ABE 1-CWR

Question 1

defined as the depth of water needed to meet the water consumed through evapotranspiration by a disease-free crop,
growing in large fields under non-restricting soil conditions including soil water and fertility, and achieving full production potential under the given
growing environment

Answer 1

Crop water requirements (CWR)

Question 2

rate of evapotranspiration of a given crop as influenced by
its growth stages, environmental conditions and crop management to achieve the potential crop production

Answer 2

crop evapotranspiration (ETc)

Question 3

sum of ETc for the entire crop
growth period

Answer 3

CWR

Question 4

When management or environmental conditions
deviate from the optimal, then that rate of evapotranspiration has to be adjusted to the prevailing conditions and is called ________________________

Answer 4

-actual crop evapotranspiration (ETc)

Question 5

-the property of plants used in predicting actual evapotranspiration
-value varies with the
development stages of the crop

Answer 5

Crop Coefficient (kc)

Question 6

Date of sowing

Length of the total growing season

Duration of the initial stage (germination to 10% ground cover)

Duration of crop development stage (from 10% to 80% ground cover)

Duration of the mid season stage (from 80% ground cover to start of
ripening)

Duration of the late season stage (from start of ripening to harvest)

Answer 6

Information required on crops

Question 7

Both ______and _____ concepts apply to either irrigated
or rainfed crops.

Answer 7

-CWR
-ETc

Question 8

For irrigated crops, the concept of CWR has to be
complemented by that of ____________________

Answer 8

irrigation water requirement (IWR)

Question 9

-is the net depth of water [mm] that is required to be applied to a crop to fully satisfy its specific crop water
requirement.

-It is the fraction of CWR not satisfied by rainfall, soil
water storage and groundwater contribution

Answer 9

irrigation water requirement (IWR)

Question 10

-defined as the quantity or depth of irrigation water in
addition to precipitation required to produce the desired crop yield and quality and to maintain an acceptable salt balance in the root zone (NEH, 2003)

-strongly influenced by the amount and timing of
precipitation

Answer 10

Irrigation water requirements

Question 11

USES of __________________-

irrigation scheduling for a specific field

seasonal water needs for planning, management, and
development of irrigation projects

Answer 11

Irrigation water requirements

Question 12

-A procedure to record the additions and withdrawals of
water from the crop root zone and to determine the amount of available water remaining in the root zone at a desired time
-In flooded areas, the capillary rise is usually neglected because of the continuous percolation from the puddled layer

Answer 12

SOIL WATER BALANCE

Question 13

Δ moisture in the soil =

Answer 13

input – output

Question 14

is a critical measure of irrigation performance in terms of the water required to irrigate a field, farm, basin, irrigation district, or an entire watershed.

Answer 14

Irrigation efficiency

Question 15

is a basic engineering term used in irrigation science to characterize irrigation performance, evaluate irrigation water use, and to promote better or improved use of water resources, particularly those used in agriculture and turf/landscape management.

Answer 15

Irrigation efficiency

Question 16

Irrigation efficiency is a function of the following:

Answer 16

-irrigation method used

-physical condition of the irrigation system

-physical condition of the soil

-plant or crop type, spacing and population

-timing and amount of irrigation water applied

-water management level and skill

-environmental condition at the time water is applied

Question 17

economics of irrigation

amount of water needed to irrigate a specific land area

spatial uniformity of the crop and its yield

amount of water that might percolate beneath the crop root
zone

amount of water that can return to surface sources for
downstream uses or to groundwater aquifers that might supply other water uses

amount of water lost to unrecoverable sources (salt sink, saline aquifer, ocean, or unsaturated vadose zone).

Answer 17

Things that affects Irrigation efficiency

Question 18

The ratio between the water delivered to the farm and the water diverted from a river or reservoir expressed in percent

Ec = (Wf / Wr) x 100

where:

Wf = water delivered to the farm

Wr = water diverted from the river or reservoir

Answer 18

Water conveyance efficiency (Ec)

Question 19

-result primarily from Seepage from ditches, canals, and pipelines

-Leakage through and around headgates and other structures

-Operational spills

Answer 19

Conveyance losses

Question 20

Some loss in conveyance is ___________.

Answer 20

unavoidable

Question 21

Losses may be greatly reduced by (1) lining earth ditches and canals or converting to pipelines and (2) by repairing and maintaining canals and pipelines, headgates, and other structures

Answer 21

Some loss in conveyance is unavoidable.

Question 22

The ratio between water stored in the soil root zone during irrigation and the water delivered to the farm expressed in percent

Ea = (Ws / Wf) x 100

where:

Ws = water stored in the soil root zone during irrigation

Wf = water delivered to the farm

Answer 22

Water application efficiency (Ea)

Question 23

A concept that combines a measure of uniformity and Ea and provides for adequacy considerations

Answer 23

Application Efficiency of the Low Quarter (AELQ) or the Application Efficiency of the Low Half (AELH).

Question 24

ratio of the average of the lowest one-fourth of measurements of irrigation water infiltrated to the average
depth of irrigation water infiltrated, expressed as a percentage.

Answer 24

AELQ

Question 25

ratio of the average of the low one half of
measurements of irrigation water infiltrated to the average depth of irrigation water

Answer 25

AELH

Question 26

A measure of the uniformity of irrigation water distribution over a field

Answer 26

Water distribution efficiency (Ed)

Question 27

Methods to compare the uniformity of water application between different irrigation methods and systems

Answer 27

-distribution uniformity (DU) for the average low-quarter or low-half depth
-Christiansen coefficient of uniformity (CU)

Question 28

is the ratio of the average of the lowest one-fourth of measurements of irrigation water infiltrated to the average depth of irrigation water infiltrated, expressed as a percentage

Answer 28

DU of low one-quarter

Question 29

is the average of the lowest one-quarter of all measured values each of which
represent an equal area of the field

A similar definition is used for high quarter depth and low half depth

Answer 29

Average low-quarter depth of water infiltrated

Question 30

also use to evaluate application uniformity

Answer 30

Christiansen’s coefficient of unformity (CU)

Question 31

When CU is greater than 70%, test data typically form a _________________ that is normally distributed and symmetric about the mean

Answer 31

bell shaped curve

Question 32

The ratio of water beneficially used on the project, farm or field to the amount of water delivered to the farm expressed in percent

Answer 32

Water use efficiency (Eu)

Question 33

The ratio of water stored in the root zone during the irrigation to the water needed in the root zone prior to irrigation, expressed in percent

Answer 33

Water storage efficiency (Es)

Question 34

The ratio of the normal consumptive use of water to the net amount of water depleted from the root zone

Answer 34

Consumptive use efficiency (Ecu)