212-2 How Is Food Produced?Concept 12-2A We have sharply increased crop production using a mix of industrialized and traditional agriculture.Concept 12-2B We have used industrialized and traditional methods to greatly increase supplies of meat, fish, and shellfish.
3Food Production Has Increased Dramatically Three systems produce most of our foodCroplands: 77%Rangelands, pastures, and feedlots: 16%Aquaculture: 7%Importance of wheat, rice, and cornTremendous increase in global food production
4Industrialized Crop Production Relies on High-Input Monocultures Industrialized agriculture, high-input agricultureGoal is to steadily increase crop yieldPlantation agriculture: cash cropsIncreased use of greenhouses to raise crops
5Traditional Agriculture Often Relies on Low-Input Polycultures Traditional subsistence agricultureTraditional intensive agriculturePolycultureBenefits over monoculture - biodiversitySlash-and-burn agriculture
6Science Focus: Soil Is the Base of Life on Land Soil compositionSoil formationLayers (horizons) of mature soilsO horizon: leaf litterA horizon: topsoilB horizon: subsoilC horizon: parent material, often bedrockSoil erosion(consider watching this video at home.)
8A Closer Look at Industrialized Crop Production Green Revolution: increase crop yieldsMonocultures of high-yield key cropsE.g., rice, wheat, and cornUse large amounts of fertilizers, pesticides, and waterMultiple croppingSecond Green RevolutionWorld grain has tripled in production
9Crossbreeding and Genetic Engineering Can Produce New Crop Varieties Gene RevolutionCross-breeding through artificial selectionSlow processGenetic engineeringGenetic modified organisms (GMOs): transgenic organismsRoundup Ready Soy
10Meat Production and Consumption Have Grown Steadily Animals for meat raised inPasturesFeedlotsMeat production increased fourfold between 1961and 2007Demand is expected to go higherWhy?
1112-3 What Environmental Problems Arise from Food Production? Concept Food production in the future may be limited by its serious environmental impacts, including soil erosion and degradation, desertification, water and air pollution, greenhouse gas emissions, and degradation and destruction of biodiversity.
12Major Harmful Environmental Effects on Food Production
13Topsoil Erosion Is a Serious Problem in Parts of the World Natural causesHuman causesTwo major harmful effects of soil erosionLoss of soil fertilityWater pollution
14Rill or Gully?Rill – small channel cut in soil by runoff water (more V-shaped)Rill erosion can become gully erosion when the rill becomes so eroded that you can’t drive equipment over it easily. (more u-shaped) “Gully washer”
15Natural Capital Degradation: Global Soil Erosion
16Drought and Human Activities Are Degrading Drylands Desertification – Caused by:OvergrazingCultivation of marginal landsDestruction of vegetation for fuel woodEffect of globalwarming
17Natural Capital Degradation: Desertification of Arid and Semiarid Lands
18Excessive Irrigation Has Serious Consequences Irrigation problemsSalinization – Irrigated soils develop excess salt content (irrigation water has dissolved mineralswhichaccumulate.(not the sameas desalinationWaterloggingToo much water“drowns” roots
19Trade-Offs: Genetically Modified Crops and Foods
20Food and Biofuel Production Systems Have Caused Major Biodiversity Losses Biodiversity threatened when forest and grasslands are replaced with croplandsAgrobiodiversity threatened when Human-engineered monocultures are usedImportance of seed banksNewest: underground vault in the Norwegian Arctic
2212-4 How Can We Protect Crops from Pests More Sustainably? Concept We can sharply cut pesticide use without decreasing crop yields by using a mix of cultivation techniques, biological pest controls, and small amounts of selected chemical pesticides as a last resort (integrated pest management).
23Nature Controls the Populations of Most Pests What is a pest?Natural enemies—predators, parasites, disease organisms—control pestsIn natural ecosystemsIn many polyculture agroecosystemsWhat will happen if we kill the pests?Spiders are important natural predators
24We Use Pesticides to Try to Control Pest Populations InsecticidesHerbicidesFungicidesRodenticidesHerbivores overcome plant defenses through natural selection: coevolution
25Modern Synthetic Pesticides Have Several Disadvantages Accelerate the development of genetic resistance to pesticides by pest organismsExpensive for farmersSome insecticides kill natural predators and parasites that help control the pest populationPollution in the environmentSome harm wildlifeSome are human health hazards
26There Are Alternatives to Using Pesticides Fool the pestProvide homes for pest enemiesImplant genetic resistanceBring in natural enemiesUse insect perfumesE.g., pheromonesScald them with hot water
27Integrated Pest Management Is a Component of Sustainable Agriculture Integrated pest management (IPM)Coordinate: cultivation, biological controls, and chemical tools to reduce crop damage to an economically tolerable levelDisadvantages
2812-5 How Can We Improve Food Security? Concept We can improve food security by creating programs to reduce poverty and chronic malnutrition, relying more on locally grown food, and cutting food waste.
29Use Government Policies to Improve Food Production and Security Control pricesProvide subsidiesLet the marketplace decideUnited Nations Children’s Fund (UNICEF) suggests these measuresImmunizing children against childhood diseasesEncourage breast-feedingPrevent dehydration in infants and childrenProvide family planning servicesIncrease education for women
3012-6 How Can We Produce Food More Sustainably? Concept 12-6A Sustainable food production will require reducing topsoil erosion, eliminating overgrazing and overfishing, irrigating more efficiently, using integrated pest management, promoting agrobiodiversity, and providing government subsidies for more sustainable farming, fishing, and aquaculture.Concept 12-6B Producing enough food to feed the rapidly growing human population will require growing crops in a mix of monocultures and polycultures and decreasing the enormous environmental impacts of industrialized food production.
31Reduce Soil Erosion Soil conservation, some methods Terracing Contour plantingStrip cropping with cover cropAlley cropping, agroforestryWindbreaks or shelterbedsConservation-tillage farmingNo-tillMinimum tillageIdentify erosion hotspots
35Efficiency of Converting Grain into Animal Protein
36Shift to More Sustainable Agriculture Benefits of organic farmingStrategies for more sustainable agricultureResearch on organic agriculture with human nutrition in mindShow farmers how organic agricultural systems workSubsidies and foreign aidTraining programs;college curricula