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不同轮作制度对定西地区农田杂草群落的影响 总被引：1，自引：0，他引：1
为探讨不同轮作制度对定西地区农田杂草群落的影响,采用倒置"W"九点取样法,调查了定西地区7种不同轮作制度下田间杂草的种类、数量、地上生物量等。在试验田发现11个科共15种杂草;从杂草发生密度、地上生物量上看,苦苣菜、藜是农田优势杂草,防除的目的杂草;不同轮作田的杂草群落由优势杂草组成;从不同轮作田杂草群落的物种多样性来看,马铃薯胡麻轮作马铃薯小麦轮作胡麻小麦轮作胡麻连作小麦胡麻轮作小麦马铃薯轮作胡麻马铃薯轮作;对不同轮作田杂草群落进行聚类,可分为四类。通过对不同轮作田中杂草的密度、地上生物量和综合优势度比的综合分析,可以看出胡麻连作、小麦胡麻轮作、马铃薯胡麻轮作、小麦马铃薯轮作中杂草的危害性较大。马铃薯小麦轮作、胡麻小麦轮作和胡麻马铃薯轮作对杂草有一定的控制作用。 相似文献
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在陇东旱塬区研究了全膜双垄沟播和露地玉米田杂草的消长动态,结果表明,全膜双垄沟播田杂草发生期(4月上中旬)较露地约提前1个月。全膜双垄沟播田杂草群落的物种丰富度及其密度分别呈"N"字形和"∧"形,均与露地相似,但其波动幅度明显大于露地,高峰期均明显早于露地。全膜双垄沟播和露地种植模式下,阔叶杂草物种丰富度和密度的波动幅度均远大于禾本科杂草。全膜双垄沟播玉米田阔叶杂草群落鲜质量及其单株鲜质量均呈"∧"形,而露地呈持续递增形,高峰期均明显早于露地,峰值均明显小于露地;全膜双垄沟播玉米田禾本科杂草群落鲜质量及其单株鲜质量波动幅度均远大于阔叶杂草,均与露地情形相反。杂草发生对全膜双垄沟播田集水、保墒及玉米生长发育均造成持续性危害,以玉米播后出苗期和玉米拔节至大喇叭口期危害最重,分别称之为第一、第二危害盛期。 相似文献
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黑龙江垦区大豆田由于多年使用氟乐灵、杜耳、拿捕净等以防除禾本科杂草为主的除草剂,使杂草群落发生明显变化,禾本科杂草发生基数下降,阔叶杂草比例上升。为了经济有效的控制大豆田草害,在前两年的试验基础上,1988年我们又进行了以克阔乐(又称眼镜蛇,通用名为Iactofen,商 相似文献
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1浅水藕田杂草的发生特点
1．1杂草发生时间长,具有明显的萌发高峰期
两年观察结果表明,浅水藕田杂草萌发有一个高峰期,高峰期出现的时间为栽种后10—20d,高峰期间的出草量占总草量的60．3％～69．5％。从各类杂草的萌发数量看,禾本科杂草和莎草科杂草主要集中在栽种后10～15d,其出草量分别占总草量的80．3％和76．8％,呈单峰型发生。阔叶草萌发表现为明显的双峰型,第一峰为浅水藕栽种后15～20d,出草量占总草量的51．9％,第二峰在栽种后30—35d,出草量占总草量的36．5％。 相似文献
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随着种植业结构调整，耕作制度的变化，杂危害已成为影响廊坊市大豆高产的主要因素一。全市大豆常年播种面积３万hm２，均不同度地受到杂草的危害。为了指导农民有效地治大豆田杂草，我们于２００１年开展了大规模普查工作。通过在大豆开花初期对不同土壤地，不同区域的大豆田杂草的调查，基本摸清本市大豆田杂草发生情况，并根据调查结果，出了防治杂草的策略。杂草种群发生动态根据本市地理特点和大豆田生产布局分别本市的北、中、南部选定３个县、区（香河县、次区、大城县）有代表性的大豆田，在大豆开前进行调查，共查９个乡（镇），３… 相似文献
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混合一年生杂草与大豆竞争临界期的研究 总被引：1，自引：0，他引：1
１９８６～１９８８年研究表明．大豆田混合一年生杂草从株高上可分为三个种群：以稗、苋为主的混合一年生杂草的春大豆田，无杂草期与大豆产量呈高度正相关，表现为Ｓ型曲线，方程为，认为无杂草临界期为大豆出苗后５周。杂草竞争持续期与大豆产量呈高度负相关，回归分析两年平均产量为倒Ｓ型曲线，方程为，杂草竞争持续临界期为大豆出苗后４周。结果表明大豆田除草的临界期为大豆出苗后４～５周，此期要保持大豆田基本无草状态，才能获得较高的产量。认为大豆田除草的最佳时期为大豆出苗后３～５周。 相似文献
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夏大豆田草害发生轻重的影响因素初探 总被引：2，自引：0，他引：2
通过1985～1991年的试验和典型田块调查,对耕作方式、播期、密度、秸秆还田以及除草剂等因素对夏大豆田杂草发生的影响作了粗浅的探讨。一、耕作方式 1987年夏大豆播后杂草萌发前,选近几年未深翻的豆麦连续轮作田,采取5点取样,每点0.11平方米,分层取土,再取样、水洗、过滤,统计杂草种子数。1987年小麦播种前,在同一田块人工翻土,深25厘米左右,1988年夏大豆田杂草萌发前,用同样方法统计各土层杂草种子数, 相似文献
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河北省冬小麦田杂草群落特征 总被引：3，自引：10，他引：3
为了明确河北省冬小麦田杂草的群落组成和结构,采用倒置"W"取样法对河北省7个地区146块冬小麦田的杂草进行了调查和物种多样性测度。结果显示,河北省冬小麦田有61种杂草,隶属于21科53属,播娘蒿、打碗花、荠菜、麦瓶草和麦家公是河北省冬小麦田的优势杂草。保定地区麦田杂草群落的物种丰富度最大;沧州地区麦田杂草群落的Shannon-Wiener指数和Pielou指数最大;廊坊地区麦田杂草群落的Gleason指数、Shannon-Wiener指数和Pielou指数最小,优势草种比较突出。经聚类分析和主成分分析,河北省冬小麦田杂草群落分为3组:石家庄、保定、邢台和廊坊的麦田杂草群落中耐旱杂草的相对多度较高;沧州和衡水的麦田杂草群落中耐盐杂草的相对多度较高;邯郸的麦田杂草群落中喜湿杂草的相对多度较高。说明土壤的盐度和湿度是影响河北省冬小麦田杂草群落组成的主要生态因子。 相似文献
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河北省玉米田杂草组成及群落特征 总被引：15，自引：2，他引：15
采用倒置“W”取样法对河北省玉米田杂草进行了调查,以明确田间杂草的种类组成及群落结构.结果表明,河北省玉米田杂草有136种（含变种）,隶属于34科、97属,其中优势杂草有马唐、反枝苋、稗、马齿苋、藜、狗尾草、铁苋菜、刺儿菜、田旋花等9种,区域性优势杂草有10种,常见杂草有21种,一般杂草有96种.发生优势度较大的杂草为马唐、反枝苋、稗、马齿苋、藜、狗尾草等,是构成各地区田间杂草群落的优势种.张家口地区主要形成反枝苋＋狗尾草＋灰绿藜＋藜为主的杂草群落,承德地区为马唐＋稗＋反枝苋＋藜,唐山-秦皇岛地区为马唐＋马齿苋＋鸭跖草＋稗＋反枝苋,石家庄地区为马唐＋牛筋草＋铁苋菜＋马齿苋.张家口和承德地区玉米田杂草群落的物种丰富度、多样性及均匀度较其它地区高,而优势度较低.从群落相似性来看,石家庄与唐山-秦皇岛地区群落结构最为相似.地理环境、气候条件及控草措施的不同,可能是导致玉米田杂草发生及群落组成产生差异的原因. 相似文献
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宁夏马铃薯田杂草种类及其群落特征 总被引：1，自引：0，他引：1
为明确宁夏马铃薯田杂草发生种类及其群落特征,采用倒置"W"9点取样法对宁夏马铃薯田杂草种类及其群落特征进行了研究,并进行了杂草物种多样性分析。结果表明:宁夏马铃薯田杂草有71种,隶属于22科56属,其中以菊科、禾本科、藜科为主,优势杂草为稗、灰绿藜、狗尾草和反枝苋。从杂草区域分布多样性分析来看,彭阳县物种丰富度最高,为39种,Shannon-Wiener指数为2.23、Pielou指数为0.61、Simpson指数为0.86。聚类分析结果表明,宁夏马铃薯田杂草群落可划分为3组,第1组为黄土高原丘陵沟壑及六盘山阴湿区杂草群落,第2组为盐、同、香山半荒漠区杂草群落,第3组为银川平原黄灌区杂草群落。综合分析,土壤结构和湿度是影响宁夏马铃薯田杂草群落组成的主要生态因子。 相似文献
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为了明确浙沪小麦田杂草发生情况及优势杂草控制技术,采用唐氏五级目测法和随机取样计数法相结合的方法,对上海和浙江的116块冬小麦田杂草进行了抽样调查,同时采用盆栽试验和田间小区试验测定了7种除草剂对主要危害杂草的防效。结果表明,浙沪冬小麦田共调查到杂草43种,隶属于14科,其中菊科杂草种类最多,有10种,其次是禾本科杂草9种,再次是石竹科杂草5种。杂草群落组成以禾本科杂草为主,优势杂草为日本看麦娘Alopecurus japonicus Steud.、菵草Beckmannia syzigachne(Steud.) Fern.、棒头草Polypogon fugax Nees ex Steud.、硬草Sclerochloa dura(L.) Beauv.、早熟禾Poa annua L.、鹅肠菜Myosoton aquaticum(L.) Moench、救荒野豌豆Vicia sativa L.、猪殃殃Galium spurium L.和小藜Chenopodium ficifolium Smith。室内除草活性及田间药效试验结果表明,日本看麦娘可用15%炔草酯WP、5%唑啉草酯EC、30 g/L... 相似文献
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江苏省镇江市麦田杂草发生情况调查 总被引：1，自引：0，他引：1
为了摸清江苏省镇江市麦田杂草种类、分布状况、出草规律、草相变化、防除情况等,通过倒"W"形九点取样法对镇江市麦田杂草进行了调查。调查结果显示镇江市麦田杂草有29科99种,日本看麦娘、菵草、猪殃殃、看麦娘、稻槎菜、硬草、繁缕、大巢菜、荠菜、涩荠、野老鹳草、牛繁缕、早熟禾为该地区主要危害性杂草,其中菵草、日本看麦娘、猪殃殃为麦田杂草群落优势种。不同地形区域杂草种类和优势种不同。镇江市麦田杂草由20世纪90年代初以看麦娘、日本看麦娘和猪殃殃等为主演变为以菵草、日本看麦娘、猪殃殃为主,稻槎菜、硬草、繁缕等发生较重。出草高峰集中在小麦播后15 d左右,具体到镇江来说11月底至12月上旬为杂草发生高峰期。针对镇江本地杂草发生情况,制定了以土壤封闭和茎叶处理相结合的防控技术方案。 相似文献
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我国农田杂草治理技术的发展 总被引：36，自引：0，他引：36
我国稻、麦、玉米、大豆及棉花等主要农作物农田杂草有580种,属于危害重而又难于防除的有17种,受杂草危害较重的农田有3 580万hm2,年平均受草害减产12.3％～16.5％(加权平均)。自1980年以来,全国化学除草面积以年增200万hm2的速度扩大,农田化学除草面积从20世纪70年代早期不到100万hm2扩大到近年来6 000万hm2。本文概述了我国农田主要作物杂草的发生危害、化学除草剂应用现状及其综合防治进展,并提出今后杂草防除的设想与建议。 相似文献
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Weed species composition of maize fields in Germany is influenced by site and crop sequence 
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下载免费PDF全文 During the last decade, maize has become the crop with the second largest acreage in Germany. Therefore, agricultural advisors and the plant protection sector are interested in an overview of the weed species composition in maize fields, their determining factors and trends. From 2001 to 2009, a weed survey was conducted in 1460 maize fields throughout Germany. Data on crop management and soil characteristics were collected via farmer questionnaires. Principal component analysis and redundancy analysis were used to analyse patterns in weed species composition. The late spring and summer germinating species Chenopodium spp., Echinochloa crus‐galli and Solanum nigrum occurred with high densities and frequencies, but their occurrence was determined by different factors. Other frequent weed species were those that typically accompany autumn‐sown crops. The variation in species composition was significantly related to environmental factors (9.1% explained variance), particularly geographical latitude and precipitation, and management factors (4.7% explained variance), particularly crop sequence. The relative importance of these factors seems universal, when compared with surveys in other crops and regions. The factor ‘year’ was of minor importance (0.9% explained variance). Over the 9‐year period, no changes in weed species composition could be determined. The results suggest that despite the limited impact of crop management on weed species composition, farmers can use crop sequence to suppress individual species. The survey furthermore sets a baseline against which future changes can be measured in a landscape of rapidly changing agricultural land use. 相似文献
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Transgenic glyphosate-resistant (GR) soybean [Glycine max (L.) Merr.] has enabled highly effective and economical weed control. The concomitant increased application of glyphosate could lead to shifts in the soil microbial community. The objective of these experiments was to evaluate the effects of glyphosate on soil microbial community structure, function and activity. Field assessments on soil microbial communities were conducted on a silt loam soil near Stoneville, MS, USA. Surface soil was collected at time of planting, before initial glyphosate application and 14 days after two post-emergence glyphosate applications. Microbial community fatty acid methyl esters (FAMEs) were analyzed from these soil samples and soybean rhizospheres. Principal component analysis of the total FAME profile revealed no differentiation between field treatments, although the relative abundance of several individual fatty acids differed significantly. There was no significant herbicide effect in bulk soil or rhizosphere soils. Collectively, these findings indicate that glyphosate caused no meaningful whole microbial community shifts in this time period, even when applied at greater than label rates. Laboratory experiments, including up to threefold label rates of glyphosate, resulted in up to a 19% reduction in soil hydrolytic activity and small, brief (<7 days) changes in the soil microbial community. After incubation for 42 days, 32-37% of the applied glyphosate was mineralized when applied at threefold field rates, with about 9% forming bound residues. These results indicate that glyphosate has only small and transient effects on the soil microbial community, even when applied at greater than field rates. 相似文献
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GHORBANALI RASSAM NASSER LATIFI AFSHIN SOLTANI BEHNAM KAMKAR 《Weed Biology and Management》2011,11(2):83-90
The aim of this study was to assess the effects of crop management practices on the diversity, structure, and composition of weed communities. A total of 30 fields (15 fields each) in low‐input and conventional farming systems were surveyed in north‐eastern Iran. In the conventional cropping system, both mineral fertilizers and herbicides were applied, while in the low‐input cropping system, the fertilizer was mainly manure and herbicides were avoided. The results showed that the pool of species, species richness, number of unique species, and Shannon's diversity index were greater in the low‐input system than in the conventional system. Both cropping systems had more broad‐leaved species than grasses and more annual species than perennial species. All the multivariate methods of analysis that were applied revealed that the weed community composition was significantly different between the two management types. The low‐input cropping favored herbicide‐susceptible broad‐leaved weeds, legumes, and weeds with biodiversity value, whereas a high proportion of herbicide‐tolerant grasses was found in the conventional fields. The results suggest that low‐input cropping can sustain high weed diversity and abundance. 相似文献