On the Difference of Soil Layers Hardness Caused by the Several Kinds of Chemical Fertilizers and the Two Kinds of Crops

The Observation, Experiment and Research in the Continuous Yearly Use Test Field of Three Major Nutrients of Chemical Fertilizers

Abstract

The transitions of soil physics caused by several kinds of chemical fertilizers and two kinds of crops in the continuous yearly use test field of the three major nutrients of chemical fertilizers were researched by a Hasegawa type soil penetration tester, paying attention to the hardness of the soil layers. The test crops are soybean and corn.
The hardness of the soil layers is shown commonly by the degree of softness in the case of a Hasegawa type soil penetration tester, but the writers indicated the necessary number of knocks (drops of a heavy plumb) to he penetrated at every ten centimeters depth of soil layer.
The number of knocks needed to penetrate soil layer from field surface to one meter depth, and at intervals of each ten centimeters of unit depth in the vertical direction of soil layer was examined by a statistical analysis.
As a result of these examinations, significant differences by several kinds of chemical fertilizers were not recognized within the same crop test fields, hut were recognized between different crop test fields. It means that the differences of soil layer hardness are induced by the two different crops.