农业生态学(双语）_王松良等编著_9787030329998

　本书是国家双语教学示范课程的配套教材，也是“（中国）福建农林大学-（加拿大）新斯科舍农学院‘2+2’本科教学合作项目”的成果之一。本书紧紧围绕“农业是把太阳光转变成人们健康、幸福生活的科学、艺术、政治学和社会学”这一对“农业”的新理解，把“农业生态学”定义为农学与生态学联姻的学科和实现农业生态系统可持续管理的应用科学。主要介绍农业生态学的学科内涵、农业生态系统的基本过程及其人为问题、可持续农业生态系统的构建与管理等内容，并包括该课程系列实践教学指导书。
　　本书视角独特，图文并茂，适合于高等农林院校同名课程的双语教学用书，也可作为农业院校和科研院所研究生考试的参考书。

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Unit 1 Context of Agroecology

Chapter 1 Agriculture and its anthropocentric sciences

Learning objectives

1.Define the terms agriculture,ecology,ecosystems andagroecology.

2.Discuss how the science of agroecology fits in the realm ofnatural and so cial sciences.

3.Explain why corn is a good symbol for the study ofagroecology.

4.Compare and contrast the characteristics of natural andmanaged ecosys tems.

5.Explain how the concept of " Making money and respecting theenviron ment" is central to agroecology.

1.1 What are agriculture,ecology and agroecology?

"Agriculture is the science,art,politics and sociology ofchanging sunlight into healthy,happy people"

――C.D.Caldwell,1996

When we first learn the principles of ecology,we stand apartfrom the system;we are observers of nature-measuring,modelling andpredicting behaviour and out comes in various systems from puddleto biosphere.We see ourselves as unbiased,highly interestedobservers of the interactions within and between our biotic and abiotic environments.Thus,ecology has become defined as the scientificstudy,through observation and analysis,of the relationships betweenliving organisms with each oth er and their environment.

By comparison,agriculture seems to be a misunderstoodscience,tainted with the ideas that our endeavours are solelyselfserving.In fact,the Oxford Concise Dictionary dismissesagriculture as anything more than,the "science or practice ofcultivating the soil and rearing animals." This cursory definitiononly explores one facet of the complex scientific study andpractice of agriculture.

1.1.1 Definitions of agriculture

Let's refer to the definition of agriculture as the science andindustry of managing the growth of plants and animals for humanuse(Skanavis,2004).Traditionally,agriculture includes cultivationof the soil,growing and harvesting crops,breeding and raisinglivestock,dairying and forestry(Skanavis,2004).Agriculture sectorsusually consist of crop farming,animal husbandry,dairyfarming,forestry,poultry farming and soil management.

Over time,human use and interpretation of agriculture hasevolved.Agriculture played a key role in population settlement andthe rise of modern civilization.The hus bandry of domesticatedplants and animals allowed for these societal changes,crea tingfood surpluses that enabled more densely populated and stratifiedcommunities.

A general agronomic textbook defines agriculture as "theinfrastructure of nation al economy,and main source of living,aswell as industrial material for human be ings"(Zhai,1999).Thisdefinition regards agriculture as a source of food,clothing and financial income,focusing on agriculture as " moneybased" andeconomy driv en.Agricultural practices under these definingideologies have deteriorated natural resources and theenvironment(soil,water and atmosphere).This has become apparent bythe depletion of ecological diversity and productivity fromincreased agricultural production,in an effort to meet aneverincreasing demand for food by an overpopu lated society.Thedestroyed ecological diversity and productivity can no longersupport infrastructure and provide a base for all agroeconomicproductivity.The Industrial Revolution replaced many organicmaterials with synthetic materials in agriculturalecosystems(agroecosystems),which led to the formation of "ModernFossil Fuel Agriculture." This increased dependence on syntheticmaterials and fossil fuels in agricul ture has only exacerbated thedeterioration of agroecosystems.However,Agriculture is multifacetedand extremely important;it is not limited to food production andeconomic output,but rather,it is a critical interface betweenhumans and nature.

Ancient Chinese books,poems and paintings depicted an idealfarmingoriented society among a charming agroecologicalenvironment.The ecological functions of sound agriculture andforestry,as depicted in ancient Chinese art,are summarized asfollows(Wang,2005):

Water and soil conservation

Climate and rainfall regulation

Protection of land from wind and desertification

Landscape beautification and pollution prevention

Living energy supply and source of fertility

Fortunately,researchers and government agencies in the world aregradually rec ognizing the multifunctionality ofagriculture.Caldwell(1996)redefined agriculture as "Thescience,art,politics and sociology of changing sunlight intohealthy,happy people(农业是把太阳光转变成人们健康、幸福生活的科学、艺术、政治学和社会学)"(Wang,2005).

This expanded definition better recognizes the function ofagriculture;it means that agriculture is a natural ecologicalprocess,whereby solar radiation converts ener gy and matter fromnatural resources(including land,atmosphere and water)for food andhuman environment.This definition incorporates people as anessential com ponent,emphasizing the equilibrium point for humanbenefits and natural conserva tion,or "the basic interface betweenpeople and their environment"( Valentine,2005).One can group themajor agricultural products in the following categories:foods,fibers,fuels,raw materials,pharmaceuticals and stimulants,andan assortment of ornamental or exotic products.Ecological designsof agronomic and horticultural systems have become part of thefunctionality of agriculture.

The point to note here is that agriculture is homocentric.Aliteral interpretation of homocentric would put people at thecentre;a functional interpretation puts people as a beneficiary butnot central.

In addition to supporting industry and the economy,agriculturealso promotes land renovation,biodiversity,nature conservation anddesign.

(1)Agriculture is a driver of the global economy.

Supports the livelihoods and subsistence of people worldwide

(2)The agricultural sector must simultaneously.

Secure enough highquality agricultural production to meetdemand

Conserve biodiversity and manage natural resources

Improve human health and well being,especially for the ruralpoor in develo ping countries

Agricultural management must continually increase theproductivity of existing farmland to meet population demand throughthe adaptation of good and efficient management prac tices.Additionally,management should embrace the three pillars ofsustainability,repre senting natural(environmental),social andeconomic factors(Fig.1.1).

1.1.2 The science and discipline of agriculture

Science and technology are the building blocks of modernagriculture.One must understand the biological and physicalsciences underlying agricultural engineering andtechnology.Successful farming requires the knowledge oftillage,irrigation,fertiliza tion,drainage and sanitation.Someaspects of farming require further specialized knowledge,whichagricultural engineers can carry out.Agriculture encompasses a widevariety of specialties and techniques.One such specialty is theability to increase suitable land for plant production,usuallyperformed by digging waterchannels and other forms ofirrigation.Cultivating crops on arable land and pastoral herding oflive stock on rangeland are some of the fundamental practices ofagriculture.

In the past few decades,plant breeding,agriculturalchemistry(e.g.pesticides and fertilizers)and correspondingtechnological improvements have sharply increased yields fromcultivation(Tab.1.1).For instance,plant breeding and geneticscontrib ute immeasurably to farm productivity;meanwhile,geneticshave turned livestock breeding into a science.However,some of thistechnology causes widespread ecologi cal damage and negativelyimpacts human health.Hydroponics,a method of soilless gardening inwhich plants are grown in chemical nutrient solutions,may help meetthe need for greater food production as the world's populationincreases.Similarly,selective breeding and modern practices inanimal husbandry,such as intensive pig farming(and similarpractices applied to chickens),have increased the output ofmeat.However,hydroponics can lead to pathogen attacks and selectivebreeding in crop varieties has led to the utilization of only a fewplant species and monocropping,reducing biological diversity.Inaddition,concerns have increased about animal wel fare and humanhealth effects from antibiotics,growth hormones,and other chemicals often used in largescale meat production.

Agricultural chemistry which includes,but are not limited to:the application of fertilizer,insecticides and fungicides,soilmakeup,analysis of agricultural products and nutritional needs offarm animals,must take into account many crucial farmingconcerns.The increasing use of inorganic fertilizers and syntheticpesticides poses many problems in soil degradation,ground watercontamination,food safety,toxic ity accumulation in naturalwildlife and other environmental deterioration.

The packing,processing,and marketing of agricultural productshave also been influenced by science.Methods ofpreservation,quickfreezing and dehydration have increased marketsfor farm products and decreased postharvest losses.These processesdo,however,mean the use of more chemicals and materials potentiallyleading to resource depletion,food safety concerns and increasedenvironmental pollution.

Agricultural science has primarily focused on components of theproduction process,maximizing net returns on single products perunit of land or labour.All other resource use and environmentaleffects have been considered "externalities"(Fran cis etal.,2003).

Many problems resulting from modern agriculture occur because ofreductionist disciplines and utilitarian technologies.Thus,we needto modify our understanding of agriculture,integrating Caldwell'snewer definition(1996)with a new science and discipline toinvestigate agriculture in a more inclusiveway.Agroecology,therefore,should be considered a cutting edgediscipline that bridges ecology(including human ecology)withagriculture.

1.1.3 The link to the discipline of ecology

The etymology of ecology stems from the Greek words "oikos"(house or place to live in)and " logia"(study of).The wordecology was proposed and defined by Ger man biologist,ErnstHaeckel,in 1866.His definition states "Ecology is the science ofthe relations between organisms andenvironment"(Odum,1969;1983).This defini tion implies that ecologybuilds upon related biological sciences such as zoology andbotany;such disciplines usually examine organismsthemselves,whereas ecology explores the relationships betweenorganisms with each other and their environment.While ecology canbe considered a biological science,it spans a much broader studyarea,including earthscience,chemistry,physics,mathematics,medicine,and certain aspectsof the social and economical sciences.The famous ecologist,EugeneOdum,stated that Ecology is "a science bridging biology and socialscience"(Odum,1971).This explains ecology in terms of aninterdisciplinary science,mixing natural science with socialscience,where one can also infer a particular emphasis on economicsand politics.A holistic or integrated approach to the investigationof ecosys tems requires considerable knowledge,effort andscientific resources.The results of ecological studies are oftencontrary to what one may expect at a first glance.Fig.1.2Bioorganizational scales in ecology(Odum,1983).

Although the study of ecology traces back to ancient Greek andRoman times,modern ecolo gy was born from and accelerated by thesocial and environmental problems of the 18th century IndustrialRevolution.Modern ecology originated as a response to the globalemergence of the "FiveEcologicalCrises,"i.e.Population,Food,Resource,Energy and Environment,at the beginning of the 20th century.Essentially,ecology is the economics ofnature,as opposed to the moneybased economics that investigates theso cial economy.Economics focuses on accounting for ways to regroupresources to maximize the output,regardless of any abstract innatevalue.

Ecology investigates the interactions among organisms and theirenvironments at various scales,from individual organisms to apopulation,community,ecosystem or biosphere.Fig.1.2 illustrates thescales of ecology,classified under subjects such as molecularecology,autecology( species ecology),population ecology,communityecology and global ecology.

1.1.4 The link between agriculture and ecology: the inclusivediscipline of agroecology

The role of ecology in agriculture is to find the pivotalbalance among global food security,advantageousproduction,technological innovation,environmental preser vation andprotection of biodiversity( Ormerod,2003).Both agriculture andecology have common roots in the disciplines ofbotany,chemistry,physics and geology,with very distinctapplications and management practices(Paul,1989).Agroecologymanifested from these relationships,first emerging in the 1930s;itsinitial phase lasted until the 1960s,af ter which the scienceexpanded until it became considered a discipline in its own rightand in stitutionalized in the 1990s(Wezzel,2009).Prof.Luo Shiminget al(1987)defined Agro ecology as "a science of theinteraction,coevolution,regulation,control and equilibrium development between agroorganisms and their environment(both natural andsocial),based upon the principles of ecology and systematic theoryandpractice(农业生态学是应用生态学的原理、系统论的观点和方法,把农业生物与其自然和社会系统作为整体,研究它们之间的相互联系、协调演变、调节控制和平衡发展规律的科学)".Thisdefinition is inclusive and reflects the intent of Caldwell'sdefinition(1996)of agriculture.While agroecology is derived fromthe larger field of ecology,draws even more strongly on the socialsciences to construct understanding and predictions about organismrelationships.Ecology can be considered the "parent" theory ofagroecology because the goals of the discipline are to pursue thesustainable management of particularecosystems;i.e.agroecosystems.This is evi denced by the recenthistory of corn(maize,Zea mays)in agroecology.

1.1.5 The development of agroecology as a discipline andscience

(1)Agroecology developed under the background of the globalecological crises concerning agriculture

Agroecosystems play a crucial role in our lives because theyprovide us with food and fibre while greatly impacting the qualityof our environment( Elliott,1989).Historically,global ecologicalcrises concerning agriculture have been the inspiration for thedevelopment of agroecology,as well as a major source ofconflict.China represents one of the Ancient Farming Societies ofthe world.In China,nature has been destroyed mercilessly since thefirst hoe was used in agriculture,transforming the "GreenGrassland" into the " White Desert",and " Mother River" into the "Yellow River" .Globally,ecology has been involved in revolutionsboth of environmental protection and of environmental sciences.Soonafter Rachel Carson revealed the far reaching effects of chemicalpesticides used broadly in agricultural practice in her famous bookSilent Spring,many ecologists dedicated their careers toagroecosystem research.

(2)Agroecology promotes the evolution of the agriculturaleconomy from " In dustrialbased" to "Intelligencebased"

" Historical Agriculture" refers to the first 10,000 years ofagricultural develop ment.Prior to that,people lived by hunting andgathering.Historical Agriculture required extensive cultivation andproductivity relied entirely on the unpredictability of nature andweather.This economic pattern could be realistically defined as a"nature based economy." Subsequently,LabourIntensive Agriculturewas born 2000 years ago,the productivity of which depended totallyon people power and land character istics.This economic patterncould be described as a " subsistencebased economy."Theagricultural pattern has changed drastically from a "naturebasedeconomy" to an "industrialbased economy" since the IndustrialRevolution.Modern agriculture can be formularized by "fossilenergy+technology＝commodity," showing that fossil energy and moderntechnology have become the dominant factors for agriculture.Consequently,agricultural productivity has increased tremendously whencompared with the former two stages(Tab.1.1).As a negativeresult,however,such patterns have generally destroyed the naturalsustainable mechanisms of agriculture.

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