The Effect of Weeds on Rice in Paddy Field Ⅱ. Stage of Weed Emergence

水田雜草對水稻之影響　Ⅱ雜草之發生時期

張萬來(W. L. Chang)

《中華農業研究》 19卷4期 (1970/12) Pp. 26-31

https://doi.org/10.29951/JARC.197012.0004

摘要

嘉義農業試驗分所於民國58年第1、2期作在網室內調查三種主要水田雜草在不同時期發生時，對水稻爲害之情形。初步結果顯示在第1期作水稻，雜草若在插秧後15、30、45與60日發生時可分別減產68.7、46.7、28.1與11.0%，第2期作水稻，其產量只因插秧後10與20日發生之雜草而減產52.5與13.1%，但其產量卻不受在30與40日萌發雜草之影響。早期與後期萌發之稗草與三角草影響水稻產量之程度較鴨舌草爲大。不同時期萌發之雜草在不同肥力條件下減低稻谷產量之程度相若，稻谷產量構成因素中每株穗數與每穗粒數受雜草爲害之程度最爲嚴重，而百粒重與稔實率則不受影響。

並列摘要

The effect of weeds emerged at different stages on transplanted rice was investigated in both crops of 1969. Weeds emerged at 15, 30, 45, and 60 days after rice transplanting reduced grain yield of rice by 68.7, 46.7, 28.1, and 11.0% respectively in the first crop. In the second crop, weeds emerging at 10 and 20 days after transplanting caused yield reduction of 52.5 and 13.1% respectively, but weeds emerging at 30 and 40 days after tansplanting did not affect the grain yield of rice. Early- and late-emerging Echinochlor crusgalli and Cyperus difformis reduced more grain yield of rice than those of Monochoria vaginalis. The degree of damage caused by weeds emerging at different rice growing stages was not affected by fertility levels. Among components of yield, weeds affected only the number of panicles per plant and the number of grains per panicle, but not the 100-grain weight and the fertility percentage.