This document summarizes a project to develop smartphone apps for irrigation scheduling of various crops. The project involves researchers from multiple universities who are developing evapotranspiration-based scheduling tools for crops like citrus, cotton, strawberries, and turfgrass. The apps use local weather and soil data, crop coefficients, and information about irrigation systems to provide customized irrigation schedules with minimal user input. Over 400 users have adopted the turfgrass app, and adoption is growing for the other crop apps as well. Field tests show the apps can increase yields while reducing water use compared to traditional scheduling methods.

1. SmartIrrigation Apps
Kati Migliaccio, Clyde Fraisse, Kelly Morgan, George Vellidis
Award number: 2011‐51130‐31143
Project Director’s Meeting, Greensboro, NC 2015

2. Partners
Project Team
 University of Florida
• Kati Migliaccio, Kelly Morgan,
Clyde Fraisse, Jose Andreis,
Diane Rowland, Lincoln Zotarelli
 University of Georgia
• George Vellidis Guy Collins,
Calvin Perry, John Snider, Tim
Cooling, Erick Smith, Wes Porter
 Clemson University
• Jose Payero
 USDA NIFA NIWQ (2011)
 USDA NRCS CIG (2012)
 USDA NIFA NIWQ (2013)
 Cotton Inc.
 Georgia Cotton Commission
 Florida Specialty Crop Block Grant
 Georgia Specialty Crop Block Grant
 Georgia Soybean Commission
 South Carolina Soybean
Commission
Funding

3. Our Goals
 Interactive ET‐based irrigation scheduling tools
 Operate on a smartphone platform
 Can be used to implement both conventional and precision
irrigation across Florida and Georgia
 Cost producers only a few dollars per year provided they have
a smartphone
 Minimum user input
 Ready‐to‐use output
 Engaging – not static

5. Meteorological Data
Crop coefficient approach for estimated ET
where
ETc = estimated crop ET
Kc = crop coefficient
ETo = Penman‐Monteith reference ET (FAO‐56)
KcEToETc 
© iStockphoto.com

6. CropCoefficient(Kc)
1st
Square
1st
Flower
1st
Open Boll

8.  Turf
• Notifications of rainfall and forecasted events
Precipitation
 Citrus
• Irrigation delay based on rainfall
depth
 Cotton
• Provided by station but modified
by grower
 Strawberry
• Not included; plastic mulch with
irrigation everyday

9. Irrigation Systems
 Citrus
 Micro‐sprinkler
 Cotton
 Center Pivot, Drip
 Strawberry
 Plasticulture Drip
 Turf
 Pop‐up Heads
 Apps require system characteristics

10. Soil Water Holding Capacity
 Soils represented by standard classes
(clay, sand, etc.) and/or local soil
names (Gladeland, Krome)
• NRCS data
 Field capacity and wilting point
boundaries used
 No irrigation schedule
recommendation exceeds water
holding capacity
Select the soil
type which best
represents your
field.

11. Irrigation Schedules
 For Citrus, Strawberry, and
Turf only
 Average ET of previous 5 days
 Updated every 15 days unless
ET changes are >50%
 Provided in minutes and/or
irrigation depth

12. 0% Deficit
100% of Available
Soil Moisture
(Full Profile)
50% Deficit
50% of Available
Soil Moisture
(Irrigation Threshold)
75% Deficit
25% of Available
Soil Moisture
(Dry Profile)
Crop
Evapotranspiration
(ETc)
Rain + Irrigation
Soil Profile Water Balance

13. User Interaction – Notifications

16. Other Products
 Extension publications
 Extension in‐service trainings (train the
trainer)
 Commodity/industry
newsletters/magazines (US and
international)
 Extension/conference presentations
 Manuscripts in press and in preparation
 Classroom/student education
 Interest from states in the US and other
countries

18. Adoption
 Strawberry
 13 total users
 35 unique fields
 0 new users in 2015
 0 new fields in 2015
 Turf
 395 total users
 495 unique systems
 92 new users in 2015
 107 new systems in 2015
 Citrus
 53 total users
 115 unique groves
 7 new users in 2015
 32 new groves in 2015
 Cotton
 233 total users
 520 unique fields
 63 new users in 2015
 133 new fields in 2015

19. App Performance
 2013 – Evaluated at Stripling Irrigation Research Park (SIRP)
 Replicated plot studies, one variety
 July and August wetter than normal
 10% higher yield and 75% less water use than the
Checkbook Method
 2014 – Evaluated at SIRP and Tifton
 Replicated plot studies, 4 varieties at each location
 July and August drier than normal
 Approximately same yields as the Checkbook Method with
about 40% less irrigation water
 SEE POSTER

20. Next Steps
 Continued testing and regular improvements
 Evaluate response of producer fields
 Nationalize footprint
 Replace weather station data with other sources
Source: Oregon State PRISM
Climate Group

21. FRET – NOAA’s Forecast of Reference Crop
Evapotranspiration
 Calculated using the Penman‐Monteith Reference Evapotranspiration
Equation and NWS gridded forecasts of temperature, relative humidity,
wind, and cloud cover.

22. More info
Kati Milgiaccio klwhite@ufl.edu
@hydroKati
http://ufifasirrigator.blogspot.com/

23. www.vellidis.org

24. Dr. George Vellidis, Professor
Crop and Soil Sciences Department
University of Georgia
2360 Rainwater Road
Tifton, GA 31793-5766
USA
office: +1.229.386.3442
mobile: +1.229.402.1278
email: yiorgos@uga.edu
www.vellidis.org