广西城市草坪杂草的种群及发生调查

以南宁市为中心,对柳州、北海、桂林、玉林和贺州6个广西主要城市的各类草坪杂草种类及发生规律开展了调查研究。结果表明:广西城市草坪共有杂草21科83种,其中优势杂草种类有19种,菊科、禾本科的优势杂草种类最多,分别占优势种群总数的31.6％和26.3％。向阳地生境草坪主要杂草种类为酢酱草和马唐,背阳地生境草坪主要杂草种类为圆果雀稗和空心莲子草,阴潮地生境草坪主要杂草种类为空心莲子草和水沙草。春季草坪主要杂草科为酢酱科和菊科,夏季草坪主要杂草科为禾本科和酢酱科,秋季草坪主要杂草科为禾本科和莎草科,冬季草坪主要杂草科为石竹科和十字花科。     

Long-term management of Striga hermonthica: strategy evaluation with a spatio-temporal population model

The parasitic weed Striga hermonthica poses a serious threat to cereal production in sub-Saharan Africa. Striga hermonthica seedbanks are long-lived; therefore, long-term effects of control strategies on the seedbank only emerge after several years. We developed a spatially explicit, stochastic model to study the effectiveness of control strategies in preventing invasion of S. hermonthica into previously uninfested fields and in reducing established infestations. Spatial expansion of S. hermonthica and decrease in millet yield in a field was slower, on average, when stochasticity of attachment of seedlings to the host was included and compared to the deterministic model. The spatial patterns of emerged S. hermonthica plants 4–7 years after point inoculation (e.g. seeds in a dung patch) in the spatial-stochastic model resembled the distribution typically observed in farmers' fields. Sensitivity analysis showed that only three out of eight life cycle parameters were of minor importance for seedbank dynamics and millet yield. Weeding and intercropping millet with sesame or cowpea reduced the seedbank in the long term, but rotations of millet with trap crops did not. High seedbank replenishment during years of millet monoculture was not sufficiently offset by seedbank depletion in years of trap crop cultivation. Insight from simulations can be employed in a participatory learning context with farmers to have an impact on S. hermonthica control in practice.     

Allelopathic potential of Trifolium resupinatum L. (Persian clover) and Trifolium alexandrium L. (Berseem clover)

This experiment was conducted in order to determine if Persian clover ( Trifolium resupinatum ) and Berseem clover ( Trifolium alexandrium ) contained water-soluble and methanol-soluble constituents that could affect the seedling growth of four test species; namely, Amaranthus retroflexus , Convolvulus arvensis (field bindweed), Secale cereale , and Sinapis arvensis (wild mustard) . The above-ground tissues of the Persian and Berseem clover plants were collected during the vegetative growth stage and oven-dried. Three concentrations of aqueous and methanolic extracts were used at full-strength (33.3 g L⁻¹), half-strength (16.7 g L⁻¹), and quarter-strength (8.3 g L⁻¹). Distilled water was used as the control. The weed seeds were placed in Petri dishes containing the legume extract or distilled water (control). The seedling growth of the weed species declined with the increasing concentration of the clover extracts. Wild mustard exhibited the highest sensitivity to both the legume extracts. Compared to the aqueous extract, the methanolic extract caused a greater decline in the seedling growth of the weeds. Berseem clover was the stronger inhibitor of the weed seedling growth, as compared to Persian clover. Therefore, the amounts of allelochemicals present might differ in these two clover species. Field bindweed showed the least sensitivity to both the legume extracts. Field bindweed showed more tolerance to the allelochemicals produced by the clover species.     

Cover crops and mulches influence weed management and weed flora composition in strip‐tilled tomato (Solanum lycopersicum)

This study was conducted in the Mediterranean environment of Central Italy from 2011 to 2013 with the aim of evaluating the effects of winter cover crops and their residues on weed composition in a cover crop‐tomato sequence. Treatments consisted of five soil managements (three cover crop species ‐ hairy vetch, phacelia, white mustard, winter fallow mulched with barley straw before tomato transplanting and conventionally tilled soil), two nitrogen fertilisation levels (0 and 100 kg N ha^?1) and two weed management levels (weed free and weedy) on tomato. Cover crop residues were arranged in strips on the soil surface and then used as beds for transplanting the tomato seedlings in paired rows. Rotary hoeing was performed in the bare strips between paired tomato rows. At tomato harvesting, the weed aboveground biomass and density was higher in nitrogen‐fertilised tomato than unfertilised tomato, except in hairy vetch and barley straw that showed similar values. Hairy vetch used as a cover crop and dead mulch was the most suppressive species with the highest production of residues, while phacelia and mustard were not suitable for controlling weeds. The tomato yield was high in nitrogen fertilised and weed‐free treatments, except in barley straw mulch, which showed similar values among the weed management treatments. The mulch strips caused variations in weed species composition that was mainly composed of perennial ruderal weeds, while in tilled soil, the weed flora was dominated by annual photoblastic weeds.     

山东省德州市棉田杂草种类及其发生规律研究

为明确山东省德州市棉田杂草发生、危害状况,于2013年对德州地区棉田杂草种类、出土规律及其群落自然消长动态进行了调查。结果表明：山东省德州市棉田杂草有19种,隶属于13个科,其中禾本科杂草的发生种类最多,而牛筋草、鳢肠和马唐的发生数量最为显著;田间共有3个杂草出土高峰,分别集中在5月中旬、6月底和8月中旬,前两个出土高峰中杂草的出土量较大;自然混生杂草群落内的总杂草数量在6月底达到峰值且在棉花整个生长季节内呈单峰变化。     

山东省花生田杂草的发生及其化学防除

本文概括介绍了有关花生田中杂草的发生种类、危害规律等方面的一些主要研究结果 ,简短回顾了山东省花生田化学除草的发展历程及现状 ,指出了目前花生田化学除草存的问题及对策     

Diversity and assembly of weed communities: contrasting responses across cropping systems

Diversity and weed community composition of mid-season plant stands and autumn seedbanks were examined in spring barley–red clover cropping systems that varied according to crop rotation, tillage and weed management. Weed plant and seed density data collected over 4 years were used in the calculation of species richness (number of species), evenness (Shannon's E) and diversity (Shannon's H′), and in multivariate analysis (canonical discriminant analysis) of weed communities. Weed diversity indices were low (H′ < 2.0) but sensitive to management practices. Evenness had intermediate values (E = 0.4–0.8), suggesting little evidence of truly dominant species, particularly in the seedbanks. The difference in the number of species between treatments was never large (approximately two to four species). Overall, diversity indices were highest in the low disturbance treatments, particularly those with minimum weed management. Factors affecting ordination were somewhat different from those affecting diversity. Tillage had little effect on weed diversity indices but had a more major role in determining weed community composition. Seedbanks in no-till and monoculture-chisel plough treatments appeared to have more distinctive species composition compared with other treatments. Weed species assembly in seedbanks showed little discrimination across treatments and over time, confirming the ability of seedbanks to buffer disturbances across a variety of cropping systems. The use of diversity indices revealed part of the complexity of weed communities associated with disturbance in cropping systems, whereas ordination singled out species–cropping systems associations, which may be more meaningful to weed management.     

Reviewing change in the arable flora of Europe: a meta‐analysis

Changing agricultural practices have dramatically altered the arable flora of Europe since the Second World War. We conducted a meta‐analysis of the available literature to assess the dynamics of species richness and species traits in the arable flora across Europe during this time period. We found a total of 32 publications, yielding 53 data sets with an average number of 252 studied plots per data set. Average species number per plot of arable plants across all data sets declined by about 20%. However, twelve data sets showed an increase in average species number per plot, including all studies starting after 1980. Plant species preferring nutrient‐rich sites, neophytes and monocotyledons generally increased since 1980, while characteristic or threatened species of arable weed communities further declined. This temporal development of the European arable flora suggests that the changes happening in agricultural management since the 1980s, such as organic farming and reduced pesticide input, may have helped slow the decline of the arable flora in terms of species number, but not in terms of characteristic or threatened arable weeds. Hence, more specific measures are necessary to stop decline of the latter, making sure that these measures are advantageous for rare and characteristic arable species, but not for harmful weeds.     

The more we do,the less we gain? Balancing effort and efficacy in managing the Solidago gigantea invasion

Developing invasive plant management strategies is an important task in modern ecology, conservation biology and land management. Solidago gigantea is considered a problematic invader in Europe and Asia, where it forms dominant stands that can decrease species diversity. There is, therefore, an urgent need for effective management to reduce S. gigantea infestations and their negative impacts. We examined the efficacy of multiple approaches to S. gigantea management in Hungary. In our study, we evaluated the effect of several long-term management techniques such as grazing, mowing and periodic flooding on the invader's density as well as native community diversity. In addition, we investigated the short- and long-term effects of mowing combined with other treatment options, to estimate the influence of increased management intensity. Our results indicate that all tested management techniques had negative impacts on S. gigantea density. Short-term mowing did not appear to improve species diversity in the resident community; however, all long-term options improved species diversity. Moreover, combining treatments with mowing varied in its effectiveness; mowing once increased the efficacy of flooding, but decreased the efficacy of grazing, while mowing twice decreased efficacy of flooding. We suspect this is due to the increased intensity of disturbance, which does not allow for the natural recovery of communities, and after management ceases, invasion is able to re-occur. Our results indicate that for effective management, we need to combine management options which act via different mechanisms, leading to cumulative positive effects on the resident community when applied at moderate levels.     

扬州市麦田草相特点及杂草防除对策

为了摸清扬州地区麦田杂草种类、分布状况,通过倒“W”形九点取样法调查,结果表明麦田杂草有26科81种,其中里下河地区优势种为日本看麦娘、牛繁缕、菵草等;沿江地区优势种为菵草、日本看麦娘、牛繁缕等;丘陵山区优势种为日本看麦娘、猪秧秧、野老鹳等;同时发现当前存在着杂草抗药性增强、防治技术不到位等方面问题,提出了强抓土壤封闭处理、合理选用除草剂及开展技术宣传培训等对策。     

Co‐operative versus non‐co‐operative farmers' weed control decisions in an agricultural landscape

This study presents a simple landscape model of the influence of seed dispersal on weed population dynamics between fields. In the model, three fields are interconnected through weed seed dispersal, where seed might move with field equipment, in irrigation water or may be wind‐dispersed. The model is intended to characterise the impact of field‐level weed management decisions on landscape‐level weed population dynamics. Two simple scenarios were studied. The first simulates farmers adopting common effective methods of control on each of the three fields. In the second scenario, farmers manage the weed population independently on each of the three fields. In the first scenario, weed populations were driven to extinction as might be expected with uniformly high levels of weed suppression in each of the three fields. In the second scenario, when the two nearest fields in the sequence experienced control, the weed population was driven to extinction in the second field but not in the first where weed populations were able to survive in spite of high levels of suppression. The results suggest that control measures within a field may not adequately reflect their impact on weed population dynamics when between field seed movement occurs. Another important result is the importance of proximity and spatial arrangement of fields and the resulting influence on weed population dynamics within a field.     

Maize–soybean intercropping effect on yield productivity,weed control and diversity in northern Ghana

The cereal–legume cropping system is a common practice across the tropical world. However, there are limited quantitative data on the effect of cereal–legume intercropping on weed species diversity. A study was conducted in the Guinea savanna zone of Ghana to evaluate the effect of maize–soybean intercropping on yield productivity and weed species control. The treatments used include three maize maturity types (extra‐early: Abontem, early: Sammaz 27 and medium: Obatanpa) intercropped with soybean at three intraspacing (10, 20 and 30 cm), and their sole crop treatments were laid in a randomized complete block design with three replications. Results showed that the land equivalent ratio (LER) for the intercrops was above 1, indicating better intercrop productivity than the sole crops. An average of 40% land was saved for the intercrops compared with the sole crops. Intercropping Sammaz 27 maize with soybean significantly increased LER by 9% compared to the other types. Intercropping maize with soybean significantly reduced weed biomass at 6 and 9 weeks after planting (WAP) and at harvest relative to the sole maize. The weed biomass at 6 and 9 WAP and harvest increased (p < .05) with increasing soybean intraspacing. The grass and broadleaf weed species count at 6 WAP and harvest from the sole crops were significantly higher than that of the intercrops. The results suggest that intercropping early maize maturity type with soybean at 10 cm intraspacing could be used to increase grain yield, LER and control of grass and broadleaf weeds in a maize‐based cropping system in the Guinea savanna zones of West Africa.     

山东省棉田杂草种类及其群落结构

为明确山东省棉田杂草发生、危害情况,采用倒置“W”取样法对山东省主要棉区杂草种类及其群落结构进行了调查,并进行物种多样性分析。结果表明：山东省棉田杂草68种,隶属于24科、49属,其中优势杂草4种,区域优势杂草10种,常见杂草17种,一般杂草37种。牛筋草Eleusine indica、马齿苋Portulaca oleracea、马唐Digitaria sanguinalis、铁苋菜Acalypha australis是构成不同棉区杂草群落的优势杂草。鲁西南棉区物种丰富度、多样性均高于其它棉区,但辛普森指数和均匀度指数低于鲁西北棉区。从相似性指数和聚类分析结果可以看出,山东省4个主要棉区可归为两大类,其中鲁北和鲁东北棉区的杂草群落结构最为相似,相似性指数高达0.833;鲁西南和鲁西北棉区归为另一类,相似性指数仅为0.637。     

宁夏马铃薯田杂草种类及其群落特征

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。     

Influence of obligate parasite Cuscuta campestris on the community of its host Mikania micrantha

As a means of biologically controlling Mikania micrantha in South China, the influence of the native obligate parasite Cuscuta campestris on its natural community was studied in the field. Mikania micrantha is a non‐indigenous vine that smothers other vegetation and has become a major invader of agricultural land and native areas in Southern China. These preliminary results showed pronounced effects on M. micrantha by C. campestris. Cuscuta campestris significantly reduced biomass of M. micrantha, increased species diversity and helped re‐establishment of native species. Biomass of M. micrantha decreased from 328 g m^?2 to 82 g m^?2, biomass of companion species increased from 41 g m^?2 to 145 g m^?2, the total number of species increased from 7 to 19 and the species diversity index from 1.8 to 5.6, when C. campestris was present. These results indicated that the use of C. campestris could be a potentially effective way of controlling M. micrantha and could help us achieve the novel objective of biological control of weeds using weeds.     

不同轮作制度对定西地区农田杂草群落的影响

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。     

灯盏花大田杂草种类调查及防除

经过4年对灯盏花田杂草种类的调查确定,在云南玉溪地区灯盏花田常见杂草有32种,隶属16科,主要杂草是鹅肠菜、野燕麦、长芒棒头草、无芒稗、酸模叶蓼,6月下旬至7月初为发生第1高峰期,10月中至11月下旬为发生第2高峰期,可通过药剂土壤处理、药剂茎叶喷雾防治和人工拔除控制灯盏花田杂草。     

云南省保山市烤烟地杂草种类与化学防除

调查了保山市烤烟地杂草分属35个科,计136种。本文记录了各种杂草的生活周期、生态特性;研究了砜嘧磺隆(rimsulfuron)、异丙甲草胺(metolachlor)、乙氧氟草醚(oxyfluorfen)、敌草胺(napropamide)、丁草胺(buta-chlor)、仲丁灵(butralin)、草甘膦(glyphosate)、五氟磺草胺(penoxsulam)、仲灵·异噁松(clomazone·Butralin)、苄·乙(bensulfuron-methyl,acetochlor)等10余种除草剂的使用技术关键,并成功地将砜嘧磺隆、异丙甲草胺等应用于烤烟地化学除草,累计推广面积4.6147万hm2,平均除草效果达80%～90%。