新疆核桃-小麦间作麦田杂草组成及群落特征
Species composition and community characteristics of weeds in wheat fields under walnut-wheat intercropping system in Xinjiang

为明确新疆核桃与小麦间作对麦田杂草种类及群落结构的影响，于2012—2017年对新疆南疆核桃-小麦间作、单作麦田杂草发生情况进行了调查。结果表明，南疆麦区杂草有39种，隶属14科33属，其中以菊科、禾本科、藜科为主；优势杂草有9种，分别是灰绿藜Chenopodium glaucum L.、稗草Echinochloa crusgalli（L.）Beauv.、播娘蒿Descurainia sophia（L.）Schur.、扁蓄Polygonum aviculare L.、硬草Sclerochloa kengiana L.、田旋花Convolvulus arvensis L.、离蕊芥Malcolmia africana（L.）R.Br.、小蓟Cephalanoplos segetum（Bunge.）Kitam.、苣荬菜Sonchus brachyotus DC.；与小麦单作田相比，核桃-小麦间作麦田杂草物种丰富度及Shannon-Wiener指数较高，2017年物种丰富度最高达27种，代表杂草优势集中性的Simpson指数则是小麦单作田高于核桃-小麦间作麦田，2013年高达0.32；核桃-小麦间作有利于麦田播娘蒿、苣荬菜和离蕊芥发生，但不利于萹蓄发生，其它5种优势杂草在间作和单作麦田的发生密度显著差异。
In order to determine the effect of walnut-wheat intercropping pattern on wheat weed species and community characteristics in southern Xinjiang, the weeds of walnut-wheat intercropping fields were investigated from 2012 to 2017. The results showed that there were 39 weed species altogether, which belonged to 33 genera in 14 families. The nine dominant species in wheat fields in Xinjiang were Chenopodium glaucum L., Echinochloa crusgalli (L.) Beauv., Descurainia sophia (L.) Schur., Polygonum aviculare L., Sclerochloa kengiana L., Convolvulus arvensis L., Malcolmia africana (L.) R. Br., Cephalanoplos segetum (Bunge.) Kitam., and Sonchus brachyotus DC. The weed species richness and Shannon-Wiener index in walnut-wheat intercropping fields were higher than those in monoculture wheat fields, and the highest species richness was 27 in 2017. The Simpson index, representing the dominant concentration of weeds, was higher in monoculture wheat fields than in walnut-wheat intercropping fields, reaching 0.32 in 2013. The walnut-wheat intercropping was beneficial to the occurrence of D. sophia, S. brachyotus and M. africana in wheat fields, but it was not conducive to the occurrence of P. aviculare; there was no significant difference in the occurrence density of the other five dominant weeds between these two planting patterns.