SCSC 301 TAMU Exam 2 Howe Questions With Complete Solutions

Which of the following is NOT a carbon-containing compound that is involved in the cycling of carbon associated with most plant/animal life forms? correct answer: Calcium carbonate Which organic matter property affects the availability of nutrients to plants? correct answer: Cation exchange capacity Complete degradation of residues (complete oxidation) results in correct answer: CO2 Which of the answers below represents an immobilized form of N? correct answer: Protein in a bacterial cell Which is true when comparing aerobic vs anaerobic organic matter decomposition? correct answer: Anaerobic degradation is much slower than aerobic and results in compounds that are partially decomposed Soil organic matter degradation will be greatest when correct answer: There is sufficient soil moisture and aeration at neutral pH and relatively warm temperatures to degrade residue with high levels of N Organic matter tends to decrease the ___ of soils. correct answer: Bulk density ___ is the element in residue that has the greatest effect on the rate of residue decomposition. correct answer: Nitrogen The organic matter content of soils tends to decrease with increasing frequency of: correct answer: Cultivation A soil with C/N ratio of 600:1 could be a material such as correct answer: Sawdust or leaves that have a low N content and a high potential for N immobilization Poorly defined organic substances that are complex, resistant to decay, and polymeric are correct answer: Humic substances Which of the following could be used to improve soil organic matter in a cropping system? correct answer: Reduce the plant materials that are harvested and return any residues back to the field If you had to guess, which environment would likely have the greatest soil organic matter? correct answer: Northeast US Available water in soils is water held between the wilting coefficient and correct answer: Field capacity