil by means of measuring the change of Ec (electric conductivity) using potassium chloride. (2) We detected the differenece of turning between up-cut rotary tillage and down-cut rotary tillage using the method. (3) The forward movement of soil after tillage is more than 25 cm and the backward one is more than 50cm.