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稻蔸夹稗时，夹蔸稗分蘖生长势远远强于水稻，其最高分蘖增长率夹蔸稗和水稻分别为１２６０％和６８０％；夹蔸稗的株高一般高于水稻４０～５０ｃｍ，覆盖在水稻的顶层，叶面积指数及根长和根表吸收面积亦大于水稻，因此，夹蔸稗的生长势总是超过水稻。水稻分蘖盛期到抽穗期内稗／稻干物质比在１．６～２．５之间。水稻不同夹稗蔸率试验结果表明，随着夹稗蔸率的提高，分蘖数显著减少，减产幅度加大。当夹稗蔸率为１００％时，分蘖数比对照减少５０％左右，减产５０％以上。以水稻夹稗蔸率百分数为自变量（Ｘ），以水稻有效穗减少百分率（ｙ１）或稻谷减产百分率（ｙ２）为依变量，它们之间的关系均符合曲线方程为待定参数），其具体表达式如下：威优６４，；湘早籼７号，
When the barnyardgrass was barnyardgrass, the tiller growth potential of barnyardgrass was much higher than that of rice, and the highest tiller growth rate was 1260% and 680% for barnyardgrass and rice, respectively. The plant height of barnyardgrass was generally higher than that of rice for 40-50 cm, Covering the top layer of rice, leaf area index and root length and root surface area were also larger than that of paddy rice. Therefore, the growth potential of barnyardgrass was always higher than that of rice. The ratio of barnyardgrass / rice dry matter in tillering stage to heading stage was between 1.6 and 2.5. The results of rice experiments with different rates of barnyardgrass showed that as the rate of barnyardgrass increased, the number of tillers significantly decreased and the rate of decrease was increased. When the rate of barnyardgrass was 100%, the number of tillers was reduced by 50% than the control, and the yield was reduced by 50% or more. The rice percentage of barnyardgrass was taken as the independent variable (X), and the percentage of reduction of effective panicles (y1) or the percentage of reduced rice yield (y2) was dependent on the change of rice yield. The relationships between them were in accordance with the curve equation as undetermined parameters. The expression is as follows: Wei You 64 ,; Xiang early indica 7,