Soil Tech Finals 2

46問 • 2年前

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aims to identify those areas of land where the maximum sustained productivity From a given land use

Erosion hazard assessment

is defined as the lowering of the soil's capacity to support human life.It is also described as the destruction and deterioration of the physical, chemical, and biological properties of the soil

Soil degradation

is a worldwide phenomenon leading to loss of nutrient rich surface soil, increased runoff from more impermeable subsoil and decreased water availability to plants

Degradation of agricultural land by soil erosion

is the portion of rainfall that makes its way toward stream channels, lakes, or oceans as surface or subsurface Flow. However, runoff usually refers to overland or surface Flow

Runoff

FACTORS AFFECTING RUN-OFF

PRECIPITATION, WATERSHED FACTORS, TOPOGRAPHIC FEATURES, VEGETATION AND MANAGEMENT PRACTICES

was developed by the United States Natural Resources Conservation Service as a method of assessing the extent to which limitations such as erosion, soil depth, wetness and climate hinder the agricultural use that can be made of the land.

Land capability classification

soils have few limitation restricting their use.

Class I soils

have some limitations that reduce the choice of plants or require moderate conservation practices

Class Il soils

have severe limitations that reduce the choice of plants or require special conservation practices

Class III Soils

have very severe limitations that restrict the choice of plants and or require very careful management

Class IV soils

have few or no erosion hazards but have other limitations impracticable to remove, that restrict their use to pasture or range, woodland, or wildlife Food cover

Class V soils

have severe limitations that make them generally unsuited to cultivation and limit their use largerly to pasture or range woodland, or wildlife food cover.

Class VI soils

have very severe limitations that make them unsuited to cultivation and also, restrict their use largely to grazing, woodland or wildlife

Class VII soils

soils and land Forms have limitations that preclude their use for commercial plant production.

Class VIII

SUB-CLASSES

E, W, S, C

E stands for

EROSION

W stands for

WETNESS, DRAINAGE OR OVERFLOW

S stands for

ROOTING ZONE LIMITATIONS (SHALLOW OR DROUGHTY)

C stands for

CLIMATIC LIMITATION

sand and gravel in sub-stratum

erosion hazard

wetness by poor drainage

slow permeability

coarse textured or excess gravel

Fine or very fine texture

salts or alkali

cobblestone, stone or rock

hard pan or near impervious bedrock

low fertility or toxicity

IS EXPRESSED AS A QUANTITY PER UNIT AREA AND TIME AND OFTEN APPLIES TO SMALL PLOTS

SOIL LOSS

REFERS TO THE AMOUNT OF ERODED MATERIAL THAT PASSES A DESIGNATED POINT AT THE OUTFLOW END OF A PLOT, FIELD. CHANNEL, OR WATERSHED

SEDIMENT YIELD

This method of estimating soil loss was developed from 1945 to 1965 based on statistical analyses of field plot data from small plots in many states in the U.S.

The Universal Soil Loss Equation

is useful for determining conservation measures' adequacy in farm planning and predicting non-point sediment losses.

The Universal Soil Loss Equation

USLE FACTORS

R, K, LS, C, P

REPRESENTS THE EROSION POTENTIAL, BASED ON THE RAINFALL AND RUNOFF BY GEOGRAPHIC LOCATION.

R factor

IS THE FLOW OF WATER ON THE GROUND WHEN IT CANNOT RAPIDLY INFILTRATE THE SOIL

RUNOFF

IS THE SOIL ERODIBILITY FACTOR.

K factor

IS PRIMARILY INFLUENCED BY SOIL TEXTURE, BUT IT CAN ALSO BE IMPACTED BY STRUCTURE, ORGANIC MATTER, AND PERMEABILITY.

K factor

REPRESENTS SOIL LOSS DEPENDENT ON SLOPE STEEPNESS AND LENGTH. THE STEEPER AND LONGER THE SLOPE, THE GREATER THE RISK OF SOIL EROSION.

LS factor

COMBINES SOIL LOSS FROM A SPECIFIC CROP AND SOIL LOSS FROM A SPECIFIC LAND MANAGEMENT TECHNIQUE

C factor

REPRESENTS HOW AN AGRICULTURAL SUPPORT PRACTICE WILL AFFECT SOIL LOSS.

P factor

V factor

the vegetative cover Factor

L factor

the unsheltered distance

C factor

climatic factor

K factor

soil surface roughness factor

I factor

soil erodibility index

Soil Tech Midterm 1

Mutated Lemon · 100問 · 2年前

Soil Tech Midterm 1