Soil Composition and Properties - AP Environmental Science
- Identify the soil particle with the smallest size.
- Clay. Diameter less than 0.002mm with high surface area for retention.
- What is the effect of organic amendments on soil?
- Improve structure, fertility, and microbial activity. Add nutrients and beneficial organisms to enhance growth.
- What are the three primary soil particles by size?
- Sand, silt, and clay. Categorized by decreasing particle diameter from largest to smallest.
- What is the effect of soil compaction on plant growth?
- Reduces root penetration and water infiltration. Compressed particles decrease pore space for growth.
- What is the soil texture triangle used for?
- To classify soil texture based on particle size. Determines proportions of sand, silt, and clay in soil samples.
- What is the effect of high soil pH on nutrient availability?
- Decreases availability of some nutrients. Iron and phosphorus become less soluble in basic conditions.
- Which soil type has the fastest drainage?
- Sand. Large pore spaces between particles allow rapid water movement.
- What is soil fertility?
- Ability of soil to provide nutrients for plant growth. Combination of physical, chemical, and biological factors.
- What is the primary mineral component of clay?
- Silicates. Layered aluminum and silicon structures provide stability.
- Identify the process of water movement through soil.
- Percolation. Gravity-driven downward flow through soil layers.
- What does soil texture affect?
- Water retention, permeability, and workability. Particle size distribution determines physical behavior.
- Identify the soil horizon rich in organic material.
- O Horizon. Surface layer of fresh leaf litter and decomposing material.
- What is the primary component of mineral soil?
- Inorganic material. Weathered rock fragments provide structure and nutrients.
- What is the main consequence of soil degradation?
- Decreased agricultural productivity. Loss of soil quality threatens food security worldwide.
- What is soil porosity?
- The volume of pores or spaces in soil. Determines water storage capacity and gas exchange in soil.
- What is the purpose of soil conservation?
- Prevent soil erosion and degradation. Maintains productive agricultural land for future generations.
- Identify the process of converting organic waste into humus.
- Composting. Aerobic decomposition creates stable organic matter.
- Which soil type has equal parts of sand, silt, and clay?
- Loam. Approximately equal proportions create ideal agricultural conditions.
- What is the pH range of basic soil?
- pH greater than 7. High hydroxide ion concentration can limit phosphorus uptake.
- What is the role of earthworms in soil health?
- Aerate soil and decompose organic matter. Create channels and mix organic matter throughout profile.
- What is soil permeability?
- The ability of soil to transmit water and air. Controlled by pore size and connectivity between particles.
- How does vegetation affect soil erosion?
- Reduces erosion by stabilizing soil. Root systems bind particles and slow water runoff.
- Identify the soil horizon known as the topsoil.
- A Horizon. Contains mixture of organic matter and weathered minerals.
- What is soil salinization?
- Accumulation of soluble salts in soil. High salt content inhibits plant water uptake.
- How does pH affect soil microbial activity?
- Microbial activity is optimal near neutral pH. Extreme pH values reduce enzyme function and diversity.
- What is the effect of soil erosion on fertility?
- Reduces fertility by removing topsoil. Loss of nutrient-rich surface layer reduces productivity.
- Which soil type is best for agriculture?
- Loam. Balanced mixture provides optimal drainage and retention.
- What is the cation exchange capacity (CEC)?
- Ability of soil to hold and exchange cations. Measures soil's ability to retain essential plant nutrients.
- Which soil type has the highest water retention?
- Clay. Small particle size and high surface area retain more water.
- Identify the soil particle with the largest size.
- Sand. Diameter ranges from 0.05-2.0mm, allowing rapid water drainage.
- What is the pH range of acidic soil?
- pH less than 7. High hydrogen ion concentration affects nutrient availability.
- Identify the soil layer where roots primarily grow.
- A Horizon. Zone of maximum biological activity and nutrient concentration.
- What is humus?
- Decayed organic matter in soil. Forms from decomposition by bacteria and fungi over time.
- What is the role of soil microorganisms?
- Decompose organic matter. Break down dead material into nutrients plants can absorb.
- What role does organic matter play in soil?
- Improves fertility and structure. Increases cation exchange capacity and water holding ability.
- What is the importance of soil structure?
- Influences water and air movement, root growth. Arrangement of particles affects physical properties.
- What is the B Horizon also known as?
- Subsoil. Accumulation zone for leached minerals from upper layers.
- Which soil property affects nutrient availability?
- Soil pH. Controls solubility and uptake of essential minerals.
- What is the primary factor in determining soil color?
- Organic matter content and mineral composition. Dark colors indicate high organic content and iron oxides.
- What is the main cause of soil acidification?
- Excessive rainfall leaching away basic ions. Natural process in high-rainfall regions removes base cations.