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Soil441 Unit 1

Unit 1

Soil The layer(s) of generally loose mineral and/or organic material that are affected by physical, chemical, and/or biological processes at or near the planetary surface and usually holds liquids, gases, and biota and supports plants
Soil Fertility Status of a soil with respect to its ability to supply the nutrients essential to plant growth
Soil Productivity The capacity of a soil in its normal environment, for producing a plant or crop sequence under a specified system of management
Essential nutrient criteria (3) 1. Needed for plant to complete the growth cycle 2. Performs function that can’t be done by another element 3. Directly or indirectly involved in plant metabolic processes
Nutrient deficiency An inadequate supply of essential nutrients
Nutrient toxicity An excess of a nutrient. Causes harm to an organism
Macronutrients Required in large quantities. 0.2-5%
Micronutrients Required in smaller quantities. 0.01-100 ppm
Law of Minimum The most limiting fertility/productivity factor determines plant productivity
Law of Diminishing Returns Plant growth and yield increase with an incremental increase in a limiting nutrient but that gain gets smaller until a yield plateau is reached, and another growth factor is limiting (water, another nutrient, etc.)
Nutrient Management plan goals (4) 1. Resource management 2. Soil quality 3. Environmental Protection 4. Plant yield and/or quality
Nutrient cycling The movement and exchange of organic and inorganic matter back into the production of living matter
Nutrient pools The amount of a particular nutrient stored in a portion the ecosystem
Physical weathering of rocks and minerals Freezing/thawing, temperature variation, salt deposition, wind/water abrasion, root penetration
Primary minerals Formed under high temperature and pressure. Must undergo isomorphic substitution with a lower valence electron. Muscovite mica
Secondary minerals Formed from physical and chemical weathering. Has an overall negative charge that serves as cation exchange sites. High activity clays
Mineral or precipitate dissolution Breakdown of rocks and nutrient release
Precipitation of soluble ions Precipitation of two soluble ions will take those ions out of solution and reduce their immediate reactivity with plant roots. Conversely, dissolution of that precipitate will release soluble ions and increase their immediate availability
Cation Positively charged ion. Ca, K, Na
Anion Negatively charged ion. O, Cl, SO4-
Cation or anion exchange The movement of cations and anions through the soil
Cation or anion Adsorption Adsorption onto exchange sites of the outer space (cell wall, intercellular spaces). Exchange sites are mainly carboxylic groups on pectin, lignin, and other complex polysaccharides of the cell wall.
Ion Absorption Ion entry into the root cell cytoplasm in response to electrochemical gradient between outer solution and cytoplasm across the plasmalemma. May or may not require energy
Humus Stable component of soil organic matter. CEC=200
Organic matter mineralization The decomposition of organic C and nutrients into inorganic forms, or into smaller organic compounds
Organic matter charged functional group Coo-, PO3-, NH3+
Tetrahedral layer Si4+ tetrahedral structure in clays
Octohedral layer Al3+ structure in clays
Edge charge More negatively charged oxygens on the edges which creates cation exchange sites
1:1 clay minerals (definition and examples) Highly weathered (kaolinite)
2:1 clay minerals (definition and examples) Less weathered (vermiculite)
Isomorphous substitution Substitution within the crystalline lattice of divalent or trivalent cations, creating a net negative charge for that structure
Oxide minerals Minerals in which the oxide anion is bonded to one or more metal alloys
Clay, sand, silt Soil textures
Soil aggregation Binding together of several soil particles into secondary units. Important for high water infiltration and good soil structure
Soil acidity Soil pH <7, soil charge becomes more positive
Soil pH Soil pH >7, soil charge becomes more negative
12 major soil orders Entisols, Inceptisols, Andisols, Mollisols, Alfisols, Spodosols, Ultisols, Oxisols, Gelisols, Histosols, Aridisols, and Vertisols
Amino acids Building blocks of protein, and primary components in cells
Proteins 9-16% of organic matter. Made of amino acids
Lipids and phospholipids 1-6% of organic matter
Nucleic acids Bipolymers, essential to all lifeforms. Made out of nucleotides, found in DNA and RNA
Polysaccharides Bond soil particles together (along with humic acids) to promote aggregation
Carbohydrates 5-25% of organic matter
Lignin Strongest component of fiber
Cellulose Crystalline, strong, resistant to hydrolysis. Made of glucose
Hemicellulose Random, amorphous structure with little strength. Easily hydrolyzed. Contains many sugar monomers
Thatch Layer of organic matter that builds up in a turf surface layer. High lignin materials (stems and roots). Occurs when the rate of growth exceeds the rate of decomposition.
Green manure Incorporating plant residue into the soil as a source of fertilizer
Ion leaching Movement of dissolved substances with water percolating through the soil
Nutrient volatilization The loss of gaseous ammonia to the atmosphere
Root interception (contact exchange) Immediate exchange of ions between root and adjacent soil colloids
Mass flow Ions in solution travel with soil water to root surfaces
Diffusion Migration of nutrients to the root surface in response to a concentration gradient
Rhizosphere Zone of soil immediately adjacent to plant roots in which the kinds, numbers, or activities of microorganisms differ from that of the bulk soil
Active transport Nutrient transport against an electrochemical gradient. Requires energy. Sensitive to temperature, and requires oxygen
Passive transport Nutrient transport with an electrochemical gradient
Ion carrier Metabolically activated ion binding compounds that provide passage through ion repelling lipid barrier
Ion pump Force ions through cell membrane to maintain the charge in cell
Ion channel Size determines which nutrient can pass through.
ATPase Example of an ion pump. Catalyzed by the mitochondria
Active ion uptake Active transport against an electrochemical gradient and always requires energy
Passive ion uptake Follows a concentration gradient and may not require energy. Nutrients move from an higher concentration to a lower concentration
Nutrient antagonism Negative interaction between 2 elements, where the presence of one reduced the uptake of the other
Nutrient synergism Presence of one ion enhances the absorption of another
Mole 6.022x10^23. Standard scientific unit for measuring large quantities of very small entities such as atoms
Atomic weight The average mass of an atom of an element
Equivalent weight The mass of a substance especially in grams that combines with or is chemically equivalent to 8 grams of oxygen or one gram of hydrogen. Atomic weight divided by the valence
Cation, anion exchange capacities The ability of soil to hold nutrients. Higher CEC means more fertile soil
ppm of solids or solutions Parts per million
acre, hectare 1 acre=0.405 ha, 1 ha=2.47 A
liter, gallon 1 gal=3.79 L, 1 L=0.2642 gal
kg, lb 1 lb=0.453 kg, 1 kg=2.2 lb
Limestone Carbonate sedimentary rock, parent of mollisol soil group. Can be applied to soil to increase pH
Saltpeter Early source of nutrients. KNO3, found in manure
Ashes Soil amendment used to add nutrients and raise the soil pH
Guano Bat manure that is high in nutrients and mined for fertilizer
Pulse crop Nitrogen fixing legumes
van Helmont One of first quantitative experiments in plant nutrition. Weighed 200 lbs of soil, only gave a willow shoot water for 5 years, determined that plants get their mass from water
Glauber Identified saltpeter (KNO3) in manure. Recognized that it may be part of a cycle between plants-animals-soil
Boyle Determined relationship between gas and volume (PV=nRT). Determined salts, spirits, earth, and oil as plant components
von Liebig Law of the Minimum: crop yields are in proportion to the most limiting growth factor
Mitscherlich Law of Diminishing Returns: incremental increases in yield in response to a nutrient diminishes as the availability of that nutrient increases
Hellriegal and Wilfarth N fixation by bacteria in the nodules of legumes
Mapes 1851: Built first P fertilizer plant on Long Island, NY
Haber-Bosch N fixing process. Originally for nuclear weapons in Germany
Created by: mbsassy



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