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GENERAL AGRICULTURAL in/ft of in very fine sandy loam and silt TERMINOLOGY loam.

Articles posted on this website contain terms Banded. placed below and to the and phrases that are specific to or side of at planting, or applied agricultural enterprises and activities. The to a defined width that includes the planted below definitions (listed alphabetically) should row. aid in the understanding of the content of these articles and articles that are linked in them. Biennial rotation. Practice of growing two different in alternating years. Examples– Abiotic. Environmental factors such as corn and soybeans, rice and soybeans. , , hail, or excess moisture that impact the growth of living organisms. Usually Biological control. management that used as “abiotic stresses”. protects, augments, or releases organisms that are natural enemies of a pest. Biological Adsorb, adsorption. In soil terms, the control agents are important in Integrated Pest adhesion of ions (i.e., K+, Ca++) or molecules to Management systems. the surface of soil particles. This process differs from absorption where a material–the Biomass– definition. matter absorbate–is dissolved in the soil solution. expressed on a dry weight basis (after removal of all water) that can be converted to an energy Alluvial Soil. Soil that is deposited by water or fuel source by either direct or indirect flowing over plains, river valleys, and methods. In today’s agriculture, the most creek bottoms; may be coarse- to fine-textured, popular indirect method is conversion to depending on proximity to water deposition ethanol. source. Usually the product of from an uphill or upstream source; thus the term Biotic. Biological factors such as , “Lower Mississippi River Valley alluvium”. disease pathogens, , and weeds that affect other living organisms. Aquifer. Porous, underground deposit of permeable rock or sediment such as or Breakeven price. Per-unit revenue (or gravel that contains water that can be used to income) required to provide an economically supply . Pores in the deposits are sustainable enterprise; calculated by dividing a interconnected so that water flows through cost (e.g., dollars/acre) by a production them over a large area. Aquifers may be quantity (e.g., bushels/acre). shallow (the Delta aquifer) or deep. Broadcast. Fertilizer spread on the soil Available holding capacity. The surface, or herbicides applied across the entire amount of soil water that is available for plant width of a cropped or planted area. use, or the amount of water volume between C factor. Cover management factor used in the field capacity and permanent wilting point. Revised Universal Soil Loss Equation that Available water ranges from an average 0.7 in/ft of soil in coarse sand to an average 2.25 WWW.MSSOY.ORG. June 2015 1

reflects the effect of cropping and management result in a that is essentially free of practices on erosion rates. weeds and plant residue cover. This is the antithesis of conservation . Cation exchange capacity (CEC). Refers to the quantity of negative charges that exist on Cover . Crop grown to provide soil cover the surfaces of clay particles and organic during seasons when an annual grain crop is matter in soil. These negative charges attract absent. positively charged ions or cations such as potassium (K+), calcium (Ca++), magnesium . Practice of growing two or more annual crops in a given field in a planned (Mg++), and ammonium (NH4+), which are major plant nutrients. Hydrogen (H+), sodium pattern or sequence in successive crop years. + +++ (Na ), and aluminum (Al ) are the other Cultural control. Pest management that uses predominant cations occupying the CEC in . tillage, sanitation, harvesting, and other High percentages of clay particles will impart a techniques to alter the pest’s environment. higher CEC, while a high percentage of sand Includes practices that enhance plant particles will impart a low CEC. Small to overcome the effects of pest increases in organic matter will greatly injury. increase soil CEC. The CEC of a soil is important because it implies the size of the Deep tillage. Mechanical operations with reservoir of nutrients that is available to implements that affect soil properties below 6 replenish the nutrients removed by plant inches. This can be compatible with uptake. Also, the CEC of a soil can be an conservation tillage if the soil surface is indicator of how much of nitrogen and relatively undisturbed by the operation. potassium will occur; i.e., higher CEC soils will experience less leaching of cationic Disease. Plant injury from elements. resulting from infection by fungi, oomycetes, nematodes, bacteria, or viruses. Cellulosic ethanol. Biofuel that is produced from lignocellulose, the structural material that Doublecrop. Growing two crops alternately comprises the mass of most . Corn during a 12-month period. stover, switchgrass, and wheat straw are Dryland production system. Growing a crop common agricultural sources of lignocellulose without supplemental water or . that are being/can be used in cellulosic ethanol production. Enterprise budget. Type of financial report that owners or managers may use to Conservation tillage. Limited mechanical help make decisions. After defining the specific operations with implements that result in the production techniques to be used by the soil surface being covered with >30% plant enterprise (e.g., a crop produced with no-till residue. practices), the budget typically will have a Conventional tillage system. Combination of section describing the projected dollar values mechanical operations with implements that (usually on a per-acre or per-bushel basis) for WWW.MSSOY.ORG. June 2015 2

gross receipts, operating costs, ownership Host-plant resistance. Genetically controlled costs, and returns above costs. These are innate or bred phenotypic or physiological generated by computer programs such as the property of a plant that enables it to withstand Mississippi State Budget Generator. injury from feeding and pathogenic infection. Erosion. Undesirable displacement of soil from a site by wind and/or water. Identity preserved (IP). Refers to identification and maintenance through Fallow. Land normally used for the marketing channels (usually through contract- production of a crop (cultivated land) that is growing for a higher or premium price) of seed left idle with no crops growing on it for a with specific traits or characteristics that are season. Fallow land may be untilled or tilled sought or preferred by users. during the idle period. The fallow practice is often used to destroy weeds and conserve soil Integrated pest management (IPM). The moisture. ecologically based decision support system for managing weeds, plant pathogens, and insect Farm gate value. Value of an agricultural crop pests while minimizing use of agrichemicals. when it leaves the farm, usually synonymous Combines complementary and compatible with the selling price of the product. biological, chemical, and cultural control tactics Field capacity (FC). The volume of water in to make pest management economical, remaining in soil after gravitational water flow environmentally sound, and socially acceptable. has ceased. This point of soil is Leaching (Leachate). As related to soil, the generally accepted as about 0.3 bar tension. downward movement of dissolved material . Genetic makeup of an organism (as through soil by percolation, which is the distinguished from its phenotype or physical gravitational movement of water through the characteristics), or the total of genes that are soil pores. Often results in the complete transmitted from parent to offspring. removal of the dissolved material. (The material being leached). Germplasm. Collection of diverse genetic resources (e.g, soybean seed) that are available Macronutrient. An essential nutrient element to be used in the development of improved that is needed by plants in relatively large breeding lines and varieties. quantities. Elements are N (Nitrogen), P (Phosphorus), K (Potassium), S (Sulfur), Ca . Chemical substance or cultured (Calcium), and Mg (Magnesium). biological organism used to kill or suppress the growth of plants. Micronutrient. An essential nutrient element that is needed by plants in small quantities. Herbicide-Tolerant. Ability of a plant to Elements are Cl (Chlorine), Fe (Iron), B (Boron), survive and reproduce after herbicide Mn (Manganese), Zn (Zinc), Cu (Copper), Mo treatment. Often used interchangeably with (Molybdenum), and Ni (Nickel). Herbicide-Resistant.

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Net returns. The estimated dollar value of the Nodules. Small bodies or organelles (on the projected gross receipts minus the projected soybean root surface) that contain Rhizobium costs that have been allocated to a particular bacteria. farm enterprise. Net returns (or returns above costs) represent a residual return to all factors Non-selective herbicide. Chemical compound of production for which a cost has not already that is generally toxic to all plants treated; used been included. For example, an enterprise to kill a wide range of plant species that usually budget may include a cost for all inputs except includes crop species in the treated area. Some land. In this case, the net return (if positive) selective herbicides may become nonselective would represent the amount available to pay if used at very high rates. for a land charge. Another example might be a Oxidation of organic matter. Breakdown of case in which all inputs except management organic matter by microbial activity. Process is have been included in the cost estimate. In temperature driven; therefore, more such a case, the net return would be the pronounced in the Midsouth which has amount available to pay for the management relatively mild winters. functions related to the enterprise. Net returns may be negative, indicating that the revenue Percolation. As related to soil, the generated by the enterprise is not capable of gravitational (downward) movement of water covering all allocated costs. The statement with dissolved minerals through the soil pores. “Net return to land, management, and general farm overhead” indicates that all costs except Perennial. Plant species that have a life cycle those associated with the three listed items lasting more than two years. Perennnial plants have been accounted for in the calculated net survive winter and environmental stresses as return. underground tissues such as roots, rhizomes, bulbs, or tubers. Nitrogen fixation. Process by which atmospheric nitrogen is combined with other Permanent wilting point (PWP). The volume elements to form inorganic compounds which of water remaining in soil when plants can no can then be converted by nitrification into longer extract water, and the point at which a nutrients that can readily be absorbed by plant will not recover from wilt until water is plants and used for making more complex added to soil. This point of soil water content organic compounds. Specifically, conversion of is generally accepted as about 15 bars tension. atmospheric nitrogen into nitrogen compounds Phenotype. Physical appearance of an by Rhizobium bacteria in the root nodules of organism (as distinguished from its genotype) legumes. that results from the interaction of its genotype Nitrification inhibitors. Chemical compounds with the environment, which includes such added to nitrogen fertilizer for the purpose of factors as light, , and temperature. reducing the rate of conversion of ammonium Plant introduction (PI). Germplasm brought form of fertilizer to nitrate form. to the United States from other parts of the

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world to provide new genes for potential Soil persistence. Refers to the length of time improvement of crop productivity. that a herbicide applied to or in soil remains effective. Plant pathogen. Fungi, oomycetes, nematodes, bacteria, or viruses that infect plants and cause Soil porosity. Refers to the amount of pore or injury and/or disease. open space between soil particles. Pores are created by the contact between soil particles. Plant residue cover. Plant material remaining Fine-textured soils have more total pore space on the soil surface after crop harvest. Often than coarse-textured soils; however, the pores used in relation to definition of tillage systems. are much smaller than those in soils with a Reduced tillage system. Limited mechanical high sand content. Thus, clay soils (more fine operations with implements that result in the particles) hold more water than coarse- soil surface being covered with 15 to 30% textured sandy soils, but because of the large plant residue. surface area associated with the smaller clay particles, much of this water is adsorbed and Residual herbicide. A herbicide that persists difficult for plants to extract. in the soil and injures or kills germinating . Classification of a soil based on weed seedlings for a relatively short period of time after application. its percentage of sand (largest particles), silt, and clay (smallest particles). Soil properties Rhizobium. Group of nitrogen-fixing bacteria such as speed of internal drainage, water that are found in the nodules affixed to roots of holding capacity, available water holding legume species. capacity, aeration, susceptibility to erosion, and cation exchange capacity (CEC) are Ridge tillage. Soil is mounded up (a ridge or influenced by texture. Soils that have a bed is built) in the fall of the year and the crop predominance of clay particles are called fine- is then planted on top of this shallow ridge or textured soils, while those dominated by larger bed. particles are called coarse-textured soils.

Row spacing. Lateral spacing between plants Soil Water holding capacity. The amount of that are planted in a row or drill. water that is held in a soil after gravitational water loss has ceased. Selective herbicide/. A chemical compound that kills only certain species of Stale seedbed planting system. A seedbed plants or plant pathogens. Broad or narrow that has received no seedbed preparation spectrum, depending on the compound. tillage just prior to planting. It may or may not have been tilled since harvest of the preceding Soil bulk density. The ratio of dry soil mass to crop. Any tillage conducted in the fall, winter, a known soil volume, including pore spaces. or early spring will have occurred sufficiently Usually given in g/cm3 using undisturbed, ahead of planting time to allow the seedbed to oven-dried soil obtained from a core sample settle or become stale. A crop is planted in this with a known volume. unprepared seedbed, and weeds present WWW.MSSOY.ORG. June 2015 5

before or at planting are killed with herbicides. Value-added trait. A quality trait or This system does not preclude tillage because characteristic that increases the value of a crop it is a minimum or reduced tillage concept product relative to its typical or commodity rather than a no-till concept. version, and that requires a uniform and uncontaminated end product; in soybean, Symbiotic nitrogen fixation. The conversion commonly referred to as specialty varieties of N2 from the atmosphere to inorganic with specific physical or chemical nitrogen by that live in characteristics that are required for specific nodules on the roots of soybean plants. markets. “Symbiotic” indicates that both the Rhizobium bacteria in the nodules and the host plant (e.g., Variable rate application. Applying nutrients soybean) receive mutual benefit from the at differing rates on specific areas of an relationship. individual field based on the specific and differing requirements of those areas. Tillage system. A combination of mechanical operations with implements that alter the soil Varietal resistance. Resistance of a particular environment to effect crop production. variety to injury caused by herbicides, pathogens, or insects. Resistance to the same Tolerant. The inherent ability of a plant to pest may be expressed at different levels survive and reproduce after application of among different varieties of the same species. herbicides or during infestation by plant Often synonymous with Host-Plant pathogens. May either be inherent (natural) or Resistance. acquired through genetic manipulation. Often used synonymously with Resistant, which . The process of reducing weed implies that a plant is either immune to or growth and/or infestation to an acceptable unaffected by particular biotic or abiotic level. Often synonymous with weed stresses. management.

Upland soil. Soil on elevated land that: (1) is Composed by Larry G. Heatherly, Updated June 2015, located outside of a flood plain, (2) is not [email protected] subject to flooding, (3) may be subject to erosion, and (4) may have been subjected to long-term erosion and subsequent loss of a portion of .

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