Abstract
In this study we practiced a joint experiment on tillage methods (PT, RT and NT) and soil types (volcanic L, volcanic SiC and sandy LS) simultaneously throughout the three places (Tokyo, Niigata and Shimane) from April in 1988 to June in 1991. In this paper we report the experimental results on six cropping for three years (crops=dent corn in summer and barley in winter) at volcanic SiC soil.
1) The emergence rate of NT was higher than other plots, and the rate of RT was lower at barley of fourth cropping. At dent corn of fifth cropping, there was no difference of emergence rate on the field between PT and RT, and the rate of NT was lower excessively than other plots.
2) Significant differences of the grain yield of dent corn were not observed in plots at the third cropping. The grain yield of barley decreased annually in every plots, but the rate of yield reduction of NT was the minimum among three plots. Significant differences of the grain yield among all plots were observed at the sixth cropping.
3) The quantity of weed of NT at the sixth cropping was smaller than those of PT and RT.
4) Significant differences of soil hardness (penetrating resistance) were observed in depth and plots. Soil hardness of NT were higher than other plots because of passed four months from the final tillage. In the results of soil hardness changes during one cropping, the hardness of RT approached the level of NT in depth of 20-30cm after two months from the final tillage, but the hardness of PT kept the effect of tillage untill each harvest.
5) No-tillage farming in continuous barley production at volcanic SiC soil was thought to be an effective system because of higher rate of emergence.
