杂草学第三章.pdf

姜临建姜临建2013.10.232013.10.23Section 3Section 3Methods of Weed ControlMethods of Weed ControlTerminologyA.Eradication（根除）Complete kill or removal of a weed species from a defined geographical areaB.Weed Management(杂草治理)Limiting weed population to a level that will not cause economic damage.Weed Eradication（根除杂草）Ideal of weed control Very difficult and expensive.Why is it so hard to eradicate weeds?prolific seed production;long life of seed;numerous methods of weed dispersal;difficulty of avoiding reinfestation There are always Exceptions!总有例外Striga Story in US Striga attacks primarily grass species:corn,sorghum,sugar can,rice 1955 Striga was first find in corn field in NC 1957 Striga eradication program started 2002 total of$250 million spent Weed Management(杂草治理)Goal:low population of weeds that does not cause significant economic loss.Integrated Weed Management(IWM)Integrating all weed control methodsWeed Control MethodsA.Prevention(预防):To prevent introduction,establishment,and/or spread of a specified weed species into an area not currently infested with that species.A.Prevention1.Use of weed-free crop seed2.Clean equipment before moving from infested to non-infested fields;use caution when contracting for custom harvesting and other operations3.Avoid hay,livestock feed,manure,mulch,etc.containing seed of species currently not on farm4.Weed-free irrigation water5.Caution when purchasing used equipment6.Careful consideration of rented land7.Prevent introduced weeds from going to seed;including field bordersB.Mechanical Control 1.Hand pulling and hoeing 2.Tillage 3.Mowing 4.Mulching 5.Burning and heatHand pulling and hoeing Labor intensive.High value cropsCalifornia organic farmTillage/cultivationTillage/cultivation 控草原理：破坏植物根系，埋藏营养体，深埋种子 hot,dry soils when weeds are smallCertain herbicide requires cultivation.氟乐灵Cons（缺点）plant neighboring weedsmowing 控草原理：Tall-growing weeds;repeated mowing may prevent seed production 草坪控草的重要方式 more effective on broadleaf weeds than on grasses Weeds adopting to mowingyollow foxtail erect-prostrate Cons:Equipment,Repeat operation,LaborMulching(覆盖)控草原理：physically supress weed growth;light-induced seed dormancy;Releasing allelochemicals 覆盖物种类：秸秆，地膜，木屑等 一般与化学除草联用。新疆的棉花膜下滴灌；花生，玉米等 cons：high cost，waste removal,contain weed seedsMulching(覆盖)Burning and heat 杀草原理 热源种类：火焰，蒸汽，阳光 Examples:秸秆焚烧 棉花 20 cm tall with small weeds Organic weed control.Burning and heat cons：设备费用，安全性，操作性。火灾隐患，爆炸隐患。空气污染PM2.5How about coldness 干冰 液氮B.Mechanical Control 1.Hand pulling and hoeing 2.Tillage 3.Mowing 4.Mulching 5.Burning and heatC.Cultural Control（栽培）1.Crop Competition 2.Crop Rotation 3.Cover crops 4.Water managementCrop CompetitionCrop Competitionrow spacing传统种植模式高光效种植模式玉米种植模式Crop Rotation控草原理：1.Result in healthier crops that compete better with weeds.2.Given weeds tend to be associated with given crops(水旱轮作)3.Crop rotation has impacts on chemical control.（大豆和玉米轮作）Cover Cropswheat,rye,vetch,clover控草原理：1.生长快，快速形成冠层，遮光2.Mulching effects(physically and chemically)4.Water management a.Flooding used in rice production for weed control.（水稻，旱稻）b.渗灌 滴灌（新疆棉花）C.Cultural Control（栽培）1.Crop Competition 2.Crop Rotation 3.Cover crops 4.Water managementD.Biological Control Grazing animals 牛，羊，猪，鸡鸭鹅 果园除草优秀年轻人总结起来有5个特质：1.有好奇心；2.对不确定性保持乐观；3.不甘于平庸；4.不傲娇，能延迟满足感；5.对重要的选择有判断力。“科学技术是第一生产力”科学技术D.Biological Control Insects:moth/prickypearUse of a leaf-feeding beetle(Chrysolina quadrigemina)in the mid 1940s to control St.Johnswort in the western US.D.Biological Control Pathogensa.Classical approach:an initial inoculation of the weed with self-sustaining pathogenic fungiSkeletonweed in Australia by the fungal rust Curly dock 皱叶酸模 in Europe by fungal rust b.Mycoherbicide approach.A mycoherbicide is defined as a fungus used as a weed killer DeVine生物除草剂缺点 专一性强/杀草谱窄 起效慢 Shelf life 环境因素（病原-宿主-环境）作业因素E.Chemical Control:use of herbicides What is Herbicide？any chemical agent that kills or greatly inhibits plant growth.除草剂的专业术语 1.Active ingredient 2.Trade name 3.Common name 4.Chemical name 玉农乐 烟嘧磺隆 2-（4,6-二甲氧基嘧啶-2-嘧啶基氨基甲酰氨基磺酰）-N,N-二甲基烟酰胺除草剂的分类 A.Selective（选择性）vs.Non-selective1.Selective：Selectivley kill some weeds2.Non-selective:kills or severely damages all or most species.灭生性 B.Contact(触杀)vs.Systemic（系统性，传导性）Contact Herbicidesa.Effective only on tissue contacted by application of herbicideb.Very little movement(translocation)within the plantc.Coverage is essential d.Usually exhibit acute effectse.Effective for annuals,usually ineffective for perennials f.Can be selective or non-selective.Systemic Herbicides a.Absorbed by roots or shoots translocated within plant.b.Coverage is less essential than contact herbicides c.Usually exhibit chronic effects-slow acting.d.Effective on annuals,some are effective on perennials e.Can be selective or non-selectiveC.Residual vs.Non-ResidualNon-Residual:Herbicide has activity only on weeds present at time of application.C.Residual vs.Non-Residual Non-residual herbicide is also called foliar treated herbicide Residue herbicide-soil treated herbicideIV.Types of Herbicide Applications A.Early preplant(EPP):B.Preplant Foliar(PPF):C.Preplant Incorporated(PPI):D.Preemergence(PRE):E.Postemergence Overtop(POT):F.Postemergence-Directed(POST-DIR):A.Early preplant(EPP)Purpose:control winter annuals or early germinating summer annuals Mechanism:Residue activityB.Preplant Foliar(PPF):Often referred to as“burndown”application.免耕/“少耕”体系中的最广泛使用的除草方式 Primarily foliar non-selective herbicide.glyphosate(草甘膦)+2,4-D最为普遍C.Preplant Incorporated(PPI播前混土)Volatile;incorporation reduces volatility losses.Photodegradation;incorporation reduces these losses.Very low water solubilityD.Preemergence(PRE，苗前)杂草或作物出苗之前施用 To soil surface Need activation（激活除草剂）Activation means movement of the herbicide into the weed seed germination zone by rainfall or irrigation土壤墒情要高，或者使用后降雨或灌溉。Deep-germinating weeds may be less affected by PRE than PPI herbicidesE.Postemergence(POST 苗后)苗后茎叶处理 选择性除草剂，作物和杂草同时受药优点：不受土壤墒情影响缺点：1.喷施的窗口期（作物及杂草）2.环境因素：干旱影响除草效果；苞卫药害3.雨水冲刷F.Postemergence-Directed(POST-DIR)苗后定向喷雾 目的是除草剂接触杂草，不接触作物 一般为灭生性除草剂果园喷施非选择性除草剂玉米地中喷施百草枯等V.Area of Herbicide Application A.Broadcast:herbicide applied to all of the planted area B.Banded:herbicide applied to only part of planted area C.Spot treatment本节要点 杂草治理的概念 非化学除草的方式及其原理 除草剂的分类 除草剂的施用方法（按照施用时期）http:/