arable land
land that can be cultivated to grow crops
grassland
fertile soil, speed of nutrients cycle very quick
rangeland
anywhere where one grazes livestock
topsoil
top 15-20 cm of soil that contains most of soil's organic matter
soil erosion
movement of soil components from one place to another by means of wind or water
2 major negative effects of erosion
1) loss of soil fertility due to depletion of plant nutrients 2) water pollution
sheet erosion
occurs when surface water or wind peel off thin layers of soil
rill erosion
occurs when fast-flowing surface water makes channels in the soil
gully erosion
occurs when fast-flowing water rivulets join together to cut wider and deeper ditches or gullies
food security act of 1985
farmers receive a subsidy for taking highly erodible land out of production and replanting it with soil saving plants for 10-15 years
subsidy
government paying money to people by tax breaks or directly paying
desertification
productive potential of land falls by 10% or more because of a combination of natural drought from climate change and human activities that reduce or degrade topsoil
causes of desertification
1) prolonged drought 2) overgrazing 3)deforestation
salinization
buildup of salt in the upper layers of soil; stunts crop growth, lowers crop yields, kills plants, and eventually ruins land
waterlogging
occurs when farmers apply large amounts of irrigation water to leach salts deeper into the soil
soil conservation
involves reducing soil erosion and restoring soil fertility; keeping soil covered with vegetation, eliminating plowing and tilling
tilling
breaking up and smoothing of soil for planting
conservation tilling
use of special tillers and planting machines that reduce disturbance of soil during planting: 1) increase crop yields 2) raises carbon content 3) lower used of water, pesticides, and tractor fuel; disadvantages: 1) expensive machinery 2) works better with
alley-cropping/agroforestry
crops planted in strips or alleys between trees and shrubs. Erosion-reducing method that reduces water loss, retain soil moisture and nutrients and biodiversity
windbreaks/shelterbelts
trees left around crop fields to produce wind erosion. Erosion-reducing method that helps retain soil moisture, increase productivity, provide beneficial animal habitats
terracing
growing food on steep slopes without depleting topsoil. Erosion-reducing method by retaining water and by controlling runoff
contour farming
involves plowing and planting crops in rows across the slope of the land rather than up and down. Erosion-reducing method
strip-cropping
planting alternating strips of row crops (corn, cotton) with crops that cover the oil (grasses, legumes). Erosion-reducing method by reducing water runoff
organic fertilizer
made from plants and animal material. Include animal manure, which adds organic nitrogen and stimulates beneficial soil bacteria and fungi
green manure
type of organic fertilizer consisting of freshly cut or growing vegetation that is plowed into the soil to increase organic matter and humus
compost
type of organic fertilizer that is produced when microorganisms break down leaves, food wastes, paper, and wood
crop rotation
reduces nutrient depletion by alternating heavy nutrient users (corn, cotton, tobacco) with nutrient producers (legumes with nitrogen-fixing bacteria)
inorganic fertilizer
produced from various minerals such as phosphorus, nitrogen, and potassium. Increase productivity but also increases erosion, pollution, eutrophication
food security
every person in a given area has daily access to enough nutritious food
macronutrients
carbohydrates, proteins, fats: needed in higher amounts
micronutrients
vitamins and minerals: needed in small amounts
chronic undernutrition
occurs when people cannot grow or buy enough food to adequately nourish themselves. Consequences: mental retardation, stunted growth, susceptibility to diseases
malnutrition
occurs from low-protein diets that are common in countries where subsistence farming is the most common method of food production
famine
prolonged shortage of food for a country or region. Natural causes: droughts, flood, natural disasters. Social causes: war, political unrest, economic chaos, crop failure. Consequence: violence, increase in disease and mortality rate
industrial agriculture
relies on fossil fuels, pesticides, and fertilizers to produce monocultures and livestock for sale
plantation agriculture
a form of industrial agriculture used in developing countries, focused on cash crops for exports
traditional agriculture
relies more on human labor than machinery, less input of fertilizer and pesticide, focus on polycultures
subsistence
only growing enough to feed your family
overnutrition
food intake exceeds energy use and builds excess body fat. causes heart attack, lower life expectancy
agribusiness
multinational corporations that own huge amounts of land and usually produce monocultures. adv: higher short-term production, more profits and jobs for corporation; dis: loss of jobs for farmers, fossil fuel use, animal waste/pesticide/fertilizer
polyculture
different plants are planted together. adv: crop mature and harvested at different times, provides food throughout year, prevent erosion, less fertilizer and water and pesticides
polyvarietal cultivation
type of polyculture. planting several genetic varieties
intercropping
type of polyculture. two or more different crops grown at the same time in a plot
agroforestry
type of polyculture. crops and trees are grown together
interplanting
type of polyculture. involves growing several crops on the same land simultaneously
overshoot
when resources demands are greater than available resources. (going over the carrying capacity) consequence: deforestation, desertification, war over resources
ecological footprint
uses yields of primary products (from cropland, forest, grazing land and fisheries to calculate the area necessary to support a given activity
green revolution
a shift in the method of agriculture that has resulted in an 88% increase in food production since 1950. based on using high-input (fertilizer, water, pesticide) agriculture to get the same amount of land to produce more food
advantages of genetic engineering
1) less time and cost than traditional cross-breeding 2) more options for organisms 3) disease and pest resistant 4) higher crop yield to reduce hunger 4) advanced tissue cultures - produces on desired parts of organisms
disadvantages of genetic engineering
1) loss of genetic diversity 2) brand ownership 3) cross pollination 4) lack of testing 5) health effects
pest
any species that compete with humans or other organisms or other organisms for food, destroys goods and resources, spreads disease, or invades ecosystems
insecticide
kill insects by clogging airways, disrupting nerves and muscles, prevent reproduction
herbicides
kill weeds by disrupting metabolism and growth
first-generation pesticides
botanical chemicals that are derived from plants that evolved the pesticide toxin as a natural defense
second-generation pesticides
synthesizing plant-based toxins and making them more refined and potent, or using other chemicals agents (come derived from nerve gas) to kill pests
chlorinated hyrdrocarbons
DDT, very persistent and fat-soluble, meaning they bioaccumulate. (worst neurotoxin)
organophosphates
break down faster than chlorinated hydrocarbons but are far more toxic for short-term contact. ex: malathion, parathion. mos common used insecticide in US
bioaccumulation
metabolized into the tissue of everything that it comes in contact with
broad spectrum
pesticides that are toxic to many species. more common
narrow-spectrum
pesticides that are targested to specific species or small groups of organisms. better than broad
advantages of synthetic pesticides
saves lives through disease prevention, increase food supply, profitable from food supply, work well
disadvantages of synthetic pesticides
promote genetic resistance-pest breed too fast, financial issues through time (farmers), kill natural predators, persistant in the environment, toxic
food quality protection act
passed in 1996 due to growing scientific evidence of pesticide effects on children. EPA must reduce allowed levels of pesticide residues in food when evidence that pesticide is harmful
Federal insecticide, fungicide, rodenticide act (FIFRA)
EPA supposed to asses health risks of active ingredients of pesticides in use. (include DDT that was banned)
USDA Organic Program
certifies food according to a list of rules, substances that are allowed/not allowed, labeling of foods, reporting violations, and standards on maintaining land
Organic Foods Production Act of 1990
organic" foods and farming defined by OFPA. can be identified by USDA organic seal
sustainable organic agriculture
high yield polyculture, organic fertilizer, biological pest control, efficient irrigation, crop rotation
organic farming
improves soil fertility, reduce soil erosion, retains more water during drought years, lowers CO2 emissions, reduces water pollution, increases biodiversity
DDT
chlorinated hydrocarbons, used in WW2 to control malaria. BUT disrupts calcium absorption in bird embryos --> weak eggshells