Precipitation
Precipitation 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 20 inches (500 mm) per year.
-Above 20 inches of precipitation per year, soil characteristics can assume greater importance than precipitation in determining forage production.
| Term | Definition |
|---|---|
Precipitation | Precipitation 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 20 inches (500 mm) per year.
-Above 20 inches of precipitation per year, soil characteristics can assume greater importance than precipitation in determining forage production.
|
Kansas forage production (pounds/acres), stocking rate (acres/animal unit), annual ppt (inches) | 4,100
3-4
33 |
South Dakota forage production (pounds/acres), stocking rate (acres/animal unit), annual ppt (inches) | 2,100
7-10
14 |
Colorado forage production (pounds/acres), stocking rate (acres/animal unit), annual ppt (inches) | 750
28-32
12 |
New Mexico forage production (pounds/acres), stocking rate (acres/animal unit), annual ppt (inches) | 276
73-85
8 |
Nevada forage production (pounds/acres), stocking rate (acres/animal unit), annual ppt (inches) | 78
265-300
5 |
Drought | Drought – 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
|
Climatic types in the USA | (Left to right) Pacific, Great Basin, Southwestern, Plains, Eastern, Florida |
Plains | Dry winters, wet summers, moderate total precipitation (10-35 inches annual ppt), grassland |
Pacific | Wet winters, dry summers, moderate to high total precipitation (15-50 inches annual ppt), cool season herbaceous species |
Southwestern | Bimodal precipitation (winter and summer), low to moderate total precipitation (5-18 inches annual ppt), cactus and creosote. |
Great Basin | Wet winter and spring, dry summers, low total precipitation (4-16 inches annual ppt), sagebrush and juniper |
Eastern | Even distribution of precipitation throughout year, high total precipitation (35-55 inches annual ppt), deciduous trees. |
Florida | Summer peak in precipitation but wet all year (50-70 inches annual ppt) |
Topography | 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 refers to the directional orientation of slopes.
-Aspect of slopes has considerable influence on the vegetation and their use by grazing animals.
|
Soil | Dynamic natural body in which plants grow, composed of mineral and organic materials and living forms |
How long does it take for an inch of soil to naturally form? | 1,000 years |
Layers of soil | A horizon: Dark, rich in humus
B horizon: Light-colored calcium salts
C horizon
--------------
Litter(on top of A horizon)
Topsoil(A horizon)
Decomposed parent material(C horizon)
Bedrock |
Soil texture | Size of mineral particles in the soil
a. Rock
b. Gravel
c. Sand
d. Silt
e. Clay
|
What is the most common soil type in Idaho? | Mollisol |