抄録
Chinese milk vetch (Astragalus sinicus L.) was seeded at various rates and on different dates, to study the relation between the microclimate in the tuft and the development of the Sclerotinia rot.
In the sunny daytime, the air temperature within the tuft of milk vetch, especially in the plots of thick stands, was lower than in the temperature screen. While, in the daytime with heavy cloud or at night, the temperature within the vetch tuft was higher than in the temperature screen, in proportion to the density of the stand.
The temperature of the soil at 1cm depth showed the same tendency of fluctuation with the temperature in the tuft. Accordingly the extreme differences of air and soil temperatures by day and night was least in the tuft of the thickest stand.
The air humidity in the tuft was higher than in the temperature screen and was highest in the plot of thick stand. The quantity of dew formed at night on the plants per unit area was greater in the plot of thick stand than in the thin stand, but vice versa when calculated on the basis of individual plant.
The incidence of Sclerotinia rot was high in the plot of thick stand of milk vetch. It may be explained by the microclimatical difference above described.
