1992 Volume 27 Issue 2 Pages 111-117
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, Niiga taand shimane) from April in 1988 to June in 1991. In this paper we report the experimental results on six croppings for three years (crops=dent corn in summer and barley in winter) at volcanic L soil.
1) Significant differences of the grain yield of dent corn were not observed in plots at the third and fifth croppings though they didn't reach to an ordinary yield level because of damages by tornado and hail. The grain yield of barley of NT was the maximum in plots at the second cropping, but it decreased at fourth cropping. It decreased more sharply at the sixth cropping. There were no differences in harvest index of the plots.
2) The quantity of weed of NT at the fourth and sixth croppings were more than those of PT and RT. The dominant species of weed were commonly observed in the plots.
3) 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 an half year from the final tillage. In the results of soil hardness changes during one cropping, the hardness of PT and RT increased after one month from the final tillage.
4) Significant differences of soil pH were not observed in depth and plots.
5) From the viewpoint of crop yield, no-tillage farming is profitable to the early cropping, so a renewing tillage to NT become to be important in practical.
