Abstract
A research reported herein was carried out to determine the effect of soil moisture on emergence and growth of principal twelve species of annual weeds on upland fields. Results obtained are summarized as follows.
1. Optimum soil moisture for emergence of each species was little different, and it ranged from 70 to 85 percent of the maximum water holding capacity.
2. Optimum soil misture for growth of Cyperus iria and winter annual weeds was near upon the maximum water holding capacity. As to the other summer annual weeds, it ranged from 70 to 85 percent of the maximum water holding capacity.
3. Emergence and growth of weeds was suppressed by higher or lower soil moisture than the optimum soil moisture, the tendency influenced was different on weed species. Therefore, those weed species were grouped into four classes.
