Download 22 Problems on Different Types of Soil | SSC 010 and more Exams Agricultural engineering in PDF only on Docsity! Soil Science 10 Midterm Exam #2 (2002) Mark each statement true or false. Each correct answer is worth 2 points (20 points total). 1. Soil water always flows from regions of high matric potential (ψm) to regions of low matric potential (ψm). 2. The unsaturated hydraulic conductivity of a soil will be greater at field capacity than at permanent wilting point (PWP). 3. Mineralization refers to the process that results in the conversion of an element from an organically bound form to an inorganic form as a result of microbial decomposition. 4. 2:1 layer silicate clays contain one tetrahedral layer sandwiched between two octahedral layers. 5. The primary driving force for saturated water flow through soils is gravity. 6. Soil organic matter concentrations will generally be greater in a grassland soil than in a forest soil, everything else being equal. 7. A sandy loam with 20% moisture content will have a lower matric potential than a clay loam with 20% moisture content. 8. Selectivity (i.e., the affinity) of cations for cation exchange sites depends more on the hydrated size of the cation than on the cation charge. 9. The dominant form of cation exchange capacity (CEC) on humus is pH dependent charge. 10. The addition of lime (CaCO3) will result in a decrease in base saturation of a soil. 2 Points (4) 11. Spilling excess fertilizer on a lawn can result in “burning” of your grass, even if you have recently irrigated your lawn. The burning of the grass results from the inability of the grass to extract sufficient water from the soil. How can you explain the inability of the grass to take up water in these burned patches? (6) 12. On the graph below, draw a line that describes how the decomposition rate of organic matter varies as a function of soil water content. Provide a brief explanation for why you drew the line as you did. (4) 13. Briefly explain why is the center of a compost pile hot? Water Content D ec om po si tio n R at e Low Medium High Low High
