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Unformatted text preview: Soil Science 10 Midterm Exam #2 Mark each statement true or false. Each correct answer is worth 2 points (20 points total). 1. Due to its chemical structure, lignin will be decomposed by microbes more rapidly than cellulose. 2. Isomorphous substitution in layer silicate clays creates pH dependent charge. 3. Capillary action originates from adhesion and cohesion forces. 4. Hydrogen bonding occurs between the individual units of 2:1 layer silicate clays. 5. Grassland soils tend to have greater concentrations of organic matter than forest soils. 6. Over time, acid rain will decrease the base saturation and pH of a soil. 7. Nitrate (NO 3- ) is more mobile through soils in California as compared to ammonium (NH 4 + ). 8. The plant availability of phosphorus tends to be greatest at pH values greater than 7.0. 9. Tillage of a soil for agriculture typically leads to an increase in concentrations of soil organic matter. 10. A sandy loam with 20% moisture content will have a higher matric potential than a clay loam with 20% moisture content. Points (6) 11. Rank the following soil components based on their relative stability (resistance) to chemical weathering in soils and for their cation exchange capacity. For relative stability: 1 for the highest stability and 3 for the lowest stability; For CEC: 1 for highest and 3 for lowest Soil component Relative Stability...
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- Fall '10
- cation exchange capacity, Humus, CEC, Low nd Sa