The Cross Section, Volume 21, Number 2, February 1975 Page: 4
4 pages : illustrations, mapsView a full description of this periodical.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Page 4 February, 1975 THE CROSS SECTION
ENERGY ... continued from page 3
ing lifts of tailwater return systems
enable irrigation runoff water to be
reclaimed at low energy and invest-
ment costs.
In the past, tailwater or playa lake
pumps powered by natural gas engines
have offered the lowest cost irrigation
water on the Texas High Plains. The
economic advantage of tailwater and
lake pumps increases as the well
pumping lift increases. This compari-
son shows that the pumping lift of
wells must be less than 100 feet before
energy costs are comparable to those
of tailwater return systems. Only a
limited number of irrigation wells on
the High Plains now lift water from
such shallow depths. Pumping depths
of 200 to more than 400 feet are much
more common.
As the water table of the Ogallala
aquifer gradually drops, pumping lifts
increase. Pumping lifts of tailwater
and playa lake pumps are more stable.
Energy requirements increase only
when pump and power unit efficiencies
decrease.
The values of Figure 1 will become
outdated as energy costs change. Any
cost value taken from any pumping
condition curve can be easily updated
using the following formulas.
For natural gas-powered irrigation
wells and lake pumps:
Updated Cost=
Figure 1 value x Current
natural gas cost per Mcf
65 cents per Mcf**
For electric-powered tailwater pumps:
Updated Cost=
Figure 1 value x Current
electricity cost per KWH
1.86 cents per KWH
Updated costs should be representa-
tive since future natural gas engine andelectric motor efficiencies are not likely
to be significantly different from those
used to determine energy costs in this
study.
CONCLUSIONS
In the Texas High Plains the energy
cost for water pumped by tailwater or
playa lake pumps is normally only a
fraction of the energy cost for water
pumped from irrigation wells. The
surface pumps offer a significant eco-
nomic advantage even when compared
to an irrigation well with a pumping
lift of only 100 feet. The amount of
energy required to pump water from
irrigation wells increases as the pump-
ing lift increases. Thus, the energy
cost for pumping most well water willbe at least two to three times greater
than that for pumping from tailwater
pits and playa lakes.
REFERENCES
Power Requirements and Efficiency
Studies of Irrigation Pumps and
Power Units. Agricultural Engi-
neering Department, Texas Tech-
nological College, Lubbock, Texas,
September 1, 1968. 79 pp.
The Irrigation Tailwater Return Sys-
tems Handbook. High Plains Un-
derground Water Conservation Dis-
trict No. 1, Lubbock, Texas. (Draft
in preparation.)
*Agricultural Engineer, U S D A South-
western Great Plains Research Center,
Bushland, and Area Irrigation Specialist,
Texas Agricultural Extension Service, Lub-
bock, respectively.
**The 65-cent figure is low. During the
printing of this issue, the cost rose to 75
cents per Mcf and is expected to rise to
more than $1 per Mcf during the next year
or two.DOLLARS ... continued from page 1
becoming extremely obvious. If you
have already invested $10 per acre-
foot (energy costs only) to lift your
groundwater, an additional cost of only
$1.50 to reuse the water (tailwater re-
turn system energy costs only) would
seem infinitely preferable to additional
pumping of groundwater at $10 per
acre-foot.
As a typical example, an irrigator
wishing to apply six inches of effective
irrigation to 160 acres of land must
pump 96 acre-feet of groundwater
(with no tailwater returned), with an
energy cost (at $10 per acre-foot) of
$960. With a tailwater return system,
he could probably reduce his pumping
to approximately 80 acre-feet for a
primary cost of $800, with an addi-
tional tailwater return energy cost of
$24 for a total energy cost of $834, a
savings of $136 for each six-inch
irrigation.4- 11
>- 10
Co CL
Co =
o LU
W 9
W J
0- C
0 7
-J
S
c-6
3 --
nQ 5
D
-
o2
U 0
c 3
C C
W C
a~1
OLE
00 o400 ft. TDH
300 ft. T '200 ft. :i
100 ft. TDrIrrigation Wells
- --- - -.--y' [-h'' F.r4N
- ii . E;'U.-X TI C1'N"
Figure 1. Represenlatrt energy costs per acreoot for tndlwatrr And play. lake
pumps and for irrigation wells with different pumping heads.INCREASED ... continued from page 3
the moldboarded plots (4,076 pounds
of grain per acre).
These data suggest that, if the farm-
ers did not harvest the crops so as to
create plow soles or hard pans that
would require chiseling or moldboard-
ing to break up, they might save the
cost of such operations and still re-
ceive maximum yields.
It is realized that there are other
considerations such as weed problems
that would cause the producer to con-
sider more intensive tillage operations;
but, if such problems do not exist, a
savings in stored soil moisture with no
decreases in yield may be realized by
eliminating more expensive chiseling
and moldboarding operations.
Adequate Moisture Available
It should be pointed out that there
was adequate moisture for germination
of the crops at three to four inches in
the plots which were shredded, disked
and bedded prior to the rains while
the rains were necessary to provide
moisture for germination in the other
treatments. Thus, producers which
have planting equipment with the
capability or which can be modified to
plant three to four inches below the
top of the bedded soil could be as-
sured of obtaining a stand with stored
moisture in the area with limited till-
age.
Moisture Patterns Similar
The area which was irrigated re-
ceived limited irrigation and was
planted at a later date. The moistureprior to planting followed the same
pattern as the dryland. The more the
area was tilled, the more moisture was
lost. Yields of cotton were not af-
fected by limited tillage but were de-
creagd by moldboarding. In general,
grain *orghum yields were not affected
by iillage except in areas where no
tillag- was done prior to planting
whi4 decreased grain sorghum yields
1,30 pounds of grain per acre.
Research Summarized
In summary, the research indicates
the following:
1) If perennial weeds or hard pans
due to harvesting under wet con-
ditions are not a problem, a
shred-disk-bed operation is ade-
quate to assure maximum yields.
Adequate moisture for crop
establishment would exist with
this tillage practice at three to
four inches if the producer has
Lhe equipment to plant at this
depth.
2) If the land is moldboarded or
chiseled in addition to the shred-
disk-chisel operation, the land
will need to be irrigated, or rain-
[all will be necessary in order to
establish the crops. Based on
water applications at the Lub-
bock Station in 1972, one to two
million acre-feet of water would
he required for preirrigation if
the irrigated land in the Texas
High Plains is moldboarded or
chiseled and if rainfall is not
received.iov6L SVX31 ')13088 1
133IS HN33LAI AS9
I "ON 131HISIG NOllVAa3SNO3
a31VM GNnOUDU3cGNn SNIV-Id HDIHlilNHd SSVl3 CGNO33S
' .
Page 4
February, 1975
T HE CR O SS S EC T IO N
Search Inside
This issue can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Periodical.
High Plains Underground Water Conservation District No. 1 (Tex.). The Cross Section, Volume 21, Number 2, February 1975, periodical, February 1975; Lubbock, Texas. (https://texashistory.unt.edu/ark:/67531/metapth1532999/m1/4/: accessed June 28, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu.; crediting UNT Libraries Government Documents Department.