Term
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Definition
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Term
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Definition
| attraction of molecules for each other |
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Definition
| attraction of molecules for solid surfaces |
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Definition
| a property of liquids arising from unbalanced molecular cohesive forces at or near the surface, as a result of which the surface tends to contract and has properties resembling those of a stretched elastic membrane |
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Definition
rise of water in a capillary tube
caused by adhesion and cohesion
height of tube in water is inversely proportional to the diameter of the tube |
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Term
| gravimetric water content |
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Definition
| mass of water per unit mass of oven dry soil |
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Definition
| volume of water per unit volume of soil |
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Definition
| amount of water in a given depth of soil |
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Term
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Definition
energy status of soil water - a measure of the difference between the free energy state of soil water and that of pure water
always moves to areas of lower potential |
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Term
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Definition
| refers to the ability to do work |
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Term
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Definition
| the amount of work that must be done per unit of a specified quantity of pure water in order to transport reversibly and isothermally an infinitesimal quantity of water from a specified source to a specified destination |
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Definition
portion of the toal soil water potential due to the attractive forces between water and soil solids, adsorption and capillarity
always negative |
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Definition
| portion of the total soil water potential due to differences in elevation |
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Definition
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Definition
| portion of the total soil water potential due to the presence of dissolved solutes |
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Definition
| fast-moving neutrons interact with hydrogen atoms in water; this scatters and slows the particles |
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Term
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Definition
| relationship between soil water potential and soil water conetent |
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Term
| Time Domain Reflectometry |
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Definition
| electrical pulse applied to waveguides, travels their length, then is reflected back when it reaches the end of the waveguides |
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Term
| Visible Near Infrared Diffuse Reflectance Spectometry |
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Definition
| visible and near-infrared light directed at the soil. Detector analyzes wavelengths which are reflected back |
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Term
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Definition
| electrical resistance of porous material equilibrated with soil moisture can be calibrated against soil moisture |
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Term
| Dielectric moisture sensors |
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Definition
| two electrodes are inserted into soil, which becomes the dielectric medium separating them |
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Term
| gravimetric water content |
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Definition
| ratio of weight loss in drying to dry weight of sample |
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Term
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Definition
| fraction of soil volume occupied by water |
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Term
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Definition
| soils are not uniform in their hydraulic properties, causing discontinuous water movement |
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Definition
| the portion of stored woil water that can be absorbed by plants at a rate sufficient to sustain the life of the plaint |
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Definition
| the portion of the soil water that will freely drain from the soil due to the force of gravity |
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Definition
| the greatest amount of water that a soil can hold after gravitational water has drained |
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Definition
| water at the permanent wilting point is held so tightly that plants cannot remove the water from the soil |
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Definition
| all soil pores are filled with water |
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Definition
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Definition
| moves in response to differences in vapor pressure |
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Term
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Definition
| the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans |
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Term
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Definition
| some carbon is converted into soil organic matter and stored |
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Term
| global warming potentials |
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Definition
| developed to allow comparisons of the global warming impacts of different gases. CO2 by definition has a value of 1 regardless of the time period used because it is the reference gas |
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Term
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Definition
| gas which has a relatively high GWP |
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Definition
| the organic fraction of the soil that includes plant and animal residues at vrious stages of decomposition, cells and tissue of organisms, and substances synthesized by the soil population |
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Term
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Definition
| total of the organic compounds in soil exclusive of undecayed plant and animal tissues, their "partial decomposition" products, and the soil biomass |
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Term
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Definition
| potassium dichromate digestion technique with titration using ferrous ammonium sulfate |
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Term
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Definition
| gravimetric test using oven dry versus ash sample weights |
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Term
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Definition
provides total C and N analysis of soil, compost, and forage. High temperature combustion with elemental detection
Detects C from 0.002 - 100%
Detects N from 0.004% - 100% |
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Term
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Definition
| simple one-celled organisms. Most abundant microorganism in the soil. Often link together to form colonies on the surface of soil particles. Prefer neutral to alkaline soils |
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Term
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Definition
| exist as threads of hyphae. attack matter that resists microbial breakdown. Prefer acidic soils. |
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Term
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Definition
| especially tolerant of dry soil but resemble fungi. Thrive under alkaline and hot conditions. Produce chemicals that stop the growth of other microorganisms |
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Term
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Definition
| simple chlorophyll-containing plants living in aqueous environments. Prefer acid to neutral soils and dominantly found at or near the surface |
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Term
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Definition
| microscopic eel-like worms with a needle-like mouth. |
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Definition
| ratio of the mass of carbon to the mass of organic nitrogen in soil |
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Term
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Definition
| a process of creating humus-like materials outside of the soil through a combination of piling, mixing, and storing organic material |
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Term
| ambient temperature composting |
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Definition
| similar to natural organic matter decay but occurring outside of the soil |
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Term
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Definition
| utilizes special earthworms to help transform raw materials into finished compost |
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Term
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Definition
| piled compost that generates a considerable quantity of heat, 160°F |
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Term
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Definition
| the wearing away (detachment and movement) of the land surface by running water, wind, ice, or other geologic agents |
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Term
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Definition
| natural erosion caused by the geologic processes acting overl ong periods of time |
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Term
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Definition
| erosion that is much more rapid and influenced by the activity of humans or animals |
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Term
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Definition
erosion whereby water accumulates in narrow channels and over short periods removes the soil from the channel
30 cm - 30m |
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Term
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Definition
| numerous small channels several cm deep which are erased by tillage. often tied to soils with very fine sand or silty textures |
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Term
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Definition
| bouncing or jumping action of particles falling from wind or water or impacted by other falling particles in wind or water flow |
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Term
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Definition
rolling or slow movement of particles too large to be carried in the wind or flowing water
gravity driven |
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Term
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Definition
| caused by direct strikes by raindrops, resulting in moving particles up to 3 feet away |
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Term
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Definition
| the more or less uniform removal of a layer of soil from other land surface |
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Term
| Universal soil loss equation |
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Definition
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Term
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Definition
| computerized version of the USLE with improvements in many of the factor estimates. released for public use in 1992. includes site-specific data, seasonal changes in weather patterns, complex slope modelling, and hydrologic soil groups |
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Term
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Definition
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Definition
| influenced by infiltration rate, water holding capacity, aggregates, and structure. K |
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Term
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Definition
| distance from the point of origin of overland flow to a point where slope decreases enough that there is deposition, or the point where runoff enters a well-defined channel L |
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Term
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Definition
| increases with velocity of runoff S |
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Term
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Definition
| crop type, tillage, and residue management C |
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Term
| erosion control and conservation practices |
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Definition
| contour tillage > Strip cropping > terraces P |
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Term
| Soil Loss tolerance factor |
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Definition
| maximum rate of annual soil loss that will permit crop productivity to be obtained economically and indefinitely |
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Term
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Definition
| violent and oppressive wind blowing in summer bringing sand from surrounding areas |
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Term
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Definition
0.1 - 0.5 mm particles move over surface due to wind, jumping vertically about 30cm. Can dislodge other particles
50 - 75% |
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Term
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Definition
| extremely fine particles >0.005mm carried relatively long distanes in the air 3 - 40% |
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Term
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Definition
| movement of particles too large to be picked up by the wind, and are instead rolled or pushed along 5 - 25% |
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Term
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Definition
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Term
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Definition
wind frequency, speed, and moisture
C |
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Term
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Definition
| function of structure and texture I |
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Term
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Definition
| reduces wind velocity at soil surface and traps soil particles, reducing erodibility K |
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Term
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Definition
erosion increases with the distance of sol that is exposed to the wind
L |
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Term
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Definition
| reduces wind velocity at soil surface and traps soil particles. Roots can bind particles together. V |
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Term
| Conservation reserve program |
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Definition
provides technical and financial assistance to eligible farmers and ranchers to address soil, water, and related natural resource concerns on their lands in an environmentally beneficial and cost-effective manner. Administered by the Farm Service Agency
Provided for by the Farm bill of 1985 |
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Term
| Environmental Quality Incentives program |
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Definition
| voluntary program that provides financial and technical assistance to agricultural producers to plan and implement conservation practices that improve soil, water, plant, animal, air, and related natural resources on agricultural land and non-industrial private forestland |
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Term
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Definition
| composed of all the reactions and processes responsible for N inputs, transformations, and losses from terrestrial ecosystems |
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Term
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Definition
| converting dinitrogen gas into forms available for plants |
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Term
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Definition
N2 + 8H+ > 2NH3 + H2 > amino acids > proteins
driven by nitrogenase enzyme |
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Term
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Definition
N2 + 3H2 > 2NH3
1200°C and 500 atm
arguably one of them ost important scientific advances of the INdusttiral Revolution
Industrial form of nonbiological dinitrogen fixation |
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Term
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Definition
conversion of inorganic N to organic N
favored by the addition of wide C:N materials |
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Term
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Definition
conversion of organic N into inorganic N
good thing from a plant standpoint
increases the amount of plant available N |
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Term
| Mineralization immobilization turnover |
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Definition
| equilibrium resulting as mineralization and immobilization occur simultaneously |
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Term
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Definition
two-step biological oxidation of ammonium to nitrate
not desirable as nitrates are prone to leaching |
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Term
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Definition
biological reduction of oxidized N to reduced forms of N
nitrate is converted to nitrous oxide or dinitrogen gas
represents a loss mechanism from an agricultural point of view |
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Term
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Definition
NH4+ + OH- <> H2O + NH3
right: favored by high pH, dry soil |
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Term
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Definition
accounts for 14% of total N fertilization
rapidly produces ammonium, catalyzed by urease |
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Term
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Definition
| decomposition of a chemical compound by reaction with water |
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Term
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Definition
| movement of nitrates through the soil with water. very susceptible to leaching and very undesirable |
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Term
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Definition
| blue baby syndrome caused by water polluted with nitrates |
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