Briefly describe the structural differences between hematite and goethite. Why does climate affect the relative amounts of these two minerals in soils?
- Briefly describe the structural differences between hematite and goethite. Why does climate affect the relative amounts of these two minerals in soils? (5 pts)
- Describe how the surface charge characteristics of hydrous oxides and 2:1 layered phyllosilicates differ. (5 pts)
- Exactly why would kaolinite make a better sorbent for nonpolar organic molecules than smectite or vermiculite? (5 pts)
- Why is it difficult to accurately determine weathering rates in soils? (5 pts)
- Describe the general weathering scheme of muscovite to dioctahedral vermiculite. (5 pts)
- Calculate the activities coefficients for Al3+ and K+ in a soil solution in which they are each 1 mmolar (10-3 molar) and the balancing anion is SO4-2. Show your work. Why are they so different? (5 pts)
- Phosphorus is not a macronutrient and there should be plenty of total P in most soils. Why is often necessary to add more P to obtain optimum plant growth? (5 pts)
- You’ve had a garden for a number of years and have added dairy manure compost to provide nitrogen. Now your soil test is ‘excessive’ in phosphorus. Is this a problem for your garden plants; for your local water body; for your self esteem? What should you do about it? What form of phosphorus is your soil test measuring? (10 pts)
