Soil and Agriculture

Soil and AgricultureChapter 14.1-14.2Chapter 12Things you will need to read on your ownfrom book or supplemental packet.Geology ConceptsLayers of the earthRock Cycle (how each formed)SedimentaryIgneousMetamorphicPlate TectonicsEarthquakes and volcanoes

Soil Properties and FormationSoil SummarySoil is formed viaChemical, mechanical, or biological weathering

Soil is made ofGravel, Sand, Silt, and ClayOrganic material (humus)

Soil HorizonsO-organic matterA-topsoilB-subsoilC-subsoil

Soil CharacteristicsTexture and CompositionSoil ribbon/triangle

NutrientsN-P-K

Porosity and water-holding capacity

Maintaining Soil QualityErosion and degradation

Human NutritionFood security: all/most people have access to enough foodGlobal unequal access to foodwe do produce enoughNot everyone can afford to buy it

Food insecurity: all/most live with chronic hunger and poor nutritionthreatens lifestyleCaused by poverty, war, corruption, bad weather (climate change)interferes with transport/distribution1 in 6 people dont get enough to eat (less-developed)

We increase food security by decreasing environmental and harmful effects of industrialized agricultureChronic undernutrition: cant grow or buy enough to meet needs ~2200 kcal/day1 billion people worldwide! (less than 400 kcal)8.8 million people starve to death each year

Chronic malnutrition: diet deficient in protein or other nutrients; makes vulnerable to disease and hinders developmentLow income/less developed, 3 billion people

Famine: severe shortage of food resulting in mass starvation, caused by catastrophic events18% mortality rate

Overnutrition: food intake exceeds need. Obesity epidemicaffluent countries. 1.2 billion affected (300 million obese)

Nutrient RequirementsMacronutrientsprotein, carbs, fats, fiberMicronutrientsvitamins, minerals, elements

Agriculture has greatly improved the quality of the human diet since hunter-gatherer timesProduce more with industrialization but increase impact

Deficiencies result in stunted growth or diseasesVitamin AblindnessLow ironanemiaIodinegoiter (thyroid problems)

What do we eat? Food.We are considered specialistseat few available edible plant species14 of 50,000 plant species feed 90% of the worldCorn, rice, wheat (48%)

Select mammal and fish speciesBeef, veal, pork, lamb, chicken, turkey, duckMeat consumption increases with affluencemajority of world vegetarian

Makes us vulnerable to climate changesdiet not diverse enough to deal with catastrophic change.

Where does our food come from?CroplandsIndustrialized or Subsistence Farming

Rangelands, Pastures, and FeedlotsSmall farms vs. Factory farms

Fisheries and AquacultureIndustrial fishing or Farmed fishThe Green RevolutionA shift occurred in farming from human/animal labor to machinery with selective breeding of crops, genetic modification, and increased use of fertilizer and waterLed to higher yielding crops and disease resistanceIncreased use of fertilizer and improve irrigation technologyMonocultures of selectively-bred or GM crops

Ability to feed a growing population more effectively with less space

Negative ConsequencesMechanization: used machines instead of human/animal labor (fossil fuels), rely on monocultures (machines crop specific)Irrigation: deplete groundwater reserves, cause waterlogging and salinizationFertilizer: fossil fuels used to manufacture, runoff into waterways (algae growth)Monocropping: plant and harvest crops at the same time, leads to soil erosion and vulnerability to pestsPesticides: kill unwanted organisms, persistent in the environment, bioaccumulate, evolve resistanceCroplandsIndustrialized25% of all cropland supplies 80% of the worlds food.Heavy equipmentLots of moneyLots of fossil fuelsLots of water usedFertilizer and pesticidesMonocultures (single species)High yield per acre of land

**17% used for biofuel and 35% used to feed cattle

CroplandsPlantationsGrow cash cropsnot for human consumptionBanana, palm oil, soy, sugarcane

Greenhouses and hydroponicsCost more to produce, less impact on soilRequire large amounts of water and electricity

CroplandsSubsistence (small farming operations)Small growing operations, most to feed families or small communities75% of land produces 20% of worlds foodGrow polycultures (multiple species)traditional vs. intensiveSun, humans, and animals vs. Sun, human, animals, fertilizer (manure), and water

GM Cropsthe goodIncreased yield and crop qualityresistant to pests and harsh conditionsGolden rice

Reduce need for pesticidesRoundup ready gene

Increased profitsMore crops on same space

GM Cropsthe concernsSafe for human consumption?Banned in the EU

Effect biodiversityElimination of natural plant varieties through accidental breeding

Regulation and LabelingCurrently not regulated in the USVoluntary labelingOrganic= no GM

In the USCorn 63% Soy 91%Cotton 71%70% of food on store shelves contains something GM

Rangelands, Pastures, and Feedlots50% of meat comes from unfenced rangelands and pastures50% from Factory Farms

Veal calves, pigs, chickens and turkeys live in cages throughout their livesLarge environmental impactLarge demand for grain to feed animals

Rangelands, Pastures, and FeedlotsHigh-density farming (factory farms)56 BILLION animals are raised and slaughtered each yearMeat consumption rises with affluenceCAFOConcentrated Animal Feeding OperationBeef, poultry, dairy cow, hogs2500 hogs per building50,000 turkeys per buildingConfined and allowed little room to moveMinimized land cost, efficient feeding Antibiotics and supplements used due to high concentrationPerpetuates antibiotic resistant bacteriaWaste disposal concerns

Free-rangeAnimals can range part of the day outsideUSDA defines as spending part of the day outsideNo regulations on time, size, etc.Used as a marketing term

Grass-fedMostly used in beef, raised on pastures, small farmsfinished on grass, not fed a grain dietHealthier, less fat, more expensiveLess impact

Cage-freeNot confined to cages, able to move aroundAllowed to exhibit more normal behaviorStill live in highly concentrated areas, not cruelty-free

Fisheries and AquacultureRevisit commercial fishing practices and cause of fisheries collapseMost major fisheries could collapse during this century2.6 billion people depend on fish in their diet~37% of wild fish caught turned into fish meal for aquaculture

AquacultureChina worlds leader (carp, catfish, tilapia, shrimp, salmon)Farmed fish kept in enclosuresWastewater pumped into surrounding areaBacteria, viruses and antibioticsEscape and interbreed with native fishsome genetically modified

Concerns with Industrialized AgricultureHad an enormous increase in food production since 1950s with green revolutionMore food grown per acre, decreased amount of land used with a growing populationProtected biodiversityless land converted to farms.

Industrializing Agriculture is the worst mistake in human history.Why would we say this?CroplandCurrently at upper limit of productionNo way to increase total yieldCant irrigate, fertilize or genetically engineer more productivity

Meat ProductionRequires large amounts of energyWastes create pollutionErosionAntibiotic use

AquacultureDepleting wild populations to feed farmed fish6 lb wild fish to make 2 lb farmed salmonIncreased toxins in farmed fish (bioaccumulate)Waste productionInterbreed with wild fishSpread invasive speciesProblem: AgroecosystemsEcosystem created by agricultural practicescharacterized by lowGenetic diversitySpecies diversityHabitat diversity

Agroecosystems differ from natural ecosystems in five major ways:

Farming attempts to stop ecological successionSpecies diversity is low because farmers usually practice monoculture. Monoculture tends to soil fertilityFarmers plant species (crops) in an orderly fashion - this can make pest control more difficultFood chains are far more simple in agroecosystems because of pest control and other farming practicesPlowing is like no other natural disturbance - plowing can erosion and cause more nutrient loss (which is replaced by fertilizer)Problem: Topsoil Erosion and Soil DegradationSoil moved by wind and waterlargest causeWind problematic on dry flat landRoots help anchor soil and store nutrientsSevere erosion leads to gullies formingLose fertile soil via farming, deforestation, overgrazing and vehicle useEroding soil faster than it forms

**Causes loss of soil fertility and water pollution (sediment); pesticide residues enter water, alter chemical cycling

Problem: DesertificationProductive potential of topsoil falls by 10% or more due to drought, overgrazing, or deforestationModerate 10-25% decreaseSevere 26-50% decreaseVery Severe 51+% decrease

Only in extreme cases do new deserts form, usually borders of existing ones expandGlobally 70% of our dry lands are threatened (mostly in Africa)

Climate change is increasing drought conditions, which threaten food supplies

Problem: Irrigation70% of human water use is for irrigation

High concentration of salts dissolve into water from surrounding rock, as water evaporates into soil leaves behind salty residue (soil salinization)Lowers growth and kills plantsAffects 25% of the cropland in the US

Waterlogging of soil, raises water table and kills plantsDepletes groundwater reservoirs

Problem: Air PollutionGreenhouse gases (CO2, NO2, CH4) released through burning forests to clear the land (25% of total emissions)

Livestock generate 18% of all greenhouse gas emissions worldwidemostly methaneThis is equal to the emissions of 33 million cars!

Problem: Biodiversity LossRemoving tropical rainforests to plant cash cropsSugarcane, palm oil, soybeans

Release greenhouse gases into atmosphere faster than they can be removed

Our diet is limiteddont eat a wide variety of plantsLimits our ability to deal with climate change

Plant Food Sources250,000 plant species 3000 tried as crops 300 grown for food 100 species used on large scale for food 15 to 20 species provide vast majority (90%) of mans food needs

It takes about 16 pounds of grain to produce one pound of edible meatAnd ~2500 gallons of water!

Largest crop volumes provided by: wheat, rice, corn, potatoes, barleyWheat and rice supply ~60% of human caloric intake

Other Plant Food SourcesPotatoesBarleySweet PotatoCassava (source of tapioca)GrapeSoybeanOatsSorghumSugarcane

MilletBananaTomatoSugar BeetRyeOrangeCoconutCottonseedAppleYamPeanutWatermelonCabbageOnionBeanPeaSunflower SeedMango Problem: PesticidesTargets weeds, insects, fungi, microbes that threaten agricultureHarm natural pest controlsInsecticide, fungicide, herbicide, rodenticideImproves profits of the farmer

First developed from plant sources then moved to syntheticDDT was the firstUse increased with green revolution, those used today 10-100 times more toxicVary in targets (broad/narrow spectrum) and persistence

Controlled by the EPA, USDA, FDA1947, 1972 Federal Insecticide, Fungicide, and Rodenticide Act1996 Food Protection ActPesticides Pro and ConKill unwanted pests that carry disease (rats, mosquitoes, Tse-Tse flies)Increase food suppliesMore food means food is less expensiveEffective and fast-actingNewer pesticides are safer, more specific Reduces labor costs on farmsFood looks betterAgriculture is more profitableAccumulate in food chainPests develop resistance 500 species so farResistance creates pesticide treadmillEstimates are $5-10 in damage done for $1 spent on pesticidePesticide runoffDestroy bees - $200 millionThreaten endangered speciesAffect egg shell of birds5% actually reach pest~20,000 human deaths/yearSustainable AgricultureWhat can we do to make it better?

Improving Food SecurityPesticide AlternativesSoil ConservationMeat ConsumptionAlternatives to Industrialized PracticesImproving Food SecurityGovernment controlling prices (set upper limit)Good for consumer, lower profit for farmer

Subsidize sustainable practices

In developing countries, give farmers tools to get started

Private aid organizationsTarget hungry/malnourished childrenPesticide AlternativesPolyculture instead of monocultureIntercropping alternate rows of crops that have different pestsPlanting pest-repellent cropsMulch to control weedsNatural insect predators ladybugs, preying mantis, birdsRotating crops to disrupt insect cyclesUsing Pheromones to attract insects to trapsReleasing sterilized insectsIntegrated Pest Management (IPM)Specific to local ecosystemDifficult to implement

SoilErosionSoil conservationkeep land covered with vegetationTerrace sloped land (reduces runoff)Contour planting (plant rows across slope)Strip Cropping (alternate rows of crops)Agroforestry (plant in orchard rows)Windbreaks (reduce wind erosion)Limit Plowing (no till/low till)Identify erosion hotspotsFertility (fertilizer alternatives)Use organic fertilizers (manure, green manure, compost)Crop rotationSalinizationReduce irrigationGrow salt-tolerant cropsDesertificationReduce destructive activities to soil and impacts on climate changeMeat ConsumptionAquacultureRaise fish offshore in open ocean pensLand-based, closed loop facilities (reduce pollution)Eat lower on the fish food chain

Poultry and LivestockEat lessEat lower on the animal food chainEliminate feedlots (pastures and rangelands)More free-rangeAlternatives to Industrialized PracticesOrganic AgricultureNon GMOPesticide and synthetic fertilizer freeWould be less expensive if environmental costs were included in the price of industrial farming productsOrganic Foods Production Act 1990

Use renewable forms of energy

Buy Local! Waste Less!