Mainly water and wind.;Human: construction, off roading, tilling, mining, etc
Global Soil Loss?
Lost about 15% of land for agriculture due to soil erosion
Desertification;
Turning productive (fertile) soil into less productive soil-overgrazing-desforestation
Salination
Fields must be repeatedly flushed with fresh water to remove salt build up
Water Logging
Plants are over saturatedreducing yield
Sulfur Cycle
SO2 ( volcanos)Burning coalComes out of decaying materialReacts in atmosphere to create hydrogen sulfate (H2SO4), sulfuric acid (acid rain);Human Effects: refining sulfur containing petrol
Phosphorus Cycle
Very slowLimiting factor for plant growthMine phosphate out of rock and add it to fertilizers and detergents;Human EffectsWe add excess phosphates from runoff of animal wastes and fertilizers
Dead Zone (Anoxic Zones)
Anoxic: no O2;Nutrients cause an algal bloom ;– lots of algaeToo much algae grows on the surface; it blocks out lights, plants dieThen algae start to die and start to decomposeBacteria that do decomposition require O2O2 runs out, dish die, the plants are dead
Nitrogen Cycle
Nitrogen in air (N2)N2 fixation by bacteria to ammoniaNitrification by bacteria to nitrate (NO2-)Then to Nitrate (NO3-)Denitrification of nitrate (NO3-) by bacteriaback into Nitrogen Gas (N2) Atmosphere Effects of HumansAdding Nitrous Oxide (N2O) to the atmosphere can warm the atmospherecontaminate groun water from nitrate ions in inorganic fertilizers
Legumes
Contains N2 ficing bacteria in their roots that can provide nitrates for the plants
Carbon Cycle
Atmosphere (CO2)Photosynthesis/respirationLimestone (CaCO3) Effects from humansBurning fossil fuelsclearing vegetation
Water Cycle (Hydrologic Cycle)
Evaporation/transpiration-> plant sweatingCondensationPrecipitationInfiltration-> enters soilPercolation -> H2O moves through soil Effects of Human Withdrawing large amounts of fresh waterPolluting surfance and underground water
