Agriculture Reference
In-Depth Information
Wa t er in
Water stored
i.e., flow rate
=
×
application time
=
Furrow cross-sectional area
×
average depth
of water
i.e.,
q
×
t
=
A
×
d
=
(
W
×
L
)
×
d
q
×
t
Or,
d
=
(3.23)
W
×
L
where
q
flow rate in individual furrow, m
3
/s
=
t
=
time, sec (s)
W
=
width of furrow, meter (m)
L
=
length of furrow, m
3.4.10 Suggestions for Improving Furrow Irrigations
•
Always look to measure and improve distribution uniformity (DU) first. Water
must infiltrate as evenly as possible across a field. Then, try to improve control
over the total infiltration and reduce or reuse surface runoff.
•
Utilize an irrigation scheduling system so that you have reasonably accurate
estimates of “WHEN” and “HOW MUCH” to irrigate.
•
Reduce the length of the furrow - it improves down row uniformity by helping
water to get to the end of furrow quicker in relation to the total time of irrigation.
•
Install a “tailwater” reuse system - it improves overall irrigation efficiency by
saving “tailwater” for reuse.
•
Increase the flow per furrow - it improves down row uniformity by helping water
to get to the end of the furrow quicker in relation to the total time of irrigation.
•
Irrigate in every other furrow - this helps to reduce overapplication when either
small irrigations are desired or the soil has a high infiltration rate.
•
Use cutback furrow flows - it reduces the amount of surface runoff.
•
Utilize surge irrigation - this might occur from three times to as many as 10
depending on the situation, equipment, and experience. Surging water acts to
reduce the infiltration rate of the soil quickly so that differences between com-
pacted and uncompacted furrows are minimized. It can also help in very light
soils as it will act to reduce overapplications.
3.4.11 Furrow Irrigation Models
3.4.11.1 FURDEV
FURDEV is a software tool for furrow irrigation system design and evaluation. The
FURDEV software package is based on the solution of the volume balance model
(Zerihun and Feyen, 1996 BORDEV: BORder Design management and Evaluation
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