干拓地土壌の物理的性質と其の改良法に関する研究(第4報) : 土壌の緊硬限界及び緊硬度の測定法に関する一考察(II)乾土及び湿土の緊硬度について
1956 年 27 巻 3 号 p. 123-127
詳細
1956 年 27 巻 3 号 p. 123-127
It is the purpose of this paper to study the methods for evaluating the consistency of dry and wet soil and their significance as a measure of soi1 tilth. Degree of penetration is measured by the force required to penetrate a standard needle into the soil sample. To find the ultimate breaking strength, the soil is molded into a small cylindrical briquette and the force required to break the briquette at its center part, is measured. Crushing strength is measured with the same cylindrical briquette by the force required to crush it. Natural breaking strength is the force required to break the cyindrical bripuette prepared by wetting the soil by capillary. The results obtained with the heavy clay polder soils have shown that the tilth of Gypsum- and Krilium- treated soils and also of pastured soils was more favourably improved as compared with that of standard soils.
