Examine soil characteristics. Create a two-column chart. In the first column, list “fertility,” “composition,” “resistance to erosion,” and “texture.” Think about how each characteristic is affected by many factors. Explain those factors in the right column.
Soil Characteristic Factors Affecting the Characteristic
Fertility - Nutrient content
- Organic matter content
- pH levels
- Microbial activity
Composition - Mineral content
- Organic matter content
- Texture
- pH levels
Resistance to erosion - Soil structure
- Soil cover
- Slope gradient
- Vegetation cover
Texture - Soil particle size
- Soil structure
- Organic matter content
- Parent material
Explanation of Factors:
1. Fertility:
- Nutrient content: The availability of essential nutrients in the soil depends on factors such as the parent material, weathering processes, nutrient cycling, and fertilization practices.
- Organic matter content: The amount of organic matter in the soil influences its nutrient-holding capacity, water holding capacity, and overall soil structure. It is affected by factors like decomposition rates, vegetation cover, agricultural practices, and management of crop residues.
- pH levels: Soil pH affects the solubility and availability of nutrients. It is influenced by factors like parent material, leaching, acid deposition, and plant root exudation.
- Microbial activity: Soil organisms like bacteria, fungi, and earthworms play a crucial role in nutrient cycling and decomposition of organic matter. Factors such as temperature, moisture levels, presence of organic matter, and chemical inputs can impact microbial activity.
2. Composition:
- Mineral content: The mineral composition of soil is determined by the parent material from which it originated, weathering processes, and the deposition of minerals over time.
- Organic matter content: Similar to fertility, organic matter content shapes the composition of the soil. It contains decomposed plant and animal residues, affecting the nutrient levels and overall fertility of the soil.
- Texture: Soil texture refers to the relative proportion of sand, silt, and clay particles. These particles affect a soil's composition, nutrient-holding capacity, water drainage, and aeration. It is influenced by factors such as weathering, deposition, and erosion processes, as well as parent material.
3. Resistance to erosion:
- Soil structure: A well-aggregated soil structure reduces soil erosion by improving water infiltration and decreasing surface runoff. Soil structure is influenced by factors such as organic matter content, biological activity, irrigation or rainfall patterns, tillage practices, and compaction caused by heavy machinery or foot traffic.
- Soil cover: Vegetation cover, crop residues, or mulching can protect the soil from direct impact of raindrops, wind, and water runoff, reducing erosion rates. It is influenced by farming practices, land management, and vegetation types.
- Slope gradient: Steeper slopes are more prone to erosion as they promote faster surface runoff and increase the velocity of water, carrying away soil particles. Slope gradient is a natural factor influenced by topography and landforms.
- Vegetation cover: Presence of vegetation, both natural or man-made, helps bind soil particles together, protects the soil surface from wind and water erosion, and adds organic matter back into the soil.
4. Texture:
- Soil particle size: The proportion of sand, silt, and clay particles determines the texture of the soil. The size of these particles affects water-holding capacity, nutrient availability, soil structure, and drainage. Particle size is primarily influenced by the parent material and weathering processes.
- Soil structure: The arrangement of soil particles influences the texture, permeability, aeration, and water-holding capacity of the soil. Soil structure is impacted by factors like organic matter content, tillage practices, compaction, and aggregates formed by microbial and root activity.
- Organic matter content: Organic matter improves soil structure by providing binding agents, enhancing soil aggregation, and promoting better water and nutrient retention. The presence of organic matter depends on factors such as vegetation cover, decomposition rates, and management practices.
- Parent material: The mineral composition of the parent material contributes to the texture of the soil. Different parent materials like rocks, sediments, or volcanic ash result in distinctive soil textures.