Chap. 3 Range M.

Question 1

What mountain range causes the rain shadow is Rexburg?

Answer 1

The Sierra-Nevada or Cascade Mountains

Question 2

Annual Variation in Precipitation

Answer 2

–Variability in precipitation increases rapidly as the annual total drops below 18 inches (450 mm). This greatly increases variability in forage production.

–Forage production is much more erratic from year to year in desert areas than in prairie areas. This increases ranching risk and reduces profitability in desert compared to prairie areas.

Question 3

Drought

Answer 3

**75% or less of the average annual growing season precipitation
- Intensity and duration determine its severity
-Some plant species may benefit from drought (deep rooted shrubs) due to reduced competition
•Shallow rooted species such as grasses often die

Question 4

***Factors Determining Precipitation Effectiveness

Answer 4

Intensity and duration—soil texture, slope, plant cover
B. Distribution—season
C. Wind—increases evaporation
D. Temperature—high temperature increases evaporation
E. Relative Humidity—higher the relative humidity, more precipitation
F. Form of precipitation—rain versus snow

Question 5

Snow

Answer 5

• until it melts
• May extend period of available soil moisture
• Lost from area by:
  1. Runoff
  2. Evaporationk
  3. Sublimation

Question 6

Plains

Answer 6

• Dry winters, wet summers, moderate total precipitation (10-35 inches annual ppt), grassland.

Question 7

Pacific

Answer 7

• Wet winters, dry summers, moderate to high total precipitation (15-50 inches annual ppt), cool season herbaceous species.

Question 8

Southwestern

Answer 8

– Bimodal precipitation (winter and summer), low to moderate total precipitation (5-18 inches annual ppt), cactus and creosote.

Question 9

Great Basin

Answer 9

• Wet winter and spring, dry summers, low total precipitation (4-16 inches annual ppt), sagebrush and juniper.

Question 10

Eastern

Answer 10

• Even distribution of precipitation throughout year, high total precipitation (35-55 inches annual ppt), deciduous trees.

Question 11

Florida

Answer 11

• Summer peak in precipitation but wet all year (50-70 inches annual ppt).

Question 12

Topography

Answer 12

•refers to the relief (slope) features of a land area.
–Wide differences in topography between the eastern and western United States largely explain differences in climate and vegetation.
–Aspect of slopes has considerable influence on the vegetation and their use by grazing animals.

Question 13

South-facing slopes support what type of climate?

Answer 13

support grassland and are best used in the spring.

Question 14

North-facing slopes support what type of climate?

Answer 14

are best used in summer because there is more shade, and forage species are less advanced in growth.

Question 15

Precipitation

Answer 15

is the most important single factor determining the type and productivity of vegetation in an area.

• forage production increases rapidly as precipitation increases up to 20inches(500mm) per year.
• Above 20 inches of precipitation per year, soil characteristics can assume greater importance than precipitation in determining forage production.

Question 16

Soil

Answer 16

•Dynamic natural body in which plants grow, composed of mineral and organic materials and living forms.
•The most serious consequence of sustained overgrazing is loss of soil.
–⭐️1000 years is typically required for natural formation of 1 inch of soil. However, 1 inch of soil can be lost within a couple of years of severe overgrazing.

Question 17

Soil Texture

Answer 17

Size of mineral particles in the soil.

   a. Rock
   b. Gravel
   c. Sand
   d. Silt
   e. Clay

Question 18

What determines the capacity of soil to hold water?

Answer 18

The water-holding capacity of soil increases as particle size decreases because water clings to surfaces, and small particles have relatively the most surface.

Question 19

What determines soil texture?

Answer 19

Soil texture designation based on percentages of sand, silt, and clay

Question 20

Soil Structure

Answer 20

Refers to how soil particles are arranged
–Important because it allows water to enter soil and affects soil capability to store water.

–Soils having a granular structure are most productive for farming and grazing because they optimize water infiltration and storage.

Question 21

What soil factors affect rangeland productivity?

Answer 21

1. Fertility
   
   2. Texture
   3. Structure
   4. pH
   5. Depth
   6. Organic matter

Question 22

Draw a precipitation pattern in —– area?

Answer 22

Pg 37 top map

Question 23

What are the categories for soil?

Answer 23

Entisols – Rocky Mountains, youngest soil order
•Aridisols – Southwest desert, often dry
•Gelisols – Tundra soils covered with snow and ice
•Mollisols – Grassland and prairies, high organic matter
•Alfisols – Similar to mollisols but more leached
•Ultisols – Southeast, highly leached
•Oxisols – Hawaii and Puerto Rico, most intensively leached

Question 24

Desertification

Answer 24

formation of desert like conditions largely through human actions in areas that do not have desert climates.  Sahel Region of Africa and China
•Uncontrolled livestock grazing
•Burning vegetation
•Cutting wood
•Temporary cultivation
•Abandonment of semi-arid to arid lands

Question 25

What three things determine the potential for a range to support livestock and wildlife?

Answer 25

The interaction among climate, soil, and topography

Question 26

Important Principles

Answer 26

* Precipitation is the most important factor determining the type and productivity of vegetation in an area. * Differences in amount, timing, and frequency of precipitation among rangeland types necessitate different management strategies. * Soil is the primary factor determining forage production within a particular climate. * A critical part of range management is to maintain enough vegetation cover to protect the soil profile.

Question 27

Aspect

Answer 27

refers to the directional orientation of slopes.