【作者】 赵延存；

【导师】 刘凤权； 娄远来；

【作者基本信息】 南京农业大学 ， 植物病理学， 2006， 硕士

【摘要】 稻茬移栽油菜是长江下游地区油菜的主要种植方式。近年来，稻茬油菜田杂草以禾本科为主，同时阔叶杂草发生量逐渐上升，对油菜生产造成严重危害。目前，胺苯磺隆是防除油菜田禾本科与阔叶混生杂草的首选除草剂，但胺苯磺隆残效期长，易对后茬作物(如水稻)产生药害。本文研究了不同耕作制度油菜田杂草发生规律，稻茬油菜田杂草群落与油菜的竞争互作，含有胺苯磺隆的复配剂21％油壮胶悬剂(SC)对稻茬移栽油菜田杂草的防除效果及其对后茬水稻的安全性。结果如下： 通过对水稻茬、玉米茬和棉花茬移栽油菜田杂草发生规律的调查分析，结果表明耕作制度的不同导致三种油菜田杂草群落结构和大小差异巨大。稻茬油菜田杂草群落以喜湿性禾本科杂草日本看麦娘(Alopecurus japonicus Steud.)为优势种，同时伴有中生性阔叶杂草巢菜(Vicia sativa)、荠菜(Capsella bursa-pastoris)等；棉花茬和玉米茬油菜田杂草群落以中生性和旱生性阔叶杂草为主，并且比稻茬油菜田杂草发生量小很多。在冬前，三种耕作制度油菜田杂草均有一个出苗主高峰，相应形成一个杂草密度高峰；开春后，都有少量杂草出苗，玉米茬和棉花茬油菜田杂草密度略有增加，稻莅油菜田禾本科杂草大量分蘖，杂草密度有较大幅度增加。 对稻茬移栽油菜田杂草与油菜的竞争互作研究表明，杂草生物量在3月份之前增加极缓慢，进入3月中旬以后直线上升；与低密度油菜相比，高密度油菜对杂草生物量的增加有明显抑制作用。与对照相比，在油菜开花结荚期大量杂草的干扰使油菜每株角果数、角果干重、茎干重下降21.7～36.5％，分枝数、千粒重等也有不同程度的下降，而前期存在或后期萌发的杂草对油菜影响较小。全生育期保持有草处理的高、低密度油菜产量损失率分别为13.8％、59.0％，差异极显著，说明适当增加油菜密度能够显著减轻其产量损失。杂草的存在也影响了干物质在油菜营养和繁殖器官中的分配比率，且高、低密度油菜表现不同。 复配除草剂21％油壮SC(由胺苯磺隆、乙草胺和精喹禾灵复配而成)能够同时对油菜田禾本科和阔叶草起到土壤封闭和茎叶触杀效果，且胺苯磺隆施用剂量降为其单剂的50％，提高了对后茬水稻的安全性。于12月上旬施用21％油壮SC100ml／667m~2，对供试稻茬移栽油菜田禾本科和阔叶杂草的株防效分别为97.4％和76.9％，鲜重防效分别为97.8％和87.2％，与有草对照相比增产43.8％，增产显著，综合效果好于25％胺更多还原

【Abstract】 Transplanted rape after rice is main planting pattern of rape in the lower reaches of Yangtze River. In recent years, grass weeds were dominant in transplanted rape fields after rice, and broadleaf weeds gradually increased. Rape production was endangered by those weeds. Ethametsul-furon was preferred herbicide that could effectively control grass and broadleaf weeds. But residues of ethametsul-furon in soil frequently harmed succeeding crops (eg. rice) due to its slow degradation. In this paper, we first studied occurrence law of weeds in different cultivation-system rape fields and competition of weeds with transplanted rape after rice, then control effect of Youzhuang 21% SC to weeds in rape fields and its security to succeeding rice. The results were as follows:Structure and magnitude of weed communities were completely different in transplanted rape fields after rice, maize and cotton. In transplanted rape fields after rice, hydrophilous weed Alopecurus japonicus was the dominant species, and there were also lots of mesophytic weeds , such as Vicia sativa and Capsella bursa-pastoris. In transplanted rape fields after maize and cotton, mesophytic and xeromorphic weeds dominated in weed communities. Weed magnitude was much less in transplanted rape fields after maize and cotton than that in transplanted rape fields after rice. Weeds had a emergence peak and a density peak before winter in transplanted rape fields. In spring, a few weeds emergenced, and weed density increased slightly in transplanted rape fields after maize and cotton. But weed density increased sharply in transplanted rape fields after rice because of a great deal of grass-weed tillers in spring.Weed biomass increased very slowly before March, but increased sharply after the middle of March. Compared with low density rape, high density rape clearly inhibited weed growth. Compared with the control, the numbers of pods, pods dry weight and stalk dry weight decreased 21.7-36.5% in treatments with vast weeds at the rape flowering-poding stage, and branches and 1000-grain weight also decreased at different degrees. But weeds at the early stage of rape and seedling weeds at the late stage of rape little affected rape. The更多还原