Texas Alliance for
Water Conservation
Dr. Chuck West, Project Leader
Plant & Soil Science Department
Texas Tech University
Ogallala Aquifer
95% of water pumped is used
for irrigation.
Aquifer thought to be an
inexhaustible resource until
about the 1970’s.
Now known to be declining at
rate that far exceeds recharge.
Texas High Plains
20-25% of
the cotton in
the U.S. is
grown in the
40 counties
around
Lubbock, TX.
Corn more
dominant in
northern
Panhandle.
Declining Water Resources
7,000,000
6,000,000
Acres
5,000,000
4,000,000
3,000,000
2,000,000
1,000,000
-
Texas Alliance for Water Conservation
Funded by the Texas Water Development Board
Phase 1 – 2004-2013
Phase 2 – 2014-2019
NRCS & ARS
Texas Tech University

Reduce total water use

Enhance profitability

Identify effective crop and
irrigation systems

Understand and impact
decision-maker behavior
Cotton
Monocultures
Cotton-Cattle
Corn
Cotton
Grass-cattle
Grain Sorghum
Cotton
Specialty Crops
3,000
2,500
Acres
2,000
1,500
1,000
500
0
2005
2006
2007
2008
2009
2010
2011
2012
(4289 ac.) (4230 ac.) (4087 ac.) (3967 ac.) (3991 ac.) (4272 ac.) (4133 ac.) (4732 ac.)
Cotton
Corn - all
Sorghum - all
Perennial forage
Grazed acres
Year (total acres)
Small grains
Other
Sprinkler
Furrow
Sub-surface Drip
Dryland

Rainfall

Temperature

Water applied


Netirrigate ®

PivoTrac ®
Soil moisture

AquaSpy®

Field Connect ®

Production inputs

Plant & animal yields

Economic analysis
Demonstration Topics
 Monitoring soil water content
 Irrigation types
 Differences among crops
 Staggered timing of crop water needs
 Online tools for planning and scheduling
Capacitance probe soil-moisture sensors:
John Deere Field Connect®
AquaSpy® soil capacitance probe
18
4”-20” zones
wetting up
when drip is
turned on.
Rainfall stored
moisture all
the way to 48”
Rainfall
Events
Drip Irrigations
LESA
LEPA
Original
Drag hoses
Furrow dikes
LEPA
Modified bubbler
ability to switch
Modes LESA-LEPA
Comparison of LEPA vs. LESA – 3 years
LEPA
LESA
Cotton lint yield lb/acre
1074
934
Total costs $/acre
958
937
Net returns $/acre
181
57
Water applied inches
19.5
19.5
55
48
WUE
lbs/acre-inch
LEPA Mode
Slower decline with LEPA
Spray Mode
LEPA Mode
Faster wet-up with LEPA
Spray Mode
(Planting Date: 1 May)
Date
(Rajan and Maas)
Daily Water Use (in)
0.4
Boot
Bloom
0.3
Grain Fill
0.2
GPD - 7
leaf
0.1
Maturity
0
0
30
60
Days
90
120
150
Shifting the timing of peak irrigation
Date
(Rajan and Maas)
2005-2011 Averages- includes actual prices and cost
Crop
Yield/acre
Inches
Profit/acre*
Profit/ac-inch
Sorghum
115
7.9
248.30
31.40
Corn
214
17.4
479.40
27.60
Cotton
1275
12.8
336.50
26.30
* Total revenue minus variable field expenses.
Sorghum requires less input per acre.
Example cost per acre below:
(Source: 2013 Texas AgriLife)
 Corn
– 210 bu – 20 inches - $712
 Sorghum – 100 bu – 12 inches -$370
 Cotton
– 1000 lbs – 12 inches - $630
 Produced
= 240.5 bushels/acre
 Total
water supply = 16.9 inches irrigation
and 13.0 inches rain =32.9 inches
 Water
use efficiency = 438 lbs/acre-inch
“Water is Our Future”
 Strategic
planning aid to match crops to
specific fields based on well output.
 Captures
commodity price and production
costs.
 Generates
several options which maximize
net returns/acre.
Tactical planning tool to help decide
 When to irrigate
 How much water to apply
 Specific management goals

Felt they benefitted from involvement in TAWC and
tracking of crop water use and soil water status.

New technologies are complex and expensive.

Before: were unaware of amounts of water applied.
After: became dependent on water monitoring
technologies.

Three types of decision-makers:
a. solely profit motivated.
b. multiple factors motivated, not just profit.
c. traditional, local methods

Influential people:
a. personal network of fellow producers
b. crop consultants to help with technology
Maximizing Water Use Efficiency
The Goal Of Production Agriculture