AgricultureAgriculture

Chapters 9Chapters 9

US FarmingUS Farming

3% of workforce3% of workforce Family Farm vs Corporate FarmFamily Farm vs Corporate Farm SubsidiesSubsidies

To grow (Commodity)To grow (Commodity) Not to grow (Conservation)Not to grow (Conservation) DisasterDisaster Farm Subsidies Database

Top 10 World’s Food Crops 2010 :Top 10 World’s Food Crops 2010 :

By Quantity:By Quantity: Sugar CaneSugar Cane Corn Corn RiceRice WheatWheat PotatoesPotatoes SoySoy CassavaCassava Sugar BeetSugar Beet TomatoesTomatoes BarleyBarley

By Value:By Value:*Rice*Rice*Wheat (#2 US)*Wheat (#2 US)*Soy (#3 US)*Soy (#3 US)TomatoesTomatoesSugar CaneSugar CaneCorn (#1 US)Corn (#1 US)PotatoesPotatoesGrapesGrapesApplesApplesBananasBananas

http://faostat.fao.org/site/339/default.aspx

Cassava Root, native to South America. Leaves are edible as well

Sorghum, used as a grain for making flatbreads

Barley, an edible grain used as fodder and for alcohol production

Manioc

Sugar beet

54% of US sugar

Sorghum Soybean

CropsCrops Cash/CommodityCash/Commodity: for selling & trading large scale: for selling & trading large scale

Food Crops Food Crops Includes coffee, teaIncludes coffee, tea

Non food:Non food: Fiber: cotton, hempFiber: cotton, hemp Biofuel: switchgrass, cornBiofuel: switchgrass, corn Pharmaceutical: tobaccoPharmaceutical: tobacco Biopolymer: latex, cornBiopolymer: latex, corn

ForageForage: for animal feed. : for animal feed. Alfalfa, sorghum, hay, cornAlfalfa, sorghum, hay, corn

Subsistence: used directly by farmer for food/feedSubsistence: used directly by farmer for food/feed

Food-Fuel Connection Food-Fuel Connection Use of food crop land to grow plants for Use of food crop land to grow plants for

biofuels: Biodiesel, ethanolbiofuels: Biodiesel, ethanol Corn, switchgrass, soy, sorghumCorn, switchgrass, soy, sorghum

Cost of fuel for farm equipment, delivery, Cost of fuel for farm equipment, delivery, processingprocessing

Petroleum used to make pesticides & Petroleum used to make pesticides & fertilizers.fertilizers.

Monocultures:Monocultures: One type of crop (corn field, sod, etc)One type of crop (corn field, sod, etc) PestsPests Degrades Soil FertilityDegrades Soil Fertility Use of PesticidesUse of Pesticides

Iowa Corn field: Corn Borer Heaven!

Soil Horizons

Soil HorizonsSoil Horizons ‘‘O’ : Organic Layer; decaying matter, O’ : Organic Layer; decaying matter,

leaf litterleaf litter ‘‘A’ : Topsoil. Darker than O, most A’ : Topsoil. Darker than O, most

nutrient rich. Lots of organic matternutrient rich. Lots of organic matter ‘‘E’ : Minerals leach out (leave) here and E’ : Minerals leach out (leave) here and

accumulate belowaccumulate below ‘‘B’ : light color, dense, low organic B’ : light color, dense, low organic

contentcontent ‘‘C’ : transition between soil & parent rockC’ : transition between soil & parent rock ‘‘R’ : Parent material, bedrockR’ : Parent material, bedrock

Changes in SoilChanges in Soil Erosion. Erosion.

Fertile Soil directly exposed to the elements. Fertile Soil directly exposed to the elements. Not rotating crops Not rotating crops Poor Tilling practicesPoor Tilling practices

Slash and Burn (swidden) Agriculture: clearing Slash and Burn (swidden) Agriculture: clearing areas of rainforest through controlled burning.areas of rainforest through controlled burning. Ash fertilizes soil, pests are removed. Ash fertilizes soil, pests are removed. Soil quality declines over time, then new area Soil quality declines over time, then new area

is selected.is selected.

Erosion due to not rotating crops; most damage occurred within two years.

Erosion (cont.)Erosion (cont.)

Increased Sedimentation downstreamIncreased Sedimentation downstream Increases toxins in water (heavy metals, nitrates, Increases toxins in water (heavy metals, nitrates,

ammonia)ammonia) Increases EutrophicationIncreases Eutrophication Leads to Biomagnificaton:Leads to Biomagnificaton:

Dust Bowl of the 1930sDust Bowl of the 1930s Video ClipVideo Clip

SalinizationSalinization of soilof soil Increased Soil SalinityIncreased Soil Salinity

Aquifers w/dissolved minerals used for irrigationAquifers w/dissolved minerals used for irrigation Water evaporates, leaves concentrated salt Water evaporates, leaves concentrated salt

behindbehind

To Prevent:To Prevent: Low water cropsLow water crops Drip irrigationDrip irrigation Use water w/low salt contentUse water w/low salt content

To mitigateTo mitigate Allow rain/irrigation to flush out saltAllow rain/irrigation to flush out salt Use salt-tolerant cropsUse salt-tolerant crops Strip CroppingStrip Cropping

Soil SustainabilitySoil Sustainability Contour Plowing: Land is plowed along its Contour Plowing: Land is plowed along its

contours, contours, perpendicularperpendicular to slope. Reduces to slope. Reduces erosion through runoff.erosion through runoff.

Terracing: decrease runoffTerracing: decrease runoff No-Till Agriculture: No plowing. Herbicides No-Till Agriculture: No plowing. Herbicides

are used to manage (not eliminate) weedsare used to manage (not eliminate) weeds

Example of No-Till Agriculture. Sunflowers are planted in the leftover wheat stubble from previous season. Stubble acts as mulch, keeping moisture in.

Rice Terraces in the Philippines 2004 http://en.wikipedia.org/wiki/Terrace_(agriculture)

Terraced Rice Fields in Yunnan Province, China 2003

DesertificationDesertification

About 1/3 of land should be desertAbout 1/3 of land should be desert ~43% actually is. Occurs in poorest ~43% actually is. Occurs in poorest

countriescountries Causes:Causes:

Poor farming & forestry practicesPoor farming & forestry practices Conversion of ranges to cropland in marginal Conversion of ranges to cropland in marginal

areasareas Poisoning of SoilPoisoning of Soil Climate changeClimate change

Prevention Desertification:Prevention Desertification: Monitoring symptomsMonitoring symptoms Proper soil, forest conservationProper soil, forest conservation IrrigationIrrigation Use of WindbreaksUse of Windbreaks

Example of a Windbreak

Strip CroppingStrip Cropping

Planting crop in every other row; leave Planting crop in every other row; leave the other row permanently fallowthe other row permanently fallow

Helps stop erosion by creating a natural Helps stop erosion by creating a natural damdam

Helps pull salt away from crops through Helps pull salt away from crops through capillary actioncapillary action

Useful on steep slopesUseful on steep slopes

Area of strip cropping in Wisconsinhttp://en.wikipedia.org/wiki/File:Strip_farming_in_Wisconsin,_USA,_1957.jpg