SWS3022 Exam 1 Study Guide with Complete Solutions

SWS3022 Exam 1 Study Guide with Complete Solutions Dimensions of the Earth - Answer️️ -Diameter: 8000 mi Circumference: 25,000 mi What do the definitions of soil depend on? - Answer️️ -The definition of soil is dynamic because many specializations and disciplines view soil differently: ecological, geological, environmental, etc. Parameters related to soil composition for an idealized surface soil - Answer️️ -50% pore space and 45% particles, 5% OM Basic functions of soils in the environment - Answer️️ -Medium for plant growth: support, gas and water exchange, temperature control, nutrient storage and release. Regulator for water supplies: infiltration, runoff, storage, movement, purification. The 4 basic processes involved in soil formation - Answer️️ -Additions, losses, transformations, translocations Basics of weathering - Answer️️ -Critical to Soil Formation, Physical and Chemical Alteration and Reorganization of Rocks and Minerals. Critical in the Creation of the Parent Material and Alteration of Parent Material to Secondary Components. ©SOPHIABENNETT EXAM SOLUTIONS_2024/2025 Tuesday, September 3, 2024 10:30 AM Page | 2 5 soil forming factors - Answer️️ -Parent material, climate, organisms, relief (topography), and time Type of parent material that dominates Florida's soils - Answer️️ -Loamy marine sediments; Sandy and clayey marine and alluvial (deposited by rivers and streams) deposited over limestone bedrock; Mostly calcium and magnesium carbonates from original ocean species like corals and mollusks What is the origin of the sediments that ultimately formed the parent materials for Florida soils? - Answer️️ -An influx of continental sediments began about 25 mya; the sediments were shed from the Appalachian mountains by the lowering sea levels How do rainfall and temperature impact soil formation? - Answer️️ -Increased temperature and rainfall both accelerate soil formation. High temperatures increase the rate of physiological processes (microbial activity, organisms) while water increases the rate of weathering and translocation, ultimately increasing the rate of transformation. Why are soils in Florida more developed compared to soils in the west? - Answer️️ -In the east there is more rainfall, causing faster weathering and soil transformation. This causes more differentiated soil horizons. What is pedogenesis? - Answer️️ -The process of soil formation as a result of the combination of soil forming processes mediated by soil forming factors What are soil horizons? - Answer️️ -Roughly parallel layers of soil with varying compositions and properties 6 major master horizons - Answer️️ -O, A, E, B, C, R ©SOPHIABENNETT EXAM SOLUTIONS_2024/2025 Tuesday, September 3, 2024 10:30 AM Page | 3 O Horizon - Answer️️ -Surface organic horizon (>20% OM) Derived from the decomposition of plant and animal residues Differentiated based on degree of decomposition A Horizon - Answer️️ -Topmost mineral surface horizon (topsoil) Subject to significant weathering, accumulates OM, often darker than the soil below, high in plant roots and biotic activity, zone of gas and water exchange E Horizon - Answer️️ -Zone of elluviation, maximum losses by translocations (of OM, clays, carbonates, Fe and Al oxides). Generally lighter in color and contains resistant primary materials (like quartz). B Horizon - Answer️️ -Usually a zone of illuviation. Accumulates material (OM, clays, Fe/Al, salts) lost from above or forms in place. Potential color development and high reactivity due to secondary minerals and OM. Subordinate letter indicates what is accumulating. C Horizon - Answer️️ -Closely resembles parent material, unconsolidated, little or no evidence of alteration or development. R Horizon - Answer️️ -Bedrock Subordinate (minor) horizons - Answer️️ -Applies to certain horizons; further distinction of layers a,e,i horizons - Answer️️ -Applies to O horizon. Differentiated b