Download SOIL 205 – SPR 2013 Final Exam Study Topics SOIL

SOIL 205 – SPR 2013 Final Exam Study Topics SOIL COMPOSITION & FORMATION 1. Soil as a 3-­‐phase system – what are they? 2. Components of a soil volume – what are the relative proportions of pore space and mineral and organic solids? – what are the dominant chemical elements? 3. The 5 Soil-­‐forming Factors and the 4 general soil-­‐forming processes – what are they and how do they influence soils? 4. The 12 Soil Orders – what are the distinguishing characteristics of each? SOIL PHYSICAL PROPERTIES 1. Texture – be familiar with the textural triangle; know how it works and where the various classes are found – how is texture related to soil properties, e.g. water storage capacity, susceptibility to erosion, nutrient storage capacity, etc.? 2. Structure – definition and role in soils – what are the various types of structure and where are they found? 3. Bulk density – define and know how to calculate – relationships between bulk density and texture, structure, etc. – how is it affected by management? 4. Porosity – how is it related to bulk density and how is it calculated? – macropores vs. micropores 5. Engineering properties – types of soils (non-­‐cohesive, expansive, etc.) 6. Soil color – significance 7. Soil temperature – effect on soil processes – how managed/controlled? effects of mulches SOIL EROSION 1. Overview – global scale & US; wind vs. water erosion? – modeling water erosion – Universal Soil Loss Equation; WEPP model 2. Conservation practices – conservation at the national level – approaches and programs SOIL WATER 1. Properties of water – adhesion, cohesion, capillarity 2. How soil water status is expressed: Θm, Θv, soil water potential (ψ) – know how to calculate Θm and Θv !! – saturation, field capacity, wilting point, air dry, oven dry – how are these defined and what is their practical significance? – relationship between ψ, soil water content, texture – make sure you understand Fig. 5.7 in text! – how is plant-­‐available water defined and what are the factors that influence it? 3. Water movement in soil – infiltration vs. percolation – hydraulic conductivity – factors that affect it; Fig. 5.15 in text – water movement in layered soils (video clips shown in class) 4. Soil-­‐water balance (P = ET + SS + S) – what are the components and how they may be altered through management 5. Water management – principles (e.g. irrigation, mulches, drainage etc.) SOIL CHEMICAL PROPERTIES 1. Elements, minerals, and rocks – abundance of elements in the Earth’s crust – definitions and examples of elements, minerals, rocks 2. Cation Exchange Capacity (CEC) – what is it and where does it come from?; permanent vs. pH-­‐dependent charge – how is it measured? how to calculate from exchangeable cation data – relative contributions of various soil components – what is a cmol of charge? 3. Cation exchange – exchangeable cations; common ones in soils – cmol weight calculation – % base saturation – significance and how to calculate 4. Soil pH – pH definition, range in soils – effects on nutrient availability and toxicity 5. Soils and acid deposition – what causes it and its effect on soil systems? – soil buffering capacity – what is it and what soil factors contribute to it? 6. Saline and sodic soils – definition of a saline soil and effects on plant growth – definition of a sodic soil and effects of high exchangeable Na+ in soils; calculation of exchangeable Na % SOIL ORGANIC MATTER & BIOLOGY 1. Soil organisms – the soil food web – producers vs. consumers – examples and functions of bacteria, fungi, and actinomycetes– conditions affecting microbial activity 2. Soil organic matter – definition, composition – general process of decomposition; factors affecting this – C:N ratios -­‐ what are these and why are they important? – factors that determine organic matter levels in soils 3. Composting – what is compost? – principles of the composting process – immobilization, mineralization 4. Soils and the global C cycle – role of soils SOIL FERTILITY 1. 17 plant-­‐essential nutrients – macro-­‐ vs. micronutrients 2. nitrogen cycle – major processes affecting available N pool (N2 fixation, mineralization, denitrification, etc.) 3. general principles of nutrient management 4. trends in world food production