impacts of soil compaction on soil health
- Less nutrient and water uptake by plants
- Less environment for helpful biota in soil
- Less water retention in soil (runoff)
- More soil erosion
- Slower breakdown of organic matter
- Since plant roots cant get as far down, its harder to break up soil and nutrients are stuck down deep
Sodic and saline soils
High in salts and/or saline. Caused by road salting, construction, and irrigation without much rainfall (arid climates). This impacts soil health by lessening the uptake of water and making soil more susceptible to erosion.
Other conraminants in soil and impact
Heavy metals-change pH and/or poison biota
Pesticides-impacts on animals and changes soil pH sue to chemicals
Changing of nutrient cycles with larger ag
Naturally, nutrients stay localized, but with large ag fertilizers are brought in from far away, taking the nutriwnts from one place and concentrating them in farmland, leading to potwntial runoff and eutrophication of waterways.
Ecosystem services provided by healthy soil
- Water retention-preventing floods
- Growth of plants/crops
- Environment for biota
- Prevention of erosion
- Recreation
- Grazing land for animals and wildlife habitat
Soil biota community
Earthworms-break down organic matter into humus Bacteria-break down nutrients into forms available to plants Predatory biota (mites, spiders, etc)-control pest populations
Role of bacteria and fungi in N cycle
Bacteria and fungi break down organic matter into forms available for plant life, which can then grow to ecentually produce more organic matter to be broken down.
Carrying capacity K
Amount of a particular kind of livestock that a certain area can handle without beinf overgrazed
Continuous grazing
Cattle graze throughout the grazing season
Rotational Grazing
Use of fences to allow livestock to only graze certain areas at a time
Deferred Grazing
Delaying the start of grazing beyond the normal beginning of grazing period
9 recommended practices to imcrease grazing efficiency
- Seed improved cultivars (natives)
- Delay spring grazing until grass has hood start (deferred)
- Graze cattle and sheep simultaneously
- Adjust stocking rate to grass growth rate
- Leave 50% of forage for reserve and residue
- Integrate range with irrigated pasture grazing
- Practice rotational and deferred grazing
- Move salt periodically to undergrazed areas away from water
- Clear brush to encourage growth of forage grasses
What agency manages most of rangelands and forests in US?
US Forest Service
Legislation for rangeland management
Homestead act-160 acres (not enough for arid western soils and quickly deteriorated-dust bowl)
Taylor Grazing Control Act-1) halt overgrazing 2) improve and maintain ranges 3) stabilize rangeland economy (Bureau of Land Management)
Fed. Land Policy and Mgmt Act-broadened BLM power
Food Security Act of 1985-removal of erodable rangeland for 10 yr periods during which farmers get ‘rent’ payments
Where is most deforestation happening
In the rainforests (Amazon)
