Crop choice and irrigation technology decisions: what are the future regional hydrological impacts? Michael Brady and Jon Yoder Bioearth 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 PivotAlfalfaPotatoesDripOrchardVineyard Prob[Irrig|Crop]Alfalfa Center Pivot Wheel LineOrchardDripSprinkler

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 Prices  Crop Change  Irrigation Change  Increase Consumptive Use Increased water scarcity increases the return from investing in more efficient irrigation systems and less water intensive crops. – Less Water  Increase Consumptive Use  Irrigation Change  Crop 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

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 groupCenter pivotDripRillSprinklerWheel line Cereal Grain49,89920%25%0%59%1%14% Hay/Silage41,39616%33%0%7%11%49% Herb33,58413%0%61%29%1%9% Orchard73,80829%0%7%2%92%0% Vegetable12,8305%27%9%52%3%10% Vineyard40,66816%0%37%29%35%0% % by technology 12%16%24%35%13% Total Acres% by crop groupCenter pivotDripRillSprinklerWheel line Cereal Grain66,50123%36%2%47%2%13% Hay/Silage40,56414%37%0%5%12%45% Herb37,92013%2%74%16%0%9% Orchard67,33223%0%7%1%92%0% Vegetable11,3724%26%22%40%3%9% Vineyard38,59813%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 GroupSameDifferentTotal Same9, ,134 71%5% Different2, ,130 19%5% Total11,8961,36813,264 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 ofCenter pivotDripRillSprinklerWheel LineTotal Center pivot Drip81, ,030 Rill682312, ,103 Sprinkler ,455715,835 Wheel Line ,2031,417 Total9682,3662,7595,7801,39113,264 Net change

Net change in crop group and irrigation technology combinations (positive changes in red). Center pivotDripRillSprinklerWheel line Cereal Grain Hay/Silage Herb Orchard Vegetable Vineyard

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.