Effect of depth of submergence on the control of barnyard grass and the yield of rice grown in pots
1933
Jones, J.W.
The locally known "white" barnyard grasses that have large seeds emerged each year through 2, 4, 6, 8, and 10 inches of water with similar stands. The time required for the seedlings to emerge varied with the depth of water. Deep water delayed emergence and reduced the growth of white barnyard grass plants, but did not control them. The stands of common barnyard grasses on land continuously submerged 2, 4, 6, 8, and 10 inches deep, respectively, decreased with increased depths of submergence from 2 to 6 inches. Common barnyard grass seedlings did not emerge through 8 and 10 inches of water, although a few emerged through 6 inches of water. The control of common barnyard grass by continuous submergence appears to be the result of the interaction of several factors. Of these factors, high water temperatures resulting in a low oxygen pressure and shade from scum, algae, and plant growth are the most important. Seedlings in shaded warm water are unable to remain alive and vigorous owing to disturbed photosynthetic activity. Rice plants grown in soil kept in a "mucky" condition were shorter and produced fewer culms and much lower yields of grain and straw than plants grown on soil submerged 2, 4, 6, 8, and 10 inches deep, respectively. The highest average yield of grain was obtained from plants grown in soil submerged 4 inches deep. The largest average number of culms and the highest average yield of straw were obtained from the plants grown in soil submerged 6 inches deep. Plants grown on soil submerged 2 inches deep produced a smaller average number of culms and a lower average yield of grain and straw than plants grown in soil submerged 6, 8, and 10 inches deep, respectively.
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