Finals

36問 • 2年前

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ratio of the average depth of irrigation water infiltrated and stored in the root zone to the average depth of irrigation water applied

application efficiency

rate of evapotranspiration equal to or smaller than predicted ETcrop as affected by the level of available soil water, salinity, field size or other causes

actual crop evapotranspiration

ratio between water received at the inlet for a block of fields to that released at the project’s headwork

conveyance efficiency

ratio of the actual crop evpotranspiration to its potential evapotranspiration

crop coefficient

sequence of different crops grown in regular order on any particular field or fields

cropping pattern

rate of evapotranspiration of a disease-free crop growing in a large field

crop evapotranspiration

the total quantity of water diverted from a stream, lake, or reservoir, or removed from the ground in order to irrigate a crop

diversion water requirement

amount of water used in producing crops which is the sum of evapotranspiration or consumptive use plus seepage and percolation losses

crop water requirement

amount of rainwater that falls directly on the field and is used by the crop for growth and development excluding deep percolation, surface runoff and interception

effective rainfall

combination of water transpired from vegetation and evaporated from the soil, water, and plant surfaces.

evapotranspiration

soil depth from which the bulk of the roots of the crop extracts most of the water needed for evapotranspiration

effective rooting depth

estimation of the chance or likelihood of occurrence of a given event by determining the frequency curves of best fit to samples of hydrologic data

hydrologic frequency analysis

amount of water to replenish the crop water requirement and losses less the effective rainfall

farm water requirement

amount of water required in lowland rice production which is a function of the initial soil moisture and the physical properties of the soil

land soaking water requirement

amount of water required in lowland rice production which includes water losses through evaporation, seepage and percolation and land soaking

land preparation water requirement

rate of water loss by evaporation from an open water surface of a pan

pan evaporation

ratio between reference evapotranspiration (ETo) and water loss by evaporation from an open water surface of a pan

pan coefficient

rate of evapotranspiration from a reference surface which is a hypothetical reference crop with an assumed crop height of 0.2 m, a fixed surface resisteance of 70 s/m and an albedo of 0.23.

reference crop evapotranspiration

vertical flow of water to below the root zone which is affected by soil structure, texture, bulk density, mineralogy, organic matter content, salt type and concentration

percolation

water escaping below or out from water conveyance facilities such as open ditches, canals, natural channels, and waterway

seepage

moisture left in the soil before the initial irrigation water delivery which describes the extent of water depletion from the soil when the water supply has been cut-off

residual moisture content

The physical and chemical suitability, location and supply reliability of water supply shall be assessed

Water supply

Physical characteristics and risk to erosion shall be determined.

Soil

Availability of rainfall and evapotranspiration records near the area shall be determined. Prevailing wind direction and speed shall be known

Meteorological Data

the amount of water the soil profile will hold when all its pore spaces are filled up with water

Saturation Point

a method of determining the appropriate amount of waterto be applied to a crop at the correct time to achieve full crop production potential.

Irrigation Scheduling

the soil moisture content when plants permanently wilt. The soil moisture tension at this point is about 15 atmospheres

Permanent Wilting Point

the amount of water a soil profile will hold against drainage by gravity at a specified time (usually from 24 to 48 hours) after a thorough wetting

Field Capacity

that portion of the available moisture that is most easily extracted by plants

Readily Available Moisture

the difference in moisture content of the soil between field capacity and the permanent wilting point.

Available Moisture

is the amount of water in millimetres that needs to be supplied to the soil in order to bring it back to field capacity.

Net Depth of Application

The allowable portion of available moisture permitted for depletion by the crop before the next irrigation

Allowable Moisture Depletion

is the time it takes a crop to deplete the soil moisture at a given depletion level”

Irrigation frequency

The gross depth of water per irrigation is obtained by dividing the net depth of water (dnet) by efficiency,

Gross Depth of Application

refers to the discharge that has to be abstracted from the headwork during a given period per day and it is used for the design of the headwork and the conveyance system.

System Capacity

is the time it takes to irrigate the entire scheme

Irrigation Cycle

Soil Tech Midterm 1

Mutated Lemon · 100問 · 2年前

Soil Tech Midterm 1