environmental science chapter 15 review arable land – able to grow crops soil formation...
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Environmental Science Chapter 15 Review
Arable land – able to grow cropsSoil formation –involves bedrock decompositionTopsoil – upper layer of soil
- rock particles, water, air, organic matterYield – amount of a crop per hectare (acre)Soil erosion (fields) – caused by farm machineryDesertified farmland
-domestic animals overgraze the land-too many crops are grown/looses fertility-as a result of erosion
Environmental Science Chapter 15 Review
Irrigation water usually comes from rivers & groundwater.
Salinization – accumulation of salts in the soil caused by irrigation & low rainfall
Using rainwater instead of groundwater on crops reduces soil salinization.
Using strips of vegetation in between plowed land reduces soil loss caused by wind & water.
Environmental Science Chapter 15 Review
No-till farming – seeds planted among roots of previous crop.
Livestock – cattle, goats, pigs, sheep, chickensRuminants – cud-chewing mammals
Wheat requires less energy than cattle or cows.
Modern Agricultural methods use plowing machines, drip irrigation systems, and chemical fertilizers.
Environmental Science Chapter 15 Review
DDT harmful to environment-does not break down easily in environment-causes some birds to lay thin shelled eggs-concentrates in animal bodies
(persistent pesticides)
Pest - organism that occurs where it is not wanted - can become resistant to pesticides
Environmental Science Chapter 15 Review
Integrated pest management – chemical, biological & farming methods
Food production has not been increasing as fast as the human population – many go hungry
Famine – widespread food shortage
Malnutrition – health problem due to not eating necessary nutrients
Environmental Science Chapter 15 Review
Humans need 8 essential amino acids from the proteins they eat.
Carbohydrates supply energy for the body.
Lipids (fats & oils) help form membranes/hormones.
Environmental Science Chapter 15 Review
Aquaculture- raising of aquatic organisms for human use – reduce seafood overharvesting
No fishing zones – reduce effects of overharvesting
Genetic Engineering – desirable traits transferred
Environmental Science Chapter 15 Review
Living organisms maintain soil fertility-fungi, bacteria, microorganisms decompose dead plants/animals/excrement
-certain bacteria convert atmospheric nitrogen into forms plants can use.
-earthworms, insects, small animals break up soil, letting in water/air.
Environmental Science Chapter 15 Review
Reducing water erosion of farmland-mixing in stems, roots from previous crops
-loosens topsoil so water soaks in/not run off-worms attracted to this organic material
-aerate topsoil so water soaks in/not run off-contour plowing stops water running downhill
Environmental Science Chapter 15 Review
Biological insecticides (bacteria, reproductive-interfering agents) - target pests but do not harm others.
Chemical insecticides can persist or build up and then harm other species which feed on the insects.
Environmental Science Chapter 15 Review
Erosion in farming- only recently a serious problem (modern
machinery & practices)- previous farmers did not leave bare soil
exposed in huge fields- small fields & gardens = less runoff- practiced crop rotation- fields allowed to lie fallow every few seasons
Environmental Science Chapter 15 Review
Explain how pests develop a resistance to pesticides.
Word bank = aquaculture, famine, genetic engineering, livestock, malnutrition, meat, overharvesting, pest, ruminants, salinization, topsoil, yield.