Lecture 2: Physical Characteristics Flashcards
Precipitation
Single most important factor in determining type and productivity of vegetation in an area (more importance >500mm ppt)
Orographic influences
Precipitation distribution is impacted by topography and distance from oceans. Rain shadow on leeward side,
Topography: aspect
Directional orientation of slopes
Topography: degree of slope
Affects vegetation productivity and use by range animals. Increases precipitation runoff, as slop increases, vegetation decreases
Soils
Second most important factor limiting plant production
Soil factors:
- Texture
- Structure
- Depth
- PH
- Organic content
- Fertility
Grassland precipitation
Low amounts, between 250-500mm for most temperate grasslands
Soil texture
Changes the rooting abilities of plants, and their ability to hold nutrients, water infiltration rates, and susceptibility to erosion. Can be clay, silt, sand, gravel, and rock sized.
Small texture holds tear and nutrients more, but less penetration, which can impact filtration rate
Soil depth
Deeper soils will be more productive and more suitable for production. Soil heterogeneity can promote plant species diversity
Soil pH
More acidic with more rain, more basic with less rain. Basic has calcium carb, pH affects what minerals are present. If too acidic, can decrease productivity
Soil organic content
Material dies off every fall and winter, which increases organic material. This increases the moisture it can hold, binds the soil, releases nutrients, and combines nutrients, this working to increase productivity
Soil fertility
N is usually most limiting especially in younger areas. P is limiting in older areas. Fertility increases productivity, because if has organic matter, nutrient turnover, and water holding capacity.
Soil salinity
Salt affects ability to uptake water and nutrients. It is energy using in plants and will decrease productivity. Must be specialized for saline conditions
