2014_09_19_seminar_Dr_Perrry_Cabot_can_ag_be_efficient_sustained.pdf
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Transcript of 2014_09_19_seminar_Dr_Perrry_Cabot_can_ag_be_efficient_sustained.pdf
Irrigation Efficiency and ConservationCan agriculture be efficient? Can it be sustained?
2014 Annual Water Seminar: Colorado River DistrictDr. Perry Cabot, Colorado State University
Grand Junction, COSeptember 19, 2014
The three things that we have taken to be the natural state of our water supply –abundant, cheap, and safe – will not be present together in the decades ahead.
We are on the verge of a second modern water revolution.
The Big Thrist (2011)
Fishman, C. 2011. The Big Thirst: The Secret Life and Turbulent Future of Water. Free Press: New York, NY. 2
SOURCE: http://www.nationalgeographic.com/foodfeatures/feeding-9-billion/ 3
Food is critical to our population.
Thank you, Captain Obvious!
Accomplishing this feat will require innovative uses of technology, management (people), natural
resources and policy.
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The basin and statewide dialog deals with how agriculture can contribute (water) to address
existing shortages.
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Two basic strategies:
Conservation and Efficiency
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The terms conservation and efficiency are often used
interchangeably, leading to confusion of methods to address
water shortages.
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Defining these terms is important to correctly inform the societal views
of irrigated farming and its benefits,
… supplying high quality, abundant food to feed our growing population.
Howell, T.A. 2003. Irrigation Efficiency. Encyclopedia of Water Science. Marcel Dekker: New York, NY. pp 467-472. 9
Let’s take a look at conservation.
Conservation is about reducing crop, field or farm water demand.
There will be a downward effect on yields (for similar crops).
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Conservation by row-crop fallowing
Irrigation Water Supply
Consumptive Use
Return Flow
Conserved CU Water
“Saved” Water
Because the crop is gone, fallowing obviously lowers yields.• EXAMPLES: Compensated rotational fallowing, Leasing,
Change of use, Buy-and-Dry+ break disease cycles, soil health, retire marginal lands, shift
the crop mix‒ without proper transition, soil conditions could worsen
Corn Field
Soil Moisture Deficit?
Fallow Field
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Conservation by “deficit” irrigation
Irrigation Water Supply
Consumptive Use
Return Flow
Conserved CU Water
“Saved” Water
For a given yield goal, a conservation approach alone will result in lower yields.• “Doing less with less” (Less yield « » Less diversion)+ foster targeted irrigation to critical growth stages‒ riskier, challenges in water court?
Yield Loss
Alfalfa Field
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Conservation by “split-season” irrigation
Irrigation Water Supply
Consumptive Use
Return Flow
Conserved CU
“Saved” Water
Split-season irrigation is another conservation approach • “Doing less with less” (Less yield « » Less diversion)+ administratively easier because diversion does not take place,
quicker in effectiveness against shortages‒ soil moisture forbearance, nematodes, forage quality
Yield Loss
Alfalfa Field
Soil Moisture?
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Now let’s take a look at efficiency.Efficiency is about reducing water
losses.Conversion of potential benefit into
actual benefit.
Effect on yields should be negligible or even positive.
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Basic Definition: Irrigation Efficiency
Quantitatively, efficiency is the ratio of the volume of water which is beneficially
used to the volume of irrigation water applied.
ASCE. 1978. Describing Irrigation Efficiency and Uniformity. Journal of the Irrigation and Drainage Division. 104: 35–41. 15
Irrigation Concepts
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Efficiency by Tech or Management
Irrigation Water Supply
Consumptive Use
Return Flow“Saved” Water
For a given yield goal, an efficiency approach alone has the goal of maintaining yields.• “Doing the same with less” (Same yield « » Less leakage)+ yields can improve, labor costs lower, change to crop mix,
buffer drought and climate change, water quality improvement‒ higher cost, learning curve, system pressure must support
Alfalfa Field
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Research has already proven that greater efficiencies are entirely possible.
Farmers need reasonable incentives.
Expected Irrigation Efficiencies
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Sprinkler Irrigated Land
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Simple Irrigation Scheduling
• Employ tools for soil moisture monitoring
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Irrigated Corn
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Irrigated Corn
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Conservation versus Efficiency
Efficiency Strategy
Consumptive Use
Return Flow“Saved” Water
Alfalfa Field
Conservation Strategy
Consumptive Use
Return FlowConserved CU Water
“Saved” Water
Yield Loss
Alfalfa Field
No yield loss or increase yield
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Simultaneously practicing conservation and efficiency is possible.
New crops bring new risks.
Alternative Crops or Vanguard Cropping
Consumptive Use
Return Flow
Conserved CU Water
“Saved” Water
For a given yield goal, a conservation approach alone will result in lower yields.• “Doing something different with less” (New « » Less diversion)• Introduces profitability as an issue – what kind of condition are
we trying to maintain? Cash flow? Is there a market?
Alternative Crops
Glennon, R. 2009. Unquenchable: America’s Water Crisis and What to do About it. Island Press: New York, NY. 26
Alfalfa Cropping in California
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Irrigation Scheduling with Telemetry
Saha, R., S. Raghuwanshi, S.K. Upadhyaya, W.W. Wallender, D.C. Slaughter. 2011. Water sensors with cellular system eliminate tailwater drainage in alfalfa irrigation. California Agriculture. 65(4): 202-207. 28
Arnold, B.J., S.K. Upadhyaya, J. Roach, P.S. Kanannavar, D.H. Putnam. 2014. Water advance model and sensor system can reduce tail runoff in irrigated alfalfa fields. California Agriculture. 68(3): 82-88.
Reduced tailwater runoff to 5-10% of applied water
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Onion Farming in the Uncompaghre
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NoChicoBrush (NCB) Site Design
System 1 - Drip
System 2 - Furrow
Base Station
Onion field near Olathe, CO
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Water Budget
Metered Irrigation Monitoring
Tailwater Flume Monitoring
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NoChicoBrush (NCB) Site DataSite Name Acreage Metered Rainfall Irrigation Actual ET
Furrow - Field Corn 1.6 63.1 ac-in 3.7 in/ac 39.4 in/ac 23.8 in/ac
Sprinkler - Field Corn 46 1321.7 ac-in† 3.7 in/ac 28.7 in/ac 23.8 in/ac
Furrow - Onion 1.0 32.1 ac-in 5.0 in/ac 32.1 in/ac 20.8 in/ac
Drip – Onion 28 547.5 ac-in 5.0 in/ac 19.6 in/ac 24.7 in/ac
ASCE (1978) Irrigation efficiency (IE) calculated against Penman-Kimberly ETc (Wright, 1981).• Furrow and Sprinkler IE values for corn fields = 51% vs 70%• Furrow and Drip IE values for onion fields = 50% vs ~99%
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57440
68106
50000
55000
60000
65000
70000
Furrow Irrigation Drip Irrigation
Yiel
d (lb
/acr
e)NoChicoBrush Irrigation Research Sites
(onions planted 4/5/2014)
IWUE (furrow) = 1790 lb in-1
IWUE (drip) = 3774 lb in-1
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0
1000
2000
3000
4000
5000
6000
Colossal Jumbo Medium Pre-Pack
Tota
l Cou
nt
Onion Size Category
NoChicoBrush Irrigation Research SitesFurrow Irrigation Drip Irrigation
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Farming in the Future
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Remote Sensing of ET in Agriculture
Final Thoughts
Twenty years ago, did you think you’d be carrying a phone in your pocket?
How about a computer?
We used to think “the cloud” was just water vapor!
Underlying this technology is the societal trend towards efficiency.
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Eating patterns will likely shift.
The next generation of farmers will be more efficient tech-driven.
In next 50 years, humans must produce as much food as has been produced in history.
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