Studies on the Available Uses of Pan-Breaker (III)

Abstract

This paper reports results of the investigations which were carried out in 1959 at the experiment farm of Hokkaido University to study on the lasting effects of pan-breaking for the first year after the treatment. In these plots, the pan-breaking was practised in last fall, and results for the first period of the study, concearning to the physical properties of soil before and after the pan-breaking, were reported in Journal of the society of Agricultural machinery, Japan, Vol. 2, No. 2, 1959.
the results in 1959 are as follows, ;
1) The lasting effects of pan-breaking upon the physical properties of soil may be discriminated by both sounding porosity rate of soil and soil resistance of penetration which is measured with penetrometer.
2) It was found that the soil which was loosened by the pan-breaker should be settled down during eight months after the treatment, and porosity rate became intermediate value between before and after the pan-breaking. Moreover, this value was maintained at least for three months running.
3) The soil resistance of penetration just above the bottom of the loosened soil was less than 10kg for the eighth and eleventh month after the treatment.
4) Soil compaction caused by tractor traffic has evidently reduced the lasting effects of the pan-breaking.