除草剤の連用が開墾畑ミカン園の下草植生に及ぼす影響

概要

論文の詳細を見る
Experiments were carried out from 1975 to 1979 in a reclaimed hillside grove planted with satsuma mandarin trees in Ohita Prefecture, Kyushu. Treatments included three rotations of a combination of two herbicides; paraquat/propanil-carbaryl (short residual effect), asulam/ ametryn (intermediate residual effect) and bromacil/dichlobenil (long residual effect), and a mowed check (Table 1). Herbicides were applied three times a year for three years, and thereafter all the plots were managed by mowing. Mowing was practiced four times a year. The percentage of green cover was lowest in the bromacil/dichlobenyl plot but highest in the mowed check during the treatment period, and this tendency was still apparent even after a year of successive mowing in all the plots (Fig. 1). Values of the frequency index for the community coefficient which indicates the similarity degree in the floristic composition between plots, decreased with the increase of the time of herbicide application, although they fluctuated periodically (Fig. 3). The floristic composition of each plot was possibly characterized by both the kinds of species which appeared and disappeared in the plot (Table 2). The rate of annual weeds became lowest, while that of rhizomatous species was highest, in the bromacil/dichlobenil plot (Tables 2 and 5). Annual weeds were most abundant in the paraquat/propanil-carbaryl plot: The number of species was greatest and the seedling density was highest (Fig. 2, Table 3). Rate of wind-dispersed species was also high in this plot (Table 4). The trend observed in this trial suggests that the succession which occurs under chemical weed control is probably induced by properties of herbicides such as selectivity, duration of residual effect and soil surface conditions after treatment, and accelerated by the subsequent competition among species. The growth of satsuma mandarin trees and fruits was promoted only in the bromacil/ dichlobenil plot, but most reduced in the mowed check (Table 7). No significant difference was detected in the Brix index and titratable acidity in the fruit juice.
日本雑草学会の論文
1987-10-30

除草剤の連用が開墾畑ミカン園の下草植生に及ぼす影響

スポンサーリンク

概要

著者

関連論文

スポンサーリンク