冬小麦田大穗看麦娘种群动态及对小麦产量的影响

Population dynamics of black-grass Alopecurus myosuroides in wheat fields and its effect on wheat yield components

为明确麦田杂草大穗看麦娘Alopecurus myosuroides的田间种群发生动态规律,采用固定样方和随机样方取样方法于2013—2015年在山东省济南市研究了冬小麦田大穗看麦娘田间种群的萌发和生长动态,并分析了不同密度大穗看麦娘对小麦产量及其构成因素的影响。结果表明:在济南市小麦播后20~40 d为大穗看麦娘出苗高峰期,至11月下旬出苗量占全年出苗总量的97.1%。11月上旬,大穗看麦娘开始出现分蘖,至翌年4月上中旬结束,分蘖数平均每株为6.3个,比小麦多3.1个。3月下旬大穗看麦娘开始拔节,4月中旬平均株高超过小麦,5月下旬平均株高达到75.6 cm,高出小麦2.5 cm。5月上旬大穗看麦娘单茎平均鲜重达到最大为1.7 g,小麦为12.6 g。大穗看麦娘出苗、株高、分蘖和鲜重的变化与小麦变化趋势一致,与时间、温度密切相关。随着大穗看麦娘密度的增加,小麦产量急剧下降,当密度达到420株/m^2时,小麦产量损失率高达65.8%。大穗看麦娘对小麦产量构成因素中的穗密度影响最大,其次是穗粒数,对千粒重影响不显著,当密度为420株/m^2时,小麦穗密度减少55.2%,穗粒数减少26.4%。

To determine the population dynamics of black-grass Alopecurus myosuroides. Germination and growth dynamics of black-grass in winter wheat fields were determined by fixed quadrat sampling and random sampling in Jinan City, Shandong Province. Influences of different black-grass densities on winter wheat yield and its components were also investigated. The results showed that the peak of blackgrass seedling emergence appeared 20-40 d after wheat seeding. By the end of November, the germination amount accounted for 97.1% of the total emergence. Tillers appeared in early November and ended in early April of the next year. Black-grass formed averagely 6.3 tillers per plant, 3.1 more than wheat.In late March, black-grass seedling entered jointing stage. Black-grass was higher than wheat after midApril, and reached 75.6 cm in late May, 2.5 cm higher than wheat. The average fresh weight of each culm of black-grass and wheat were 1.7 g and 12.6 g in early May, respectively. The dynamics of emergence, tillering, height and fresh weight of black-grass were consistent with the trend of wheat, and were closely related to time and temperature. With the increase of black-grass density, the yield of wheat decreased sharply. When the density reached 420/m2, the yield loss rate was as high as 65.8%.The weeds had the largest effect on spike density factors in wheat yield, followed by the grain number per spike, but no significant effect on 1 000-grain weight. Spikes and grain number per spike of wheat were reduced by 55.2% and 26.4% when the black-grass number rose from 0 to 420 plants/m2.