Studies on the Available Uses of Pan-breaker (VI)

Abstract

The results of soil resistance for penetration in 1960 in Nemuro-kushiro district (East Hokkaido) were reported in previous paper (Report V). This paper reports about the results of the investgation of physical properties of soil and the growth and yields of crops in spring and autumn. The trouble for root development was caused by the soil freezing, the hard pan, and the layer of volcanic ash in the soil. The kind of crops investigated were grass, sugar beet, dent corn, rutabaga and oats. Results are as follows:
(1) The thawing of soil continues to early in May at this region, and then soil must be plowed rapidly after thawing. The soil water does not filtrate late in April. In the mechanically treated plots, apparent specific gravity is 0.5 to 0.6. This value is approximately 0.1 less than that in the untreaded plots. Soil porosity is also higher in the treated plots.
(2) Permeability at the depth of 30 to 45cm is high in the treated plots. In the low swampy land, however, the difference by treatment is not found clearly.
(3) Any crops in the low swampy land did not grow before treatment, but considerable amount of sugar beet was yielded by the treatment. This is due to a drainage effect. The yields of the grass (Timothy) is evidently high at the old farm which has been cultivated for about 30 years.