Post on 01-Jan-2016
description
transcript
Crop choice and irrigation technology decisions: what are the future regional
hydrological impacts?
Michael Brady and Jon YoderBioearth Integration Seminar
Research Questions/Ideas
• How do previous decisions constrain changes in crop and irrigation technologies?
• What is the impact of changes in cropping patterns on consumptive use via irrigation technology?
• What is the impact of increased water scarcity on crop choice?
• Forecast 10, 20, or 30 years ahead the effect of changes in food market conditions (e.g. prices, trade) on water scarcity in the Yakima Basin.
Prob[Crop|Irrig]
Center Pivot
Alfalfa
Potatoes
Drip
Orchard
Vineyard
Prob[Irrig|Crop]
Alfalfa
Center Pivot
Wheel Line
OrchardDrip
Sprinkler
Direction of effect goes both ways
• More rapid crop change may increase consumptive use because it allows producers to change their irrigation delivery system (technology). – Relative Crop PricesCrop Change Irrigation
ChangeIncrease Consumptive Use
• Increased water scarcity increases the return from investing in more efficient irrigation systems and less water intensive crops.– Less WaterIncrease Consumptive UseIrrigation
ChangeCrop Change (perhaps)
Previous Research• A lot of work done in California, but also in the Great Plains (fewer crop choices).
• Aggregate data:– Higher water cost increases the likelihood of adopting more efficient irrigation technology (Caswell and
Zilberman, 1985).– Land quality influences technology choice to a greater extent than water cost (Negri and Brooks, 1990).
• Field-level, single cross-section:– Assuming technology choice is conditional on crop choice, Green and Sunding (1997) find that the relative
influence of land quality and water cost varies by perennial crop type.
• Field-level, panel data set:– Moreno and Sunding (2005) estimate a model that allows them to drop the sequential assumption. Results
point towards financial drivers for increased water use efficiency as the dominant factor. – Kandouri et al. (2006) introduce uncertainty over water availability in drought years into decision making.
Studying farmers in Crete, find that risk management is important factor influencing irrigation technology choice.
• **I have not found an example of an empirical economic analysis linked with an engineering model to forecast basin-wide hydrological impacts of increased consumptive use driven by economic factors (relative profitability of each crop and return on investment in more efficient irrigation system).
Construction of field-level panel data set for the Yakima Basin from 2007 to 2011 using the WSDA data
Cowlitz
Palouse
Lewis
Lower Crab
Lower Yakima
Soleduc
KettleNooksack
Pe
nd O
reill
e
Upper Crab-Wilson
Esquatzel CouleeUpper Chehalis
Queets-Quinault
Puyallup-White
San Juan
Lower Spokane
Elwha-Dungeness
Lower Snake
Grand Coulee
Stillaguamish
Alkali-Squilchuck
Middle Lake Roosevelt
Little Spokane
Hangman
Wind-White Salmon
Quilcene-Snow
Cedar-Sammamish
Duwamish-Green
Lower Skagit / Samish
Grays/Elochoman
Deschutes
Skokomish-Dosewallips
Upper Lake Roosevelt
Salmon-Washougal
Lower Lake Roosevelt
Nespelem
Middle Spokane
Kennedy-Goldsborough
Fields sampled by year
2011 2010
20092008
2007
Irrigated LCC (1=most fertile)
1
2
3
4
5
6
7
NRCS Irrigated Land Classifications
Year t+1 Field Boundary (red)
Year t Field Boundary (black)
Year t+1 Field Centroid (red)
Panel is created by spatially joining points in year t+1 with polygons in year t because field boundaries change over time.
Total Acres % by crop group Center pivot Drip Rill Sprinkler Wheel lineCereal Grain 49,899 20% 25% 0% 59% 1% 14%Hay/Silage 41,396 16% 33% 0% 7% 11% 49%Herb 33,584 13% 0% 61% 29% 1% 9%Orchard 73,808 29% 0% 7% 2% 92% 0%Vegetable 12,830 5% 27% 9% 52% 3% 10%Vineyard 40,668 16% 0% 37% 29% 35% 0%% by technology 12% 16% 24% 35% 13%
Total Acres % by crop group Center pivot Drip Rill Sprinkler Wheel lineCereal Grain 66,501 23% 36% 2% 47% 2% 13%Hay/Silage 40,564 14% 37% 0% 5% 12% 45%Herb 37,920 13% 2% 74% 16% 0% 9%Orchard 67,332 23% 0% 7% 1% 92% 0%Vegetable 11,372 4% 26% 22% 40% 3% 9%Vineyard 38,598 13% 0% 45% 16% 39% 0%% by technology 16% 20% 19% 32% 12%
Irrigation acreage share by crop group and irrigation technology for 2007
Irrigation acreage share by crop group and irrigation technology for 2011
• For perennials, increase in vineyards and decrease in orchards.• Much greater share of cereal grains irrigated by center pivot and less using rill. • Orchard irrigation stayed the sum, BUT orchard acreage shrank.• Greater share of vineyards irrigated by drip versus sprinkler because new
ground was planted in vineyards.
Irrigation technology
Crop Group Same Different Total
Same 9,435 699 10,134
71% 5%
Different 2,461 669 3,130
19% 5%
Total 11,896 1,368 13,264
Crop group and irrigation technology adoption by observation (field, not area).
• 13,264 observations is the number of fields that were resampled from 2008 to 2011 where 2007 is the first year with data.
• Almost 30% changed either crop or technology.
• As expected, change in cropping more common than irrigation.
• 10% change in irrigation which could be significant over time.
Irrigation technology transitions
Transitioned into
Transitioned out of Center pivot Drip Rill Sprinkler Wheel Line Total
Center pivot 842 4 16 7 10 879
Drip 8 1,878 58 74 12 2,030
Rill 68 231 2,518 191 95 3,103
Sprinkler 13 196 100 5,455 71 5,835
Wheel Line 37 57 67 53 1,203 1,417
Total 968 2,366 2,759 5,780 1,391 13,264
Net change 89 336 -344 -55 -26
Net change in crop group and irrigation technology combinations (positive changes in red).
Center pivot Drip Rill Sprinkler Wheel line
Cereal Grain 106 24 21 6 16
Hay/Silage 16 0 -48 -30 -83
Herb 5 203 -80 -1 12
Orchard 0 13 2 -227 -2
Vegetable -26 31 -79 9 -8
Vineyard 1 64 -153 29 2
Cereal Grain Hay/Silage Herb Hops Mint Non-Crop Orchard Unknown Vegetable Vineyard0
1,000
2,000
3,000
4,000
5,000
6,000
Annual Change in Crop Group/Irrigation Technology
diff/diff diff/same
same/diff same/same
Original Crop Group
Obs
erva
tions
Cereal
Grain
Hay/Si
lage
Herb HopsMint
Non-Crop
Orchard
Unknown
Vegeta
ble
Vineyard
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Annual % Change in Crop Group and Irrigation Technology
diff/diff
diff/same
same/diff
same/same
Original Crop Group
Moving forward...
• Finish empirical economic analysis of historical data (possibly one paper). – Estimate influence of crop prices, growing conditions,
and other factors on choice.
• Forecast basin-wide hydrological impacts of future changes in cropping and irrigation technology (integrated economics-CropSyst/VIC). – Forecast future crop/irrigation pattern as a function of
future prices and water scarcity.