agriculture and the environment ocr a2 options environmental biology

Agriculture and Agriculture and the Environmentthe Environment

OCR A2 OptionsOCR A2 Options

Environmental BiologyEnvironmental Biology

Development of Farming Development of Farming in Britainin Britain

14, 000 y.a14, 000 y.a domestication of dogs from semi-wild animalsdomestication of dogs from semi-wild animals

9,000 – 10,000 y.a9,000 – 10,000 y.a domestication of cattle, sheep and goatsdomestication of cattle, sheep and goats gatherer-huntersgatherer-hunters

5,000 – 6,000 y.a 5,000 – 6,000 y.a Agriculture developsAgriculture develops lowland deforestation for crop growinglowland deforestation for crop growing

Deflected SuccessionsDeflected Successions Succession Succession

the gradual replacement of one plant the gradual replacement of one plant community by another over a period of time, community by another over a period of time, through a series of seral stages ending with a through a series of seral stages ending with a climax community.climax community.

Deflected succession Deflected succession the original path of succession is deflected by the original path of succession is deflected by

human activity (e.g. deforestation, burning) to human activity (e.g. deforestation, burning) to form a plagioclimax.form a plagioclimax.

A plagioclimax can be maintained by A plagioclimax can be maintained by mowing, grazing or burning mowing, grazing or burning

Grassland ManagementGrassland Management

Grazing species – sheep, goats, Grazing species – sheep, goats, cattle, horses and llamascattle, horses and llamas

Each species has a preferred grazing Each species has a preferred grazing behaviour.behaviour.

Nutrient poor grassland is often rich Nutrient poor grassland is often rich in plant species, high densities of in plant species, high densities of cattle can produce nutrient rich but cattle can produce nutrient rich but species-poor grassland.species-poor grassland.

Effects of overstockingEffects of overstocking The growth rate of the grass can not The growth rate of the grass can not

support the amount of animals grazing on support the amount of animals grazing on the landthe land

Damaged vegetationDamaged vegetation Bare earthBare earth Increase in soil erosion by wind and rainIncrease in soil erosion by wind and rain

ExamplesExamples AustraliaAustralia St Helena in South AtlanticSt Helena in South Atlantic

Moorland ManagementMoorland Management

Heather moorland is a plagioclimax Heather moorland is a plagioclimax maintained by humans for game maintained by humans for game management, and also by grazing management, and also by grazing

Uncontrolled peat fires are disastrous Uncontrolled peat fires are disastrous and the desert-like aftermath if likely and the desert-like aftermath if likely to persist for decades.to persist for decades.

Effects of muirburn on Effects of muirburn on the landthe land

If the heather is burned infrequentlyIf the heather is burned infrequently The heather becomes too old and woody, and The heather becomes too old and woody, and

regrowth from the stem base is poor.regrowth from the stem base is poor. Poor regeneration, undesirable species spread Poor regeneration, undesirable species spread

e.g. brackene.g. bracken If heather is burned too frequentlyIf heather is burned too frequently

Decline in the carrying capacity of wildlife, Decline in the carrying capacity of wildlife, grazing and game species.grazing and game species.

Deplete soil of minerals and nutrient essential Deplete soil of minerals and nutrient essential for plant and animal growth.for plant and animal growth.

Spread of undesirables at the expense of the Spread of undesirables at the expense of the heather heather

Grassland – a Grassland – a plagioclimax maintained plagioclimax maintained

by grazingby grazing

Moorland – a Moorland – a plagioclimax maintained plagioclimax maintained

by muirburnby muirburn

Pupil ActivityPupil Activity

Read the handout – upland land Read the handout – upland land managementmanagement Highlight the main pointsHighlight the main points


Suggest what effects the following Suggest what effects the following might have on the numbers of might have on the numbers of grouse, and why:-grouse, and why:- More frequent burning of moorsMore frequent burning of moors Less frequent burning of moorsLess frequent burning of moors

This will be marked out of ten.This will be marked out of ten.

Food ProductionFood Production 2 2 main types of agricultural ecosystemmain types of agricultural ecosystem

Industrialised Industrialised uses large amounts of fossil fuel energy, water, uses large amounts of fossil fuel energy, water,

fertilisers and pesticides to increase net production.fertilisers and pesticides to increase net production. TraditionalTraditional

low input agricultural practices.low input agricultural practices.

11stst green revolution (1950s) green revolution (1950s) An increase in food production resulted from An increase in food production resulted from

increased yields per unit of farmed land.increased yields per unit of farmed land. 22ndnd green revolution (last 30 years) green revolution (last 30 years)

Use of fast growing, high yielding varieties of Use of fast growing, high yielding varieties of rice, corn and wheat.rice, corn and wheat.

More food from less land, increase in per More food from less land, increase in per capita food production.capita food production.

Two green revolutionsTwo green revolutions

Study the map showing countries Study the map showing countries whose crop yields per unit area of whose crop yields per unit area of land increased during the two green land increased during the two green revolutions.revolutions.

Summarise where the two industrial Summarise where the two industrial revolutions mainly took place.revolutions mainly took place.

Locations of major types Locations of major types of food productionof food production

Study the map, summarise the Study the map, summarise the locations of the world’s principal locations of the world’s principal types of food production.types of food production.

Make notes on each type of food Make notes on each type of food productionproduction

Questions on food Questions on food productionproduction

use the handout to help answer these use the handout to help answer these three questionsthree questions Suggest a reason for the decline in Suggest a reason for the decline in

per capita production of grain in the per capita production of grain in the last decadelast decade

Suggest two reasons why wheat is Suggest two reasons why wheat is the world’s most important cereal the world’s most important cereal crop.crop.

Suggest why rice is less important as Suggest why rice is less important as an export crop than wheat or maize.an export crop than wheat or maize.

Total world grain Total world grain productionproduction

World grain production per World grain production per capitacapita

Extensive farmingExtensive farming

Production of crops and livestock raised on Production of crops and livestock raised on land, which has little, or no fertiliser land, which has little, or no fertiliser added.added.

Annual yields very low.Annual yields very low. Examples – upland sheep, grain production Examples – upland sheep, grain production

in semi-arid areas, conifer forestry, some in semi-arid areas, conifer forestry, some meat and dairy farms.meat and dairy farms.

Upland areas in U.K. now in danger of Upland areas in U.K. now in danger of overstocking.overstocking.

Intensive farmingIntensive farming

This is an open system; there is a net loss This is an open system; there is a net loss of nutrients as large yields are being of nutrients as large yields are being exported from the farms, which then has exported from the farms, which then has to be replaced by fertilisers.to be replaced by fertilisers.

Animals are farmed at high densities, Animals are farmed at high densities, which increase the chance of catching which increase the chance of catching diseases due to stress, and overcrowding, diseases due to stress, and overcrowding, this leads to antibiotics being added to this leads to antibiotics being added to their food.their food.

ComparisonComparisonintensive and extensive intensive and extensive

farmingfarming

Yields are given in nitrogen per Yields are given in nitrogen per hectarehectare

Extensive farms Extensive farms 1-20Kg/hectare1-20Kg/hectare

Intensive farms Intensive farms 15 – 40kg/hectare for lowland animals 15 – 40kg/hectare for lowland animals > 150Kg for vegetable crops> 150Kg for vegetable crops


With the use of a highlighter, read With the use of a highlighter, read the handout on intensive farming – the handout on intensive farming – advantages and disadvantages.advantages and disadvantages.

GMO TechnologyGMO Technology

Read the article “Science Friction”, Read the article “Science Friction”, taken from the BBC Wildlife taken from the BBC Wildlife magazine.magazine.

Answer the questions provided.Answer the questions provided.

With the use of a highlighter – read With the use of a highlighter – read through the additional photocopies through the additional photocopies on GMO technology.on GMO technology.

General environmental General environmental effects of food effects of food

productionproduction

General environmental effects of food production


productionproduction ““The variability among living The variability among living organisms from all sources organisms from all sources including terrestrial, marine including terrestrial, marine and other aquatic and other aquatic ecosystems and the ecosystems and the ecological complexes of ecological complexes of which they are part; this which they are part; this includes diversity within includes diversity within species, between species species, between species and ecosystems”and ecosystems”

Convention on Biological Convention on Biological Diversity, Rio 5Diversity, Rio 5thth June June 19921992

Major changes in agricultural Major changes in agricultural activity in the U.K. since the activity in the U.K. since the

1940’s1940’s Increasing levels of farm mechanisation, Increasing levels of farm mechanisation,

energy inputs and decline in the labour energy inputs and decline in the labour forceforce

Development of highly productive strains Development of highly productive strains of crops and livestockof crops and livestock

Increasing use of fertilisers and pesticides.Increasing use of fertilisers and pesticides. Changes in farm sizes.Changes in farm sizes. Changes in farming practices and Changes in farming practices and

significance of different crops.significance of different crops. Financial returns.Financial returns.


Diagram – Diagram – consequences of consequences of modernisation of agriculture on modernisation of agriculture on ecology and wildlife interests of ecology and wildlife interests of farmland.farmland. Stick the diagram into your bookStick the diagram into your book Write out a paragraph discussing the Write out a paragraph discussing the

diagram, including any comments that diagram, including any comments that you can draw form the diagram.you can draw form the diagram.

Pollution from farm Pollution from farm wasteswastes

Arable Farming Arable Farming Nitrogen from fertilisers can build up in the Nitrogen from fertilisers can build up in the

soil. Soil bacteria then convert this to soil. Soil bacteria then convert this to nitrates. The nitrates then get into stream nitrates. The nitrates then get into stream and river systems through surface run off.and river systems through surface run off.

Livestock FarmingLivestock Farming Stackable manureStackable manure Slurry Slurry

kept in large tanks or lagoonskept in large tanks or lagoons can be spread on fields as fertilisers, but can be spread on fields as fertilisers, but

often has the wrong N:P:K ratio.often has the wrong N:P:K ratio. If animals are kept enclosed, then the If animals are kept enclosed, then the

problem of manure disposal increases.problem of manure disposal increases.

Pollution from Farm Pollution from Farm WastesWastes

Specialisation of farmingSpecialisation of farming Livestock farms, which have excess slurry, are Livestock farms, which have excess slurry, are

often nowhere near arable farms.often nowhere near arable farms. This leads to accidental or deliberate leakage This leads to accidental or deliberate leakage

of slurry, which finds its way into watercourses. of slurry, which finds its way into watercourses. This contributes to eutrophication. This contributes to eutrophication.

Other problems from farm waste include Other problems from farm waste include growth hormones and antibiotics which growth hormones and antibiotics which the animals are fed with.the animals are fed with.

Land reclamation for Land reclamation for agricultureagriculture

Fertile land is highly valued, and there is a Fertile land is highly valued, and there is a strong drive to get more land under strong drive to get more land under intensive farming.intensive farming.

This can lead to problems when the land is This can lead to problems when the land is either a National Park or low-lying wetlands.either a National Park or low-lying wetlands.

Land reclamation for agriculture destroys Land reclamation for agriculture destroys important marine defences and freshwater important marine defences and freshwater marsh habitats.marsh habitats.

Land reclaimed from the sea, needs Land reclaimed from the sea, needs constant maintenance of sea defences, constant maintenance of sea defences, which is expensive.which is expensive.

Hedgerow DestructionHedgerow Destruction

Hedgerow Hedgerow nnarrow belt of vegetation dominated by arrow belt of vegetation dominated by

shrubs and occasional trees.shrubs and occasional trees.

Traditionally hedgerows served two Traditionally hedgerows served two functionsfunctions A barrier to the movement of livestock.A barrier to the movement of livestock. Marking property boundaries.Marking property boundaries.

Hedgerows have a high Hedgerows have a high landscape and conservation landscape and conservation

valuevalue They are a traditional feature of the They are a traditional feature of the

landscape and add diversity to it.landscape and add diversity to it. Provide foraging, roosting and nesting Provide foraging, roosting and nesting

sites for birds.sites for birds. Rich in plant and animal species.Rich in plant and animal species. Act as a source of beneficial insects.Act as a source of beneficial insects. Act as Act as wildlife corridorswildlife corridors through an through an

increasingly hostile agricultural landscape.increasingly hostile agricultural landscape.

Hedgerow lossesHedgerow losses

Estimated that between 1945 and Estimated that between 1945 and 1970 there was an annual loss of 1970 there was an annual loss of about 8,000km yearabout 8,000km year-1-1 in the U.K. in the U.K.

In the 1990’s it is estimated that the In the 1990’s it is estimated that the U.K. was still losing 5,000 – 6,000 Km U.K. was still losing 5,000 – 6,000 Km yearyear-1-1..

Advantages of Hedgerow Advantages of Hedgerow removal to the farmerremoval to the farmer

Hedgerows act as a refuge for Hedgerows act as a refuge for weeds, diseases and crop pests.weeds, diseases and crop pests.

Reduce the loss of crop yields Reduce the loss of crop yields adjacent to the hedgeadjacent to the hedge

Bigger field sizes – decreases the Bigger field sizes – decreases the amount of land needed for turning amount of land needed for turning machinery.machinery.

Disadvantages of Disadvantages of Hedgerow removal to the Hedgerow removal to the

farmerfarmer Increases soil erosionIncreases soil erosion Reduce crop yields through the loss Reduce crop yields through the loss

of beneficial insect speciesof beneficial insect species Predators for pest controlPredators for pest control PollinatorsPollinators


On one side of A4 paperOn one side of A4 paper Compare and contrast intensive and Compare and contrast intensive and

extensive farming extensive farming (15 marks)(15 marks)

Using a highlighter – read through Using a highlighter – read through the three articles on farming from the three articles on farming from the BBC Wildlife magazine.the BBC Wildlife magazine.

History of Organic History of Organic FarmingFarming

Organic farming can be split into two Organic farming can be split into two categories:categories: Natural form of farming. E.g. traditional small Natural form of farming. E.g. traditional small

scale or subsistence farmers.scale or subsistence farmers. A recent development seeing a move from A recent development seeing a move from

intensive farming to organic farming where the intensive farming to organic farming where the aim is to produce food crops by building up soil aim is to produce food crops by building up soil fertility using the minimum of non-renewable fertility using the minimum of non-renewable resources and minimum damage to resources and minimum damage to environment.environment.

UK Register of organic food standardsUK Register of organic food standards This is a monitoring association, which checks This is a monitoring association, which checks

farmers fulfil criteria governed by EU farmers fulfil criteria governed by EU regulations.regulations.

ReadingReading

Handout – the advantages and Handout – the advantages and disadvantages of organic farmingdisadvantages of organic farming

Pages 19-20 of environmental Pages 19-20 of environmental biology – biology – looks at the advantages looks at the advantages and disadvantages to the and disadvantages to the environment and to the consumer.environment and to the consumer.

Traditional Traditional Farming MethodsFarming Methods

Crop rotationCrop rotation

IntercroppingIntercropping

Crop Rotation Crop Rotation A different crop is grown in the field each A different crop is grown in the field each

year. Once every few years a crop of year. Once every few years a crop of legumes is used to increase the nitrogen legumes is used to increase the nitrogen content of the soil.content of the soil.

Nitrogen fixation is the reduction of Nitrogen fixation is the reduction of atmospheric Natmospheric N22 to the ammonium ion, NH to the ammonium ion, NH

44++..

Rhizobium Rhizobium are nitrogen-fixing bacteria. are nitrogen-fixing bacteria. RhizobiumRhizobium live in root nodules of legumes live in root nodules of legumes e.g. peas, beans, clovers and peanutse.g. peas, beans, clovers and peanuts

Crop Rotation Crop Rotation

The enzyme responsible for nitrogen The enzyme responsible for nitrogen fixation is nitrogenase, farmers are looking fixation is nitrogenase, farmers are looking at breeding (through genetic engineering) at breeding (through genetic engineering) the ability of Nthe ability of N22 fixation in crops e.g. rice fixation in crops e.g. rice

and wheatand wheat Crop rotation is used as a form of Crop rotation is used as a form of

biological pest control, as it reduces the biological pest control, as it reduces the survival of weeds, pests and diseases survival of weeds, pests and diseases specific to particular crops.specific to particular crops.

IntercroppingIntercropping Small farms increase yields by growing more than Small farms increase yields by growing more than

one crop in the same field at the same time.one crop in the same field at the same time. Crops can be grown in rows or all mixed together.Crops can be grown in rows or all mixed together. Common in tropical areas where the growing Common in tropical areas where the growing

season lasts all year round.season lasts all year round. The main principle of intercropping is to increase The main principle of intercropping is to increase

overall yield of land available by growing different overall yield of land available by growing different and complementary plants together.and complementary plants together.

E.g. short and tall, annuals and perennials, legumes E.g. short and tall, annuals and perennials, legumes and high nitrogen requirersand high nitrogen requirers

Advantages of Advantages of IntercroppingIntercropping

Decrease in soil erosion, due to Decrease in soil erosion, due to harvesting of crops at different harvesting of crops at different times.times.

biological pest control, this can biological pest control, this can reduce pest damage by up to 80%, reduce pest damage by up to 80%, as predators for pests of one crop as predators for pests of one crop hide in another.hide in another.


Discuss the use of intercropping and Discuss the use of intercropping and crop rotation with legumes as a crop rotation with legumes as a method of cultivating crops in method of cultivating crops in developing countries.developing countries.

Biological Pest Biological Pest ControlControl

Use of natural predators, parasites or Use of natural predators, parasites or disease organisms to control pests on disease organisms to control pests on

field crops and in glasshousesfield crops and in glasshouses

Pests that can be controlled include Pests that can be controlled include insects, fungi, nematodes and weeds.insects, fungi, nematodes and weeds.

Two types of Biological Two types of Biological Pest ControlPest Control

Open farmland – basic biological control, Open farmland – basic biological control, where natural wildlife predators are where natural wildlife predators are encouraged. encouraged. hoverfly larvae and ladybirds eat greenfly.hoverfly larvae and ladybirds eat greenfly.

Enclosed cultivation in greenhouses and Enclosed cultivation in greenhouses and glass house systems. One predator is glass house systems. One predator is actively released into an enclosed area.actively released into an enclosed area. parasitic wasp, parasitic wasp, EncarsiaEncarsia, controls white fly , controls white fly

infestation of plants. infestation of plants.

Advantages of Biological Advantages of Biological Pest ControlPest Control

Avoids the use of chemical spraysAvoids the use of chemical sprays Pesticides may be so damaging to Pesticides may be so damaging to

natural predators what it allows pest natural predators what it allows pest species to increase.species to increase. e.g. cabbage white butterflye.g. cabbage white butterfly

Disadvantages of Disadvantages of Biological Pest ControlBiological Pest Control

Time lag to allow natural predator Time lag to allow natural predator populations to build uppopulations to build up

Predator population may be affected by Predator population may be affected by pesticide use in neighbouring areaspesticide use in neighbouring areas

In enclosed sites, control species may In enclosed sites, control species may have to be bought and released.have to be bought and released.

Introduce predator which may escape or Introduce predator which may escape or lead to its own problemslead to its own problems e.g. Polynesia and the introduction of the giant e.g. Polynesia and the introduction of the giant

African land snail (pg 23 – Env. Biology)African land snail (pg 23 – Env. Biology)

Biological ControlBiological Control

Snail genus Snail genus PartulaPartula in Polynesia, African in Polynesia, African Land Snail Land Snail AchatinaAchatina introduced in 1960s as introduced in 1960s as human food source – escaped from human food source – escaped from captivity and ate native vegetation and captivity and ate native vegetation and crops, introduced small predator snail crops, introduced small predator snail EuglandinaEuglandina to kill giant snails. to kill giant snails.

But it ate natives instead – wiped out 40 But it ate natives instead – wiped out 40 species, now only species, now only PartulaPartula left live in left live in captivity as captivity as Achatina Achatina keeps on munching!keeps on munching!


Question 3 – Specimen Exam PaperQuestion 3 – Specimen Exam Paper Peach potato aphidPeach potato aphid

Integrated Pest Integrated Pest ManagementManagement

In IPM, each crop and its pests are In IPM, each crop and its pests are evaluated as part of an ecological system. evaluated as part of an ecological system. A control programme is developed that A control programme is developed that includes a sequence of crop management, includes a sequence of crop management, and biological and chemical controls.and biological and chemical controls.

The aim of IPM is not pest eradication but The aim of IPM is not pest eradication but a reduction in crop damage to an a reduction in crop damage to an economically tolerable level. Well economically tolerable level. Well managed IPM systems are recognised as managed IPM systems are recognised as being economically and ecologically being economically and ecologically sound.sound.

Crop Monitoring Crop Monitoring

1.1. Cultivation controlsCultivation controls

2.2. Biological controlsBiological controls

3.3. Targeted pesticide useTargeted pesticide use

Revision ActivityRevision Activity

The land DebateThe land Debate Handout – scene setting, character Handout – scene setting, character

cards.cards.

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