Enhanced Species Diversity Unlocked by Habitat Conservation in Agricultural Landscapes: New Perspectives on Ecological Weed Management and Sustainable Intensification—Species Diversity and Habitat Conservation

The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.

A Proposed Method for Evaluating Management Feasibility When Determining Weed Control Priorities after Major Fires and Floods

Major fires and floods have enormous impacts on natural ecosystems and are predicted to increase in frequency with global warming.Land managers need to make decisions on the prioritisation of weeds for control in post-disturbance landscapes,but little is available in the way of guidance to support timely decision making.Semi-quantitative models(e.g.,scoring systems)have been employed routinely in weed risk assessment,which considers the potential impacts posed by weeds,as well as the likelihood of these impacts being realised.Some progress has been made in the development of similar models addressing the topic of weed risk management.Under conditions prevailing after major disturbances,changes(both positive and negative)can be expected in the multiple factors that determine weed management feasibility,relative to pre-disturbance conditions.A semi-quantitative model is proposed that is based on the key factors that contribute to weed management feasibility in post-disturbance environments,along with annotated modules that could be used by land managers in both post-fire and post-flood situations.The fundamental challenge for weed management in these scenarios lies in the identification of differences between weeds and native species in relation to(1)patterns of seedling emergence;and(2)detectability relative to the growth stage.These two factors will determine the timing of control actions that are designed to address the trade-off between weed control and off-target damage during the period when both types of plants are recovering from a major disturbance event.The model is intuitively sound,but field testing is required to determine both its practical value and any necessary improvement.

Effects of Tinospora tuberculata leaf methanol extract on seedling growth of rice and associated weed species in hydroponic culture

The study was conducted to evaluate the responses of rice and rice weed seedlings （barnyardgrass and weedy rice） at the three-leaf stage toTinospora tuberculata leaf methanol extract （3.12, 6.25 and 12.5 g L–1） under hydroponic culture. It shows that the leaf methanol extract had various degrees effects depending on target plant species and each tested index （biomass, root length, shoot length, transpiration volume, chlorophyla, chlorophylb and carotenoid contents）. The effec-tive concentration of the leaf extract capable of reducing 50% of rice growth was higher than those of target weed species. Moreover, the root length was more tolerant to leaf methanol extract in comparison to the other plant parameters measured. A greater reduction was observed in chlorophyla content compared to chlorophylb and carotenoid. The results revealed that the reduction of transpiration volume closely coincided with the magnitude of growth inhibition of tested plants. Ultra-fast liquid chromatography analysis revealed 11 of 32 peaks in chemical proifle, including benzoic acid, caffeic acid, chlorogenic acid, isoorientin, isovitexin, orientin,p-anisic acid, syringic acid,trans-cinnamic acid,trans-ferulic acid, and vitexin have the same retention time with those peaks of the extract. The amount of compounds was present in the range of between 4817 and 115.5 mg kg–1 dry weight （DW）. The concentration-response bioassay of al 11 individual compounds and their equimolar mixture against the seeds of barnyardgrass revealed their contribution in the alelopahic activity ofT. tuberculata leaf extract. The examined compounds and their combination exhibited various degrees of growth inhibitory effects on the early growth of barnyardgrass. Therefore, the speciifc number, concentration, combination and inhibitory activity of bioactive compounds leads to alelopathy activity ofT. tuberculata leaves which could be employable directly as a natural herbicide and its growth inhibitor compounds can be used as a template for producing new herbicides.

Allelopathy of Medicinal Plants: Current Status and Future Prospects in Weed Management

An attempt has been made in this article to accumulate and elucidate the literatures about the allelopathic potentiality of medicinal plants, and its role on the development of bio-herbicides for eco-friendly weed management strategies to conserve bio-diversity and ecological balance. This review paper has been prepared by comprehensive studies of various published research articles, books and proceedings available in the world literature. The farmers of different countries use several weed management techniques in order to minimize the deleterious effect of weeds. Among them most commonly used practice is application of herbicides due to its high efficacy and cost effectiveness, less time-consuming nature, flexibility and easy accessibility, and more rapid out return. Although use of synthetic herbicides in the crop fields has increased the crop production as well as the productivity by reducing the weed infestation, over time it causes a number of environmental hazards. Hence, to avoid these detrimental effects of synthetic herbicide, a lot of efforts have been dedicated by the researchers to search the novel natural plant products mainly allelochemicals and try to apply them as a tool for the development of bio-degradable natural herbicides. This paper intended to reflect the current state of allelopathic medicinal plants and their potentiality to develop eco-friendly and natural product-based herbicides for sustainable agriculture, and to invite further debate on this issue.

不同土壤管理方式对北冰红葡萄生长及土壤理化指标的影响研究

为明确冰葡萄园土壤管理的最佳技术方法,本研究以生产上主栽的山欧杂交葡萄品种‘北冰红’为研究对象,以清耕除草为对照,园艺地布覆盖和自然生草为2种处理方式,研究清耕除草、园艺地布覆盖和自然生草3种土壤管理方式对冰葡萄园土壤性状及葡萄果实品质的影响。结果表明,园艺地布覆盖处理和自然生草处理的土壤容积含水量略高于清耕除草处理;7月下旬至8月中旬,园艺地布覆盖处理的土壤温度高于清耕除草处理和自然生草处理,高出0.02~0.22℃,8月下旬,自然生草处理的土壤温度高出清耕除草和园艺地布覆盖处理0.09~0.14℃;园艺地布覆盖处理的葡萄单株重、单穗重、可溶性糖含量、单宁含量都显著高于自然生草处理;自然生草处理的成本比园艺地布覆盖处理和清耕除草处理的成本分别低1425元hm^(2)和3075元/hm^(2)。吉林省冰葡萄园土壤管理的最佳方式是自然生草。

杂草管理方式对李园及其邻近天然林土壤真菌生态功能的影响

【目的】探索李园杂草管理对土壤真菌多样性的影响,为土壤健康管理提供参考。【方法】以贵州省安顺市紫云县自然生草、人工生草、除草剂除草李园及邻近天然槲栎次生林的土壤为研究对象,提取土壤真菌DNA,对其ITS基因进行扩增和高通量测序,分析真菌种类的构成、相对丰度、多样性、生态功能类别等。【结果】不同杂草管理李园和天然林土壤的可操作分类单元(OTU)在420~1039个,真菌种类共计14门、51纲、127目、260科、492属,天然槲栎次生林土壤的OTU数量不到李园土壤的一半。4个处理土壤均主要以担子菌门(Basidiomycota)和子囊菌门(Ascomycota)为主;与天然林相比,李园土壤的担子菌门减少,子囊菌门增加,其中人工生草李园土壤的变化幅度较小、分别为36.79%和32.85%。天然林土壤的红菇属(Russula)占据绝对优势,相对丰度达54.44%。李园不同类型土壤的第一优势属为沙蜥属(Saitozyma),相对丰度为14.54%~38.11%,其中人工生草李园优势较为明显。此外,人工生草李园土壤中梳霉门(Kickxellomycota)和球囊菌门(Glomeromycota)的相对丰度较其他类型高。多样性分析结果显示,天然林与其他李园土壤间α多样性差异极显著(P<0.01,下同);不同杂草管理方式中,人工生草与自然生草的Simpson指数差异极显著。FUNGuild分析显示,天然林土壤以外生菌根真菌占绝对优势,而李园土壤以腐生真菌和未知真菌为主。【结论】李园人工生草(光叶紫花苕)有利于优势属沙蜥属及低丰度的梳霉门和球囊菌门菌群建立。不同杂草管理方式的李园仅有少量丛枝菌根真菌(球囊菌门),缺少占绝对优势的有益真菌,有益真菌在李树的运用上还有较大的提升空间。优势种类的结构导致不同处理真菌群在生态功能上存在差异。

合成生物学助力链霉菌天然产物农药创制与产业化

病虫草害防控是国家总体安全建设的重要组成部分。微生物天然产物农药是病虫草害绿色防控体系的重要成员,在保障国家粮食安全、生态安全和农产品质量安全,筑牢国家生物安全屏障中具有重要作用。链霉菌以能够产生丰富的次级代谢产物而著称,是天然产物农药的资源宝库,也是重要的天然产物药物的工业生产菌。然而,随着病虫草害抗药性增强,新发、突发病虫草害增多等问题不断涌现,以及天然产物研究面临新骨架、高活性化合物发现难度增大,工业菌株产量提升困难等瓶颈,链霉菌天然产物农药创制与应用正面临巨大挑战。合成生物学作为一门交叉学科,突破了生物学研究的传统模式,为天然产物药物研发提供了新的思路与策略。本文综述了近年来合成生物学在链霉菌研究领域的技术革新,以及合成生物学在推动链霉菌天然产物资源发现、天然产物高效生物制造等方面的研究进展,并对合成生物学助力链霉菌天然产物农药的创制与产业化进行了展望。

Review on studies of Eupatorium adenophorum--an important invasive species in China

Eupatorium adenophorum Spreng. was introduced in Yunnan Province of China around 1940. Since then it has been spreading rapidly, particularly in the southern and southwestern parts of China and caused serious economic loss. The biological research and inte-grated control on E. adenophorum were carried out from 1980's in Yunnan Province. Together with other 15 invasive external species, the weed has been listed in the White Paper by The State Environmental Protection Administration of China. This paper briefly reviews the studies on natural distribution, biological character, ecological character, chemical component, hazard, potential application and the control of E. adenophorum. The research direction for this invasive external species in future was also discussed.

新疆天然草地毒草灾害分布与防控对策

新疆天然草地是少数民族地区畜牧业发展的物质基础,也是维持新疆自然生态坏境的重要组成部分。但长期以来,由于草地干旱、严重超载放牧、盲目开垦、人口增长等自然和人为因素的影响,以及草地基础设施建设投入不足和管理滞后,草地逆向演替,使得优良牧草逐年减少,毒草趁机大量繁衍滋生,造成草地大面积沙化和毒草化,致使大量家畜每年因误食毒草而中毒,甚至死亡。特别是近几十年来,草地毒草的迅速蔓延,造成草地植被群落和生物多样性减少,植被单一化,可食牧草急剧减少、草产量下降,草地退化和毒草化程度加剧。严重制约了草地畜牧业经济的持续发展,部分牧区天然草地毒草化已导致毒害草灾害多发、频发,甚至爆发,已经从基本的生态学问题上升为一个社会问题。新疆是中国主要牧区之一,天然草地总面积5 725.88万hm2,可利用草地面积4 800.68万hm2,位居全国第三。目前85.0%可利用天然草地出现不同程度的退化,37.50%草地严重退化,毒草发生面积接近700万hm2,约占全国天然草地毒草危害面积的20.42%,年平均牲畜毒草中毒死亡数超过3 000余头(只)。新疆天然草地常见有毒植物有81种分属24科54属,对草地畜牧业造成严重危害的主要有白喉乌头、准噶尔乌头、醉马芨芨草、小花棘豆、变异黄芪、无叶假木贼、马先蒿、橐吾和毒芹,约占毒草危害总面积的80%以上。因此,全面了解新疆天然草地毒草灾害状况、毒草种类与地理分布,对有效防控和化解毒草危害,提高草地生产力和牧草品质,促进牧区畜牧业的可持续发展和农牧民增收,繁荣边疆少数民族经济,维护生态环境平衡具有重要意义。本文在对已报道文献资料分析、归纳的基础上,结合课题组对新疆天然草地毒草实际调查情况,分别就近年来新疆天然草地毒草对区域草地生态及畜牧业生产造成的灾害状况、毒草种类与地理分布、毒草防控对策及合理利用进行综述。在此基础上,结合课题组多年来致力于中国西部毒草防控研究现状,分析了新疆天然草地目前存在毒草种类繁多、灾害严重、防治困难等问题及原因,提出应从生态角度出发,转变传统防除观念,科学认识毒草,立足"变害为利,变废为宝",生态保护与开发利用并重的思路,学习借鉴美国等发达国家在有毒植物预防控制技术方面的成功经验,以生态控制为主多种手段相结合的综合防控技术预防毒草灾害发生,以期为人们充分认识毒草在天然草地中的生态作用以及有效防控毒草灾害提供基础资料。

甘肃天然草地毒草危害、防控与综合利用

甘肃拥有天然草地1564.83万hm^2,位列全国第6位。长期以来,由于受干旱、鼠虫害和超载放牧等因素影响,天然草地退化严重,并伴随大量毒草滋生和蔓延,导致大批牲畜中毒,给畜牧业带来严重经济损失。甘肃天然草地常见毒草有78科187属312种,主要毒草有:瑞香狼毒(Stellera chamaejasme)、甘肃棘豆(Oxytropis kansuensis)、黄花棘豆(O.ochrocephala)、小花棘豆(O.glabra)、变异黄芪(Astragalus variabilis)、醉马芨芨草(Achnatherum inebrians)、橐吾(Ligularia sibirica)、苦豆子(Sophora alopecuroides)、马先蒿(Pedicularis resupinata)及栎属(Quercus L.)植物等。本文结合课题组对甘肃天然草地毒草资料整理及实际调查分析,分别就近年来甘肃天然草地毒草对区域草地生态及畜牧业生产造成的毒草灾害、地理分布、毒草种类、防控对策及合理利用进行综述。

泽兰实蝇寄生状况及其对紫茎泽兰生长与生殖的影响

泽兰实蝇（Procecidochares utilis）作为天敌控制紫茎泽兰（Eupatorium adenophorum）已经在国内外得到广泛的应用，但关于它对紫茎泽兰控制的有效性和防治现状的研究尚不深人。该文通过对攀西地区紫茎泽兰人侵危害严重的路域生态系统中泽兰实蝇寄生状况的抽样调查，初步研究了泽兰实蝇对紫茎泽兰生长，特别是生殖能力的影响。寄生率的调查采用随机取样法，分别从植株寄生率和枝条寄生率两方面进行，并比较不同生境下及不同年龄植株枝条寄生率的差异；选取相同数量、相同部位的各年龄植株寄生和非寄生枝条（对照），分别调查其花枝量、头状花序数及结实量，进行分析比较。研究结果表明：1）植株寄生率与枝条寄生率有显著差异（p〈0．05），分别为71、67％和17．30％，前者显著高于后者；样方调查结果，成熟群落中枝条寄生率为17．48枝·m^-2；1虫瘿·枝条^-1的枝条占所有寄生枝条的92．30％；2）湿润生境下紫茎泽兰的枝条寄生率为20．27％，显著高于于旱生境下的枝条寄生率（9．33％）（P〈0．05）；3）不同年龄植株枝条寄生率有差异，0～1年生植株枝条寄生率分别为36．36％和21．56％。显著高于2-4年生的植株枝条寄生率，分别为13．50％、8．82％和12．16％（P〈0．05）；4）在目前的寄生强度下，泽兰实蝇对紫茎泽兰枝条的直径、花枝量、头状花序数及结实量均无显著影响（P〉0．05）。

上海地区进口花卉的逸生性调查和研究

上海地区已有 10种进口花卉逸生为杂草 ,隶属于 4科。其中 ,部分危害程度已相当严重 ,而且其中的一些种仍在被作为优良花卉引进。引进花卉在我国逸生为有害杂草 ,与花卉的某些生物学特性和对环境的适应能力及环境阻力因素有关 。

中国天然草地毒草灾害分布与防控技术的研究进展

草地是畜牧业发展的物质基础,也是维持自然生态平衡的重要成分。长期以来,因草地干旱、严重过载放牧、滥垦等人为和自然因素影响,使得优良牧草逐年减少。毒草趁机大量滋生繁衍,草地逆向演替,造成草地毒草化,草地生态环境遭受严重破坏,且每年引起大量家畜误食毒草中毒,甚至死亡。特别是近十几年来,草地毒草的快速蔓延,造成草地可食牧草急剧减少、草地不同程度退化和毒草化,严重制约草地畜牧业经济的持续发展,给草地生态环境平衡及牧区社会稳定发展带来不利影响。通过对已报道文献资料分析与归纳,分别对中国天然草地毒草种类、灾害状况、地理分布、毒草防控技术进行综述,并进行了展望。

我国天然草地毒害草化学防控研究进展

我国拥有天然草地面积3.93亿hm2,位居世界第二。天然草地是我国重要的绿色生态屏障,具有调节气候、防风固沙、保持水土、涵养水源、固氮储碳、净化空气、维护生物多样性等重要功能,也是发展草地畜牧业的重要物质基础。长期以来,由于天然草地干旱、鼠虫害、超载过牧等因素的影响,导致草地严重退化、沙化、生态持续恶化,可食牧草急剧减少,而毒害草却大量滋生和蔓延。毒害草导致牲畜中毒呈现多发、频发,甚至暴发态势,经济损失严重,被称为天然草地的"绿色杀手"。对我国西部地区牧民的生产、生活、社会稳定和国家生态安全造成威胁。论文围绕毒害草对草地畜牧业的危害、除草剂发展历程、除草剂种类、除草剂在防控主要毒害草方面的应用等方面进行综述,并提出今后毒害草防控中应注意的问题,对科学认识毒害草在天然草地中的生态作用和综合利用有指导意义。

不同生境小花山桃草自然种群表型变异与协变

小花山桃草自然种群的表型特征是其对自然生境适应的结果,不同生境种群间表型特征的比较可为揭示其表型变异产生的原因及变异规律提供重要线索。本研究以分布于不同生境的5个小花山桃草自然种群为研究对象,研究了16个表型性状的变化特点。研究结果表明,小花山桃草表型多样性较为丰富,表型性状的平均变异系数为36.30%。表型分化系数在26.85%～96.98%之间,平均为73.03%,表明种群间变异是小花山桃草表型变异的主要来源。不同性状对环境变化的反应不同,其中株高、茎粗、单株果数和比叶面积在种群内的差异不显著,而在种群间的差异达到极显著水平,表型分化系数达82%以上;节间距、叶宽、主根长、分枝数、果长和果宽在种群间和种群内的差异均达极显著水平;单果种子数和单果重在种群内和种群间的差异均不显著。株高、茎粗、叶长、叶宽、茎重、叶重、主根重和单株果数表现出一致的协变格局,生理功能性状之间的这种整合特性有助于小花山桃草适应多样的生境。聚类分析显示,5个种群可按生境条件的好坏分为两大类,进一步表明小花山桃草的表型特征受种群间环境条件（水、肥）强烈影响。绝大多数表型性状与生境因子存在显著或极显著的相关关系,但果实性状（包括果宽、单果重和单果种子数）与生境因子相关性低,进一步表明繁殖性状不易受环境条件影响。

苹果园植被多样化在果树害虫持续治理中的作用

１９９２～１９９５年对四个不同类型苹果园进行了系统调查，结果表明引入夏至草、泥胡菜等有益杂草并与树行间种植的紫花苜蓿搭配的生草园，捕食性天敌发生量大，种群稳定，发生高峰期较免耕园、清耕园提前７ｄ左右；害虫发生量低，种群数量变化平稳，无突增现象，生草园在未施用任何杀虫、杀螨剂的情况下，树冠上蚜虫、叶螨和潜叶蛾的平均虫口密度均低于免耕园、清耕稀植园和密植园。生草园寄生性天敌的数量亦明显增加，金纹细蛾的寄生率高达６２７％，分别是免耕园、清耕稀植和密植园的１３４倍、１６９倍和１７９倍。果园植被多样化可使地面植被上的天敌数量逐年成倍提高，生草第３年捕食性天敌的数量是生草当年的１２５倍，树冠上天敌量亦明显增加，益害比大大提高，生草第２年树冠上最大蝽螨比为１∶１４４，与原先油菜与紫花苜蓿搭配生草５年的效果相近。除当年生草果园（１９９２年）早期施用１次杀螨剂螨克外，１９９３、１９９４年均未施用任何杀虫、杀螨剂，通过天敌的自然控制作用，有效地控制果树害螨、蚜虫和金纹细蛾等次生性害虫的为害。

天然除草活性化合物研究进展

综述了近年来国内外从天然产物中开发具有除草活性化合物的研究概况,着重介绍一些可能具有除草剂开发潜力的植物和微生物源化合物,并对生物除草剂的发展前景进行了展望。

新疆阿克苏地区天然草地毒草分布及危害状况调查

采用现场调查与资料收集相结合,对新疆阿克苏地区天然草地毒草种类和地理分布及危害等进行了调查。结果表明,阿克苏地区天然草地毒草分布面积62.05万hm2,占可利用草地面积7.12%,年平均牲畜毒草中毒数超过7 000余头(只)。天然草地主要毒草有66种,分属22科,49属,对畜牧业生产造成危害的主要有小花棘豆、苦豆子、苦马豆、骆驼蓬、黄花棘豆、无叶假木贼、盐角草、盐生草、醉马芨芨草、苍耳等。结合调查结果提出了毒草防控建议。

自然农法条件下稻田有益微生物菌群多年施用累积效果

在自然农法条件下,对稻田连续9年施用有益微生物群(EM)的累积栽培效果进行了研究。连续施用EM使土壤的养分状况发生了明显的改变,使水稻抽穗期推迟,花期延长,叶色加深。EM的应用还能有效地改善产量结构、提高产量,而且应用年限越长,效果越明显,并且有助于改善稻米品质、减少稻米中钾和镁的含量、增加直链淀粉含量和食味评价值,口感较好。EM的应用在一定程度上可以抑制杂草的发生和生长。

微生物及其天然产物防治杂草的发展及展望

概述了利用微生物及其天然产物防治杂草的潜在优势和研究进展,介绍已商品化和具有开发潜力的 微生物除草剂及具有除草活性的微生物天然植物毒素。