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 crops  Livestock 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 subsistence 2) 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: Formation Soil horizonsSoil horizons Soil profileSoil profile HumusHumus O horizon Leaf litter A horizon Topsoil B horizon Subsoil C horizon Parentmaterial Mature soil Young soil RegolithRegolith BedrockBedrock Immature soil Fig , p. 220

Soil Properties Infiltration H2OInfiltration H2O Leaching NutrientsLeaching Nutrients Porosity/permeabilityPorosity/permeability TextureTexture StructureStructure pHpH 100%clayIncreasing percentage silt Increasing percentage clay %sand %silt Increasing percentage sand Fig , p. 224 Water High permeabilityLow permeability Fig , p. 224

TextureNutrientInfiltrationWater-HoldingAerationTilthCapacity ClayGoodPoorGoodPoorPoor SandPoorGoodPoorGoodGood Loam MediumMediumMediumMediumMedium

 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 NH 4 + and NO 3 -  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 H 2 PO 4 - and HPO 4 -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  Climate  Living organisms  Parent Material  Topography  Time

 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