SCSC 301 TEST QUESTIONS AND ANSWERS

SCSC 301 TEST QUESTIONS AND ANSWERS Which horizon is not part of the soil solum? - ANSWER- C Organic matter in soil typically accounts for ____% or less of the soils total volume. - ANSWER- 5% Pore space in soil may contain either _____ or _____ - ANSWER- Air Water Soils are the result of ______ and biota acting on parent material over time as modified by ______ - ANSWER- Climate Topography Though plants depend on soil for growth, which of the items below is found in soil, but not required for plant growth? - ANSWER- Carbon dioxide Soil profile - ANSWER- Contains 5 master horizons potentially founding a soil A->E->B->C Which soil forming factor can be transported before it affects soil formation? - ANSWER- Parent material Which of the following describes a composite sample? - ANSWER- 10 samples of soil were collected across a field, mixed together, then used as the final single soil sample representing the field submitted for analysis Which horizon is most affected by the soil forming factors? - ANSWER- A Which of the following are soil forming factors? - ANSWER- Time Parent material Topography Biota Climate Compare a humid tropical rainforest to a cool and dry mountain plain and elect the most correct answer. - ANSWER- The humid tropical rainforest will weather faster and the soil will develop more rapidly due to intense weathering climate Soil that forms in place is called _____? - ANSWER- Residual Soils that have parent materials affected by the movement of water include _____ soils, which are formed from deposition of sediments from streams and rivers into deltas and floodplains, and _____ soils, which are formed from deposition of sediment by lakes. - ANSWER- Alluvial Lacustrine A mineral, such as quartz, that has not been altered since its formation from magma is a _____ mineral. - ANSWER- Primary Which of the following are primary minerals? - ANSWER- Mica Quartz Olivine Hornblende Feldspar As a primary mineral weather to form secondary minerals, elements can sometimes be lost. Which of the following are most likely to be lost to leaching? - ANSWER- Calcium (Ca) Potassium (K) Sodium (Na) Soil organic matter forms from the decomposition of _____ - ANSWER- Animal residue Manure Microorganism residue Plant residue By volume, soil is made up of which of the following? - ANSWER- Mineral matter Air Water Organic matter Organic matter is made of carbon compounds. When it decomposes, what gas forms? - ANSWER- Carbon dioxide (C02) Another word for soil organic matter is _____ - ANSWER- Humus The color of soil organic matter is ____, which also influences the color of surface soils. - ANSWER- Dark brown to black Which primary mineral is relatively resistant to weathering and does not weather into another mineral? - ANSWER- Quartz Horizons - ANSWER- O,A,E,B,C Soil Solum - ANSWER- O,A,E,B Regolith - ANSWER- C Topsoil vs. subsoil - ANSWER- TOP- More affect from soil forming factors (darker, more organisms) & usually more porous, smaller aggregates, less clay and more sand/silt Topsoil vs. subsoil - ANSWER- SUB- Less affect from soil forming factors (lighter in color, fewer organism) & usually less porous ( more compacted) larger aggregates, more clay Pedon - ANSWER- Smallest 3D unit of soil with all the soil characteristics Polypedon - ANSWER- Group of smaller pedons 4 major soil components - ANSWER- Solids- Mineral matter (~45%) Organic matter (~5%) Pore space- Air (25%) Water (25%) Sand particles - ANSWER- Largest, low affinity for water, nutrients and each other Silt particles - ANSWER- Medium sized, moderate affinity for water, nutrients and each other, low affinity for nutrients Clay particles - ANSWER- Smallest (largest surface area) High affinity for water, nutrients and each other Tends to aggregate Can act as a colloid