麦田雀麦发生动态及其对小麦产量的影响

雀麦(Bromus japonicus)是一种越冬性一年生杂草,是我国北方冬小麦田发生最严重的禾本科杂草之一,对小麦造成严重减产。为明确雀麦在我国冬小麦田的田间发生动态规律,于2013-2015年在山东省泰安市雀麦发生严重的冬小麦田进行相关试验。采用固定样方和随机样方取样的方法,研究冬小麦田雀麦的出苗规律及其在田间的消长动态,同时研究不同密度雀麦对小麦产量的影响。结果表明,小麦播种后7~30 d为雀麦的出苗高峰期,至12月上旬出苗量占总出苗总量的85.3%。11月中旬,雀麦开始分蘖,平均分蘖数为4.8个/株,比小麦多1.3个/株。3月下旬雀麦生长速度加快,4月下旬平均株高超过小麦,5月中下旬平均株高达到115.0 cm,高出同期小麦24.1 cm。5月中旬,雀麦与小麦单株平均鲜重趋于稳定,分别为17.24、37.72 g。雀麦与小麦在株高、鲜重等方面的变化趋势基本一致,与外界温度的变化密切相关。当雀麦密度为5株/m^2时,小麦产量损失率达5.35%,表明少数雀麦即可对小麦产量造成显著减产;随着雀麦密度的增加,小麦产量快速下降,其对小麦产量的影响主要表现在小麦的有效穗密度上,对小麦的千粒质量与穗粒数则影响较小。当雀麦密度为640株/m^2时,小麦产量损失率为36.81%,小麦穗密度减少35.69%。

The Occurrence of Japanese Brome (Bromus japonicus) in Wheat Fields and Its Effect on Wheat Yield

Japanese brome(Bromus japonicus) is a winter annual weed commonly found in wheat fields in China,especially in the northern region where it causes obvious yield losses. To determine the field dynamics of Japanese brome in wheat fields,experimentswere conducted from 2013 to 2015 in a field seriously infested in Tai’an. The dynamics of emergence,tillering,plantheight,fresh weight and its competitive effect on the yield of winter wheat was surveyed by both fixed and random quadrat sampling. The peak of Japanese brome seedling emergence occurred 7~30 d after wheat seeding. In early December,germinationrepresented 85. 3% of the total. Tillering began in mid-November and was completed at the end of March of the following year. Japanese brome had on average 4. 8 tillers per plant,1. 3 more than wheat. In late March,Japanese brome speeded up growth and became taller than wheat after late April. Japanese brome reached 115. 0 cm per plant on average in late May,24. 1 cm taller than wheat. The average fresh weight of Japanese brome and wheat estabilized at 17. 24 g and 37. 72 g,respectively. The dynamics of height and fresh weight of Japanese brome were consistent with wheat,and were closely related to the changing temperature. When Japanese brome density is 5 spikes/m^2,the yield losses of wheat are 5. 35% indicating that a few Japanese brome could result in a significant reduction of grain yield. With the increase of Japanese bromedensity,wheat yield rapidly declined.Japanese brome had the largest effect on spike density factors in wheat yield with smaller impact on 1000-grain weight and grain number per spike. When the density reached 640/m^2,the yield loss rate was 36. 81% and spike density of wheat declined 35. 69%.