15 terms

Plant Biology Final Exam: Environment and Agriculture

current agricultural practices
-new crop varieties
-chemical fertilizers
-chemical pesticides
-chemical herbicides
green revolution
introduction of scientifically developed food crops that can produce high yields
-prevented starvation, but method destroyed future food production
environmental impact of agriculture
1) declining biodiversity
2) soil erosion
3) salinization
4) desertification
5) chemical fertilizers
6) pesticides
declining biodiversity
-farmers only use a few varieties for crops
-domesticated crops have less genetic diversity
-selective breeding leads to crop uniformity
-result= disease vulnerability, pests evolve quicker
soil erosion
loss of soil from tilling (plowing) and wind/water effects
-soil= organic (topsoil) and inorganic matter
-topsoil is lost, leaving subsoil
-solutions= less plowing, no-till agriculture, more perennials, less annual plants
salt build-up in soil due to irrigation
-salt can kill plants (as water evaporates, salt builds up)
-solutions= new irrigation system that delivers water directly to roots, adding water to salt-damaged land
expansion of desert into cropland
-causes= overgrazing, improper irrigation, deforestation
-solutions= drought-tolerant plants, retiring the land
chemical fertilizers
excessive use of chemical fertilizers
-decreases organic matter in soil
-leads to fertilizer pollution in soil
-solution= organic fertilizers, crop rotation with leguminous crops (nitrogen fixation)
chemicals used to control insects, bacteria, fungi,etc
~insects are becoming resistant to pesticides
~untested for health effects
~leads to pollution of soil and water
~disrupts food chains
~biological control (using organisms to eat the insects)
~combining chemical pesticides and biological control only when necessary
carrying capacity
maximum number of organisms that can be supported in a habitat
developed vs. developing countries
-developed countries have overnourishment
-developing countries have under/malnourishment (poverty is main cause of malnourishment)
genetic diversity
-wild populations have more genetic diversity
-domesticated populations have less genetic diversity
staple food from south america that is high in protein and carbs
winged bean
plant from asia, all parts of the plant are edible (leaves, tendrils, flower, root, seeds)
staple food in central america that is very high in protein