Exam 2

Question 1

impacts of soil compaction on soil health

Answer 1

1. Less nutrient and water uptake by plants
2. Less environment for helpful biota in soil
3. Less water retention in soil (runoff)
4. More soil erosion
5. Slower breakdown of organic matter
6. Since plant roots cant get as far down, its harder to break up soil and nutrients are stuck down deep

Question 2

Sodic and saline soils

Answer 2

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.

Question 3

Other conraminants in soil and impact

Answer 3

Heavy metals-change pH and/or poison biota

Pesticides-impacts on animals and changes soil pH sue to chemicals

Question 4

Changing of nutrient cycles with larger ag

Answer 4

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.

Question 5

Ecosystem services provided by healthy soil

Answer 5

1. Water retention-preventing floods
2. Growth of plants/crops
3. Environment for biota
4. Prevention of erosion
5. Recreation
6. Grazing land for animals and wildlife habitat

Question 6

Soil biota community

Answer 6

Earthworms-break down organic matter into humus 
Bacteria-break down nutrients into forms available to plants
Predatory biota (mites, spiders, etc)-control pest populations

Question 7

Role of bacteria and fungi in N cycle

Answer 7

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.

Question 8

Carrying capacity K

Answer 8

Amount of a particular kind of livestock that a certain area can handle without beinf overgrazed

Question 9

Continuous grazing

Answer 9

Cattle graze throughout the grazing season

Question 10

Rotational Grazing

Answer 10

Use of fences to allow livestock to only graze certain areas at a time

Question 11

Deferred Grazing

Answer 11

Delaying the start of grazing beyond the normal beginning of grazing period

Question 12

9 recommended practices to imcrease grazing efficiency

Answer 12

1. Seed improved cultivars (natives)
2. Delay spring grazing until grass has hood start (deferred)
3. Graze cattle and sheep simultaneously
4. Adjust stocking rate to grass growth rate
5. Leave 50% of forage for reserve and residue
6. Integrate range with irrigated pasture grazing
7. Practice rotational and deferred grazing
8. Move salt periodically to undergrazed areas away from water
9. Clear brush to encourage growth of forage grasses

Question 13

What agency manages most of rangelands and forests in US?

Answer 13

US Forest Service

Question 14

Legislation for rangeland management

Answer 14

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

Question 15

Where is most deforestation happening

Answer 15

In the rainforests (Amazon)