Advanced Placement Environmental Science

1. Industrialized Agriculture

2. Plantation Agriculture

3. Traditional Subsistence Agriculture

4. Traditional intensive agriculture

AKA High-input Agriculture Uses large amounts of: fossil fuel energy water commercial fertilizers and pesticides to produce huge quantities of single crops

(monoculture) or livestock.

Form of industrialized agriculture used primarily in tropical developing countries.Cash crops such as:Bananas, coffee, soybeans, sugarcane, cocoa and veggies.Monoculture cropsLivestock production raised in feedlots.

2 Types which are practiced by 2.7 billion people (43%) of world’s population in developing countries—provides 20% o world’s food supply.

1) traditional subsistence2) traditional intensive agriculture

Traditional Subsistence Agriculture

Traditional Intensive Agriculture

Uses mostly human labor & animals to produce enough crops & livestock for a farm family’s survival.

Ex: low-input type includes shifting cultivation and nomadic livestock.

Farmers incr their inputs of human labor, fertilizer and water to gain increased yield.

Produce enough food to feed their families and to sell for income.

Soils: FormationSoils: FormationSoils: FormationSoils: Formation• Soil horizonsSoil horizons• Soil horizonsSoil horizons • Soil profile Soil profile • Soil profile Soil profile • Humus Humus • Humus Humus

O horizonO horizonLeaf litterLeaf litter

A horizonA horizonTopsoilTopsoil

B horizonB horizonSubsoilSubsoil

C horizonC horizonParentParent

materialmaterial

Mature soilMature soil

Young soilYoung soil

RegolithRegolithRegolithRegolith

BedrockBedrockBedrockBedrock

Immature soilImmature soil

Fig. 10.12, p. 220

Soil PropertiesSoil PropertiesSoil PropertiesSoil Properties

• Infiltration H2OInfiltration H2O• Infiltration H2OInfiltration H2O

• Leaching NutrientsLeaching Nutrients• Leaching NutrientsLeaching Nutrients

• Porosity/permeabilityPorosity/permeability• Porosity/permeabilityPorosity/permeability

• TextureTexture• TextureTexture

• StructureStructure• StructureStructure

• pHpH• pHpH

100%clay100%clay

IncreasingIncreasingpercentage siltpercentage silt

IncreasingIncreasingpercentage claypercentage clay

00

2020

4040

6060

8080

8080

6060

4040

2020

00100%sand100%sand 8080 6060 4040 2020 100%silt100%silt

Increasing percentage sandIncreasing percentage sand

Fig. 10.16, p. 224

Water Water

High permeability Low permeability

Fig. 10.17, p. 224

Texture Nutrient Infiltration Water-Holding Aeration TilthCapacity Capacity

Clay Good Poor Good Poor Poor

Sand Poor Good Poor Good Good

Loam Medium Medium Medium Medium Medium

Acidity / Alkalinity – pH Major Nutrients (N-P-K)

◦Nitrogen◦Phosphorus (phosphates)◦Potassium (potash)

Proper pH directly affects the availability of plant food nutrients

Soil is best if between pH 6 – 8 (except for certain acid loving plants)◦ ‘Sour’ if too acidic◦ ‘Sweet’ if too basic

Too acidic or basic will not ◦ Allow compounds to dissolve◦ Allow presence of certain ions

If soil is too acidic, add ground limestone If soil is too basic, add organic material like

steer manure

Importance◦ Stimulates above ground growth◦ Produces rich green color◦ Influences quality and protein

content of fruit ◦ A plant’s use of other elements is

stimulated by presence of N Taken up by plant as NH4

+ and NO3

-

Replenished naturally by rhizobacteria on legume roots

Fertilizer from manure or Chemical rxn.

Abundant in◦Strong root system◦Increases seed yield and fruit development

◦Parts of root involved in water uptake (hair)

Major role in transfer of energy Taken up by plant as H2PO4

- and HPO4

-2

Fertilizer is made from rock phosphate

Potash Important in vigor and vitality of plant

◦ Carries carbohydrates through the plant◦ Improves color of flowers◦ Improves quality of fruit◦ Promotes vigorous root systems◦ Offsets too much N

Found naturally in feldspar and micas

Plant production can be no

greater than that level

allowed by the growth factor present in the lowest amount relative to the

optimum amount for that

factor

Two most important factors that determine climate are Temperature and Moisture and they affect◦Weathering processes◦Microenvironmental conditions for soil organisms

◦Plant growth◦Decomposition rates◦Soil pH◦Chemical reactions in the soil

Refers to the rock and minerals from which the soil derives.

The nature of the parent rock has a direct effect on the soil texture, chemistry and cycling pathways.

Parent material may be native or transported to area by wind , water or glacier.

Soils develop in response to

ClimateLiving organismsParent MaterialTopographyTime

Physical characteristics of location where soil is formed.◦Drainage◦Slope direction◦Elevation◦Wind exposure

Viewed on Macro-scale (valley) or microscale (soil type in field)

After enough time, the soil may reach maturity.◦Depends on previous factors◦Feedback of biotic and abiotic factors may preserve or erode mature profile.

Physical/Mechanical includes temperature

changes (freezing and thawing, thermal expansion), crystal growth, pressure, plant roots, burrowing animals

causes disintegration of parent material and facilitates chemical weathering

Chemical always in water includes hydration,

hydrolysis, oxidation, reduction, carbonation and exchange

examples :◦ oxidation of Fe to form

limonite, deposited in joints, inhibits groundwater flow

◦ hydrolysis of feldspars to form clay (kaolin) - forms infill for joints

Gravitational movement of weathered rock down slope without aid of water or wind (landslips)

transported material is called colluvium often set off by man’s activity can involve very small to immense volumes of

material sliding, toppling, unravelling, slumping controlled by discontinuities (joints, bedding,

schistocity, faults etc)

Sheet erosion◦ by water flowing down valley sides ◦ severe when vegetation removed and geological

materials uncemented Stream erosion

◦ materials brought downslope by mass wasting and sheet erosion are transported by streams

◦ erosion by the streams - meanders etc

Forms by dissolution of limestone - limestone is only common rock soluble in water - dissolved carbon dioxide in rain water

form highly variable ground conditions formation of sink holes - when buried leads

to surface subsidence