Exam 1 A - 35 Questions on Fundamental of Soil Science with Solution | SOIL 2124, Exams of Agricultural engineering

Download Exam 1 A - 35 Questions on Fundamental of Soil Science with Solution | SOIL 2124 and more Exams Agricultural engineering in PDF only on Docsity! Fundamentals of Soil Science [SOIL 2124] Spring 2003 Exam 1A pg. 1 SOIL 2124 EXAM 1A 14 February 2003 All Multiple Choice are 2 points each other questions are as assigned. Use information from the TIFTON SERIES to answer the first 11 questions. The Tifton series consists of very deep, well drained, moderately slowly permeable soils that formed in loamy marine sediments. These soils are on nearly level to gently sloping uplands and have slopes that range from 0 to 8 percent. TAXONOMIC CLASS: Fine-loamy, kaolinitic, thermic Plinthic Kandiudults TYPICAL PEDON: Tifton loamy sand--on a 3 percent convex slope in a pasture. (Colors are for moist soil.) Apc--0 to 11 inches; dark grayish brown (10YR 4/2) loamy sand; weak fine granular structure; very friable; common fine roots; 9 percent ironstone nodules by volume less than 0.75 inches in diameter; moderately acid; clear smooth boundary. (5 to 12 inches thick) Btc1--11 to 22 inches; strong brown (7.5YR 5/8) fine sandy loam; weak fine subangular blocky structure; very friable; common fine roots; few fine pores; sand grains bridged with clay; 11 percent ironstone nodules by volume less than 0.75 inches in diameter; strongly acid; gradual wavy boundary. Btc2--22 to 40 inches; yellowish brown (10YR 5/6) sandy clay loam; weak medium subangular blocky structure; friable; few fine roots; few fine continuous pores; few faint clay films on faces of peds; 10 percent ironstone nodules by volume less than 0.75 inches in diameter; moderately acid; gradual wavy boundary. (Combined thickness of the Btc horizon is 14 to 34 inches) Btv1--40 to 50 inches; yellowish brown (10YR 5/8) sandy clay loam; moderate fine subangular blocky structure; friable; few fine roots; few medium continuous pores; 5 percent nodular plinthite; common distinct clay films on faces of peds; 4 percent ironstone nodules by volume less than 0.75 inches in diameter; common medium prominent yellowish red (5YR 5/6) and common fine prominent red (2.5YR 4/8) masses of iron accumulation; very strongly acid; gradual wavy boundary. Btv2--50 to 60 inches; yellowish brown (10YR 5/8) sandy clay loam; moderate medium subangular blocky structure; firm; 15 percent nodular plinthite; few distinct clay films on faces of peds; 2 percent ironstone nodules; common medium prominent red (2.5YR 4/6) and common medium distinct brownish yellow (10YR 4/6) masses of iron accumulation, and common medium prominent light gray (10YR 7/2) iron depletions; very strongly acid; clear wavy boundary. (Combined thickness of the Btv horizon is 20 to 40 inches ) BC--60 to 65 inches; strong brown (7.5YR 5/6) sandy clay; weak coarse subangular blocky structure; firm; few coarse pores; 2 percent ironstone nodules; common medium prominent red (2.5YR 4/6) masses of iron accumulation and light gray (10YR 7/2) iron depletions; very strongly acid; gradual wavy boundary. C--65 to 80 inches; strong brown (7.5YR 5/8) sandy clay loam; massive; firm; 2 percent plinthite; 2 percent ironstone nodules; many medium prominent red (2.5YR 4/6) masses of iron accumulation, and common medium prominent white (10YR 8/1) iron depletions; very strongly acid. GEOGRAPHIC SETTING: Tifton soils are on nearly level to gently sloping uplands of the Coastal Plain. Slopes range from 0 to 8 percent. Elevation is 100 to 400 feet. The mean annual temperature is 65 to 70 degrees F., and mean annual precipitation is 43 to 50 inches. DRAINAGE AND PERMEABILITY: Well drained; runoff is medium. Permeability is moderate in the Btc horizons and moderately slow in the Btv horizons. Fundamentals of Soil Science [SOIL 2124] Spring 2003 Exam 1A pg. 2 USE AND VEGETATION: Most of the soil is under cultivation with cotton, corn, peanuts, tobacco, vegetable crops, and small grain the principal crops. Some is in pasture. Some areas are in forest, consisting largely of longleaf, loblolly, and slash pines and some hardwoods on cutover areas. DISTRIBUTION AND EXTENT: Tifton soils occur in Georgia, Alabama, Florida, and South Carolina. The series is of large extent. 1) Which soil horizon has the greatest percentage of clay? (remember the textural triangle) a) Apc b) Btc1 c) BC d) Btv2 2) What does the “t” for the Btv1 horizon mean? a) An accumulation of silicate clays b) A tough horizon for roots to penetrate c) A transition horizon between the A and B horizon d) An accumulation of carbonates 3) What is the color chroma for the Tifton soil series in the Btc1 horizon? a) Dark grayish brown b) 2 c) 10 d) 4 4) What does the “2” indicate for the Btv2 horizon? a) A zone of eluviation b) A second parent material c) A second B horizon d) A zone of illuviation 5) (3 pts) What is the parent material for the Tifton soil series? Marine sediments 6) (3 pts) What is the native biota the Tifton series developed under? Coniferous forest with a mix of hardwoods. 7) (4 pts) What does the BC horizon indicate? This is a transition horizon where properties of a B and a C horizon are exhibited. The dominant characteristics are the B horizon. 8) (5 pts) Based on the data provided is there any indication that the Tifton series would not be suitable for installing a septic system within the top 50 inches? What is the evidence? Yes it would be acceptable. There are two pieces of evidence: 1. it is a well drained soil; 2. there are no redoximorphic features in the profile to a depth of 50 inches which is an indicator that water does not accumulate in the profile. 9) (4 pts) What soil forming processes must have occurred relative to the soil texture of the Btv1 horizon? Formation of a Btv horizon is a result of accumulation of silicate clays (addition process). The addition is from the horizon above as a result of water movement through the profile, which is a translocation process. The third Fundamentals of Soil Science [SOIL 2124] Spring 2003 Exam 1A pg. 5 27) The soil separates used to determine soil texture are ? a) ratio of sand, silt, clay and organic matter b) ratio of sand, silt, clay and cation exchange c) ratio of sand, silt and clay d) ratio of sand, silt, clay to aggregation 28) What master horizon is characterized by eluviation of material? a) A b) E c) B d) C 29) Which soil texture is considered to have the “best” combination of properties? a) Clay loam b) Silt c) Loam d) Loamy sand 30) Soil survey manuals will be very important information resources for you in your future career. They are compilation of . a) soil maps b) soil data c) soil uses d) answers A, B and C 31) What soil order is the dominate soil order in the Section B of the map of Oklahoma? a) Alfisols b) Oxisols c) Ultisols d) Mollisols Short Answer 32) (5 pts) What is the definition of a soil? Soil is a dynamic natural body composed of minerals, organic materials, air, and water which acts on and is acted on by living organisms in a thin layer covering the earth's surface. 33) (5 pts) What are the five (5) primary uses for soil? • Plant growth • Hydrologic cycle • Natures recycling • Engineering • Ecosystem 34) (5 pts) What are the five plant growth needs fulfilled from the soil? • Water available to plants • Air supply • Nutrients supply • Temperature regulation A C B Fundamentals of Soil Science [SOIL 2124] Spring 2003 Exam 1A pg. 6 • Support for roots to anchor in 35) (5 pts) What is the difference between the topsoil and A horizon? Topsoil is the upper portion of the profile that is managed for plant growth. Depending on what has previously occurred at the location the topsoil could be composed of the O, A, E, B or C horizon. Management defines topsoil. The A-horizon by definition is the upper mineral horizon that is enriched with soil organic matter. 36) (5 pts) Describe the formation of a soil profile under a coniferous forest. What soil horizons would be expected and why would they form? A diagram would be most appropriate. • Forest profiles are often composed of an O, A, E, B and C horizon. Thiis is a result of the climate suitable to support forest vegettion. The water infiltrating and leaching the soil will supply needed moisture for microbes which will decompose deposited organic and carry dissolved organic matter and acids from the O horizon though the profile. Some of the organic matter will accumulate in the upper mineral horizon forming the A-horizon. As the organic acids are transported throught the A-horizon, they will dissolve minerals present in the soil. This will result in formation of the E horizon which is composed of only the most weather resistant materials. Below the E hoizon the B horizon will form as mateial begins to recrystallize and form clay minerals. Some of the organic matter will also recrystalize. • These soils tend to be acidic due to the significant quantity of leaching that typically occurs and the lack of base cycling due to the root system of the trees. As a result, these soils will be low in plnaat nutrients as a general rule.