Term
| Basics of no-till agriculture: Pros/cons |
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Definition
-Herbicides developed so that you can plant seeds in soil covered by chemically killed grass sod or dead plant residue of previous crop, no bare soil exposure.
-PROS: reduce wind/water erosion, increase land use, slopes less eroded so can now be cropped, less energy, TIMING of planting/harvest improved, can better manage well-drained soils that are hard to till when wet, soil water retained/used more effectively by plants due to decreased water evap. from soil(mulch reduces evap)& increased water infiltration into soil, less machinery investment
CONS: Higher # of insects/disease-producing organisms/rodent habitats(Cn be controlled by rodentcides), greater management ability required since there are fewer alternatives for correcting management errors, soil temp. buffered by mulch takes longer to heat up after winter frost, delaying spring planting, increased pesticide(50%)/herbicide use, but less erosion so less movement from field to external sources so it may be less pollutant than conventional due to reduced runoff. |
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Term
| Problems with cows on soil erosion on land(not near streams) |
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Definition
-small hooves/heavy pressure on small area
-increased pressure on slopes
-create trails: can form rills/gullys
-heavy compaction(lose infiltration), especially when wet
-meso-micro relief: differential compaction that increases surface roughness.
-reduce grass cover by grazing/compaction
-FORESTS NOT AS IMPACTED: Resilient due to high organic matter on surface(buffering), better aggregates, high macroporosity due to high fauna population, less foliage to eat so less cows grazing. |
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Term
| problems with cows near water |
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Definition
-love water! come and go many times daily, especially in summer
-break down banks,
-reduce resistance by eating vegetation
-graze often near water because of higher foliage, shade. |
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Term
| IMPORTANT: List and discribe environmental planning and analysis factors for soil! |
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Definition
-Engineering uses
-whats the depth to bedrock: natural or human induced(plowing compaction) impermeable layer.
-Seasonal water table: urban problem for foundation & septic tanks.
-limits for septic tanks
-texture
-atterberg limits(can damage foundation): for fine-grained sand, how it acts under different water levels; becomes liquid viscosity(@ what level?) & elasticity- what portion of water would soil become plastic instead of brittle.
-permeability
-available water capacity: field capacity minus wilting pt
-pH:extremes are bad
-salinity
-shrink/swell factor
-suitability for topsoil, roadfill, recreation, dams
-hydrologic soil group: A-D, after soil gets wet, how long it takes to infiltrate.
-drainage
-Irrigation: functon of infiltration & erodibility and others
-Bulk/dry density: weight per volume, usually 90lbs |
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Term
| whats the difference between permeability and infiltration? |
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Definition
-permeability: ease of movement through soil
-infiltration: ability to enter soil |
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Term
| Are we in danger of running out of ag space? |
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Definition
| No, we have used a lot of our best agricultural land for urban expansion BUT we've only consumed 2% of land in US much of it in class 1,2,3 |
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Term
| What are the types of crops? how they're grown? (row/grain/forage) |
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Definition
-Row crops: corn, cotton soy, sorghum; need rows to get cultivating tools through, rows for water, separated nutrient consumption, EXPOSE more soil to erosion
-small grain(cereal) wheat/barley/rye/oats; grown in rotation w/ crops, can be grown w/ row crops, in rows
-forage: alfalfa, clover; animal feed, give density/reduce erosion, can be BAD: hay, almost entire biomass above ground removed, multiple crops/yr |
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Term
| Why are crops grown on bare soil? |
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Definition
-other plants steal nuits, can use no-till & herbicide to kill off, but leave biomass.
-herbicides not bad, outweigh costs
-fodder crops grown(animal food), removed instead of incorporated in green manure because more profitable to sell, removing biomass removes nuits
-Bare soil for orchards: create leaf litter, grasses sometime grow beneat but compete for water, trimmings can be put as mulch(avoid oranges they acidify- make soil hydrophobic(repel water)) |
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Term
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Definition
-makes plants grow bigger/faster
-higher productivity/lower erosion
-pH always heading towards acidic, must be maintained because it determines if plants can obtain nuitrients from soil**** |
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Term
| Measures that must be taken for cattle grazing! |
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Definition
-Can't turn them on field freely
-can damage water quality & compact/decrease resistance of soil
-Solution: high level management, graze in small quadrants, rotation grazing, fence off streams, pump water out of streams into tanks for animals, reseed areas |
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Term
| Why rotate crops? Why monoculture? |
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Definition
-Monoculture: when you find your niche you stick to it and maximize potential
-Rotation: move from non-concerving plants to restorative; i.e. cotton/red clover example(but compete for water), -use nurse crops(plants that help other plants grow in conjunction)
-use cover crops: grown in offseason to protect soil, or along w/ crop so it emerges later on, can be plowed in as green manure or harvested. |
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Term
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Definition
-Growing crops in a systematic
arrangement of
strips across a field. Types
of strip cropping include
contour, field or buffer.
-purpose:Reduce soil erosion from
water
• Reduce the transport of
sediment and other waterborne
contaminants
• Reduce soil erosion from
wind
• Protect growing crops
from damage by windborne
soil particles
• Improve water quality
-How does it work:Strip cropping is effective
due to the precise
arrangement of the alternating
strips in the field. The
crops are arranged so that a
strip of grass or close-grow-ing crop is alternated with
a clean-tilled strip or a strip
with less protective cover.
Generally, the strip widths
are equal across the field. |
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Term
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Definition
| Tilling is used to remove weeds, mix in soil amendments like fertilizers, shape the soil into rows for crop plants and furrows for irrigation, and prepare the surface for seeding. This can lead to unfavorable effects, like soil compaction; loss of organic matter; degradation of soil aggregates; death or disruption of soil microbes and other organisms including mycorrhiza, arthropods, and earthworms;[1] and soil erosion where topsoil is blown or washed away. |
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Term
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Definition
-mowboard: cut through soil & flops it over, makes soil rough
-lister: sharp edged, throws soil to either side, creates ridges for wind erosion prevention
-disk: makes small pieces out of large pieces
-chisel: like an arm w/ sharp point, pulled under soil to remove hardpan |
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Term
| What took no till so long? |
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Definition
| -expensive equipment, took time to develop, developed cheap herbicides |
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Term
| What are effects of no till on global warming? |
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Definition
| -increases carbon budget in soil through increased plant/animal life, CO2 from plant growth major holder of gases |
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Term
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Definition
-Bench: sharp rise, 90 degree benches of stone wall separating rows, VERY intensive, move a lot of earth $$$, expose subsoil, require maintenance, harbor pests, not equally spaced so its hard for machinery to get through, rare in present US.
-Steep back-slope:Think of as REALLY WIDE contour, ditches,holds water in LARGE ridge gaps, to remove you can move off laterally to side of field to grassed waterway, expensive way is to install subsurface piping(‘Tiling’) that drains off water underground into harmless place, harbor pests, Better be able to make some $$$!
-Mangum: modern, used on mild slopes, change soil profile, but can go across w/ equipment, although this can wear down terraces and require rebuilding, most common. |
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Term
| Level fields vs. gradient terraces |
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Definition
-usually graded because it's cheaper tahn leveling for removing water
-want it to move laterally w/o eroding terrces, must have minor gradient, enough to move water but not erode soil(0.4%/ max length 2000ft) |
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Term
| how do you space terraces? |
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Definition
| -based on intensity of rainfall & slope percent (plus whatever crop/soil-minor role) |
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Term
| types of grassed waterways? |
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Definition
-triangular cross section/trapezoidal: sharp angle, deeper= more stream power, must be VERY low V-angle to work
-Parabolic: Best option, hard to create w/ straight blade machinery |
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Term
| Types of grass for waterways? |
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Definition
-Bermude is best but very water consumptive.
-constraints: bermuda goes dormant, fescue blooms all winter(good), require watering in dry season.
-Must establish grass before it can become water way, may take several years |
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Term
| How do you construct rocked waterways? |
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Definition
| -Rocked(ripraps): to construction, 1st place fabric down, cover in rock by hand, broken angular pieces that wont wash away, if there's no fabric water flows under rock and can increase erosion, common practice in urban area |
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Term
| What are drop structures? |
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Definition
water pours out of concrete box
-expensive
-concentrates slope below structure, needs proceeding structure to absorb energy
-helpful if done right but not easy
-Common in urban development, roadside ditches. |
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Term
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Definition
-millions in US, form ponds w/ pipe that slowly drains out; pipe height= pond height
-trap sediment
-stabilize channel upstream/downstream b/c flows slower, more uniformly
-stores water for: livestock, irrigation, fishing/recreation, etc |
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Term
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Definition
| soil moves but gets re-deposited, doesn't all leave system. |
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Term
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Definition
A- rural, if broke no damage downstream
B- rural, but damage can occur
C- Serious damage occurs downstream if broken |
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Term
| When were large earthen dams started? |
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Definition
-1966 bill to control erosion/floods
-3 parts: improve land use, ditched streams, BUILD SMALL DAMS |
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Term
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Definition
-they form only when you're doing something wrong, stop doing it and you'll fix the problem
-stop the water, stop the gully
-build earthen dam(most done w/ govt. aid) |
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Term
| How to stop eroding stream banks? |
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Definition
-streams erode outside banks on curves, reshape the bank so there's no curve
-revegetate w/ grass & trees to build sediment
-remove grazing livestock |
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Term
| 4 aspects of water quality for irrigation |
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Definition
-salt concentration: was west water has salt
-proportion of Sodium(disperal) to Ca/Mg(non-dispersal)
-toxic ions: borate, arsenic, chlorine, lithium, selenium
-solid matter: sediment, fills pores, clogs pumps, carries chemicals |
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Term
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Definition
-http://nrcca.cals.cornell.edu/soil/CA3/CA0324.php
-Furrow: bring water in highest part of field that flows down along furrows(entle slope); problems- not enough water= not going far enough down furrow, too much=erosion, overwaters beginning underwaters end.
-Flood: level field w/ dike around it, flood 4-6 inches
-Subsurface: humid climate, drained fields, underground piping of drip system directly to roots.
-Sprinkler: most common, good water application control, doesnt alter land, however expensive equipment
-Center-pivot: huge circles of landscape w/ lock in center rolls around circumference.
-trickle/drip: popular in orchards, little pipes w/ small amount of water used, good water conservation, problem is pipes stop up w/ algae |
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Term
| Major killer of irrigation |
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Definition
SALT- too little water on field= salt build up w/ evap if no "flushing"
-too much: high groundwater table rises up bringing selenium or salts. |
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Term
| Advantages/disadvantages of terraces |
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Definition
Pros: shorten slope length, reduce rill/gully erosion, seeds/plants less damaged by water runoff
Cons: can be more damaging from veriticle falls from one terrace to next, water can sit in channels and keep soils moist reducing crop yieds, |
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Term
| What are underground outlets? |
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Definition
take runoff water from low points in terrace/diversion channel & carry beow ground through pipes to safe discahrge area.
Pros: reduce erosion, sediment fills gullies in areas, peak runoff rates reduced due to detention storage, increased land availability to to lack of nee for vegetated waterway
Cons: COSTLY, can become plugged |
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Term
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Definition
-trap sediment
-stabilize drainage ways
-reduce erosion
-store water in ponds |
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Term
| What is a mining "Spoil"? |
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Definition
| sites near shaft where material is left, can be strongly acidic(pyrite) and toxic |
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Term
| Processes to Reclaiming distrubed land |
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Definition
-balance out pH w/ lime
-loosen if heavily compacted
-recover new topsoil
-revegetate
-apply manure or sewage sludge
-fertilize area |
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Term
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Definition
-divert water from head of gully were most erosion occurs
-smooth slopes on sides
-build temporary dams across to fill with sediment deposits
-establish perennial vegetation
-fence off area from domestic animals |
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Term
| How do you stabilize a streambank? |
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Definition
-Clear channel of large woody debris
-fence off livestock
-establish vegetation
-smooth out curve, meandering |
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Term
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Definition
-high cost
-Spread water-related diseases
-productivity loss caused by increased erosion and EXCESS SALT ACCUMULATION |
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Term
| Types of drainage/Pros & Cons |
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Definition
-Surface:. Surface drainage is accomplished by smoothing out small depressions (land smoothing) or regrading an undulating land surface to a uniform slope, and directing water to a natural or improved, constructed channel.
-Pros:minimize ponded water near crops, and saturated anaerobic soil, best for flat land w/ slow infiltration & low permeability possibly from a restricting soil layer preventing the infiltration of high intensity rainfall.
-Cons: if not done properly soil erosion may occur.
-SUBSURFACE or "Tile" drainage: removal water in subsoil and controlling water table depth below crop root zone. Done by burying plastic or TILE conduits. Must be installed below water table so it will flow into lower energy area.
-Pros: For humid regions the water table can be lowered so poorly drained soils can responed more like well drained, ARID regions minimize buildup of salinty in root zone.
-CONS: $$$ |
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Term
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Definition
-PRO: increase productivity, reclaim soils w/ salt, reduce disease-causing organisms in stagnent water, reduce erosion.
CONS: Lose wetlands/biodiversity, sediment loss, comtaminants spreading |
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Term
| How are impermeable layers formed? |
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Definition
-crusts: caused by impact of raindrops on soil surface, fine particles fil large pores.
-plow layer: continual plowing at same depth, below plow layer soil ge3ts compacted.
-subsoil: caused by heavy machinery traffic. |
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Term
| Susceptibility to compaction: drainage/texture |
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Definition
-Drainage: poorly drained keeps in liquid or plastic state for longer makes susceptible to compaction.
-Texture: high clay content compact easily, dry slowly. |
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Term
| Structural conservations to prevent erosion? |
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Definition
| -grassed waterways -diversion: channels used to intercept surface runoff and divert it to safe discharge site. Used on slopes too steep for terracing. -terraces -drop structures: cement boxes that transfer waer in channel to lower level w/o causing erosion, usually have "plunge pool" below to dissipate flow. |
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