ABSTRACT
Summary The purpose of this study was to investigate the possibility of silage corn cultivation by means of minimum tillage for renovating degraded pasture in Hokkaido, Japan. Corn (Wasehomare, a leading variety for silage in Hokkaido) was planted, in 4 replicates, on 23 May 1978 on the experimental farm of the Obihiro University of Agriculture and Veterinary Medicine under the conditions of no tillage, strip tillage, and conventional tillage. Plant density was 75 × 25 cm. Fertilizers applied were N, P2O5, and K2O, at rates of 120, 150, and 100 kg/ha. Herbicides used were 5% EPTC, 10 kg/ha, and 47.5% atrazine, 2 kg/ha. Dry-matter yield on the no-tillage plot was lower than on the strip-tillage or the conventional-tillage plot. There was no significant difference between the strip-tillage and conventional-tillage plots statistically. Percentage of vacant hills in the no-tillage plot was less than in the strip-tillage and conventional-tillage plots, though percentage of lodging in the no-tillage plot was greater. Dry weight of weeds decreased as tillage intensity increased. Intensity of light at ground level was lower in the no-tillage plot owing to the growth of weeds. Soil compaction was almost the same among these treatments. Silage corn cultivation by means of strip tillage instead of by the plough-plant method was found to be applicable for renovating degraded pasture in Hokkaido with the use of effective herbicides. Strip tillage is advantageous in reducing tillage intensity and maintaining forage yield; also, it is useful for soil improvement and weed control.
