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Soil441 Unit 1
Unit 1
| Term | Definition |
|---|---|
| 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 |
| Manure | |
| 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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