This presentation by Sandeep Bhatti, a master's student at the University of Nebraska-Lincoln, was presented at the Daugherty Water for Food Global Institute’s Research Forum on Thursday, May 11, 2017. Sandeep is a 2016-2017 student support grantee of the Institute.

1. Water and Crop Response
to Variable Rate Irrigation
using Remote Sensing
based Models
Sandeep Bhatti
Burdette Barker
Derek Heeren

2. What are the benefits of adopting
Variable Rate Irrigation at field scale
and at watershed scale?

3. Variable Rate Irrigation (VRI)
• Applying the optimum application depths
of water at both the right time and the
right place
• Site-specific management of water
• Varying water application on different
zones within field due to varying
elevation and soil properties
• Achieved through speed control or zone
control
Speed Control
Zone Control

4. Methodology
• Two center pivot operated fields
under maize and soybean
plantation located at:
• Agricultural Research &
Development Center (ARDC),
Eastern Nebraska
• Brule, Western Nebraska
• Four irrigation treatments applied in 2015 and 2016
• VRI using remote sensing
• VRI using neutron probe
• Uniform
• Rainfed

5. Remote Sensing based Model
• Remote sensing based model was used in VRI using
remote sensing treatment
• Multispectral imagery from Landsat 8 data
• Hybrid Model
• Reflectance-based crop coefficient model
• Two source energy balance model
• Evapotranspiration (ET) estimation through the model
• Spatial ET and soil water modelling helps to manage
irrigation through Variable Rate Irrigation

6. 0
100
200
300
400
ARDC Maize 2015 ARDC Maize 2016 ARDC Soybean 2016 Brule Maize 2016
TotalPrescribedIrrigation(mm)
Site-Crop-Year
VRI-RS VRI-NP Uniform Rainfed
Prescribed Irrigation Comparison

7. Yield Comparison
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE]
[CELLRANGE] [CELLRANGE]
[CELLRANGE]
0
5
10
15
ARDC Maize 2015 ARDC Maize 2016 ARDC Soybean 2016 Brule Maize 2016
Yield(tha-1)
VRI-RS VRI-NP Uniform Rainfed

8. Comparison of Resolution
Imagery from Unmanned Aircraft on 06/17/2016Imagery from Landsat 8 on 06/11/2016

9. Summary
• Adoption of site-specific Variable Rate Irrigation at farm
scale
• Remote sensing based models are used in the study to
create prescription maps through the use of aerial
imagery from satellite and spatial soil water balance
• Unmanned aircraft would be used in future study
• Quantifying benefits of Variable Rate Irrigation over
conventional irrigation
• Making VRI a user friendly technology

10. Outcomes & Outputs
• Outcomes from previous research:
• Yield and prescribed irrigation was compared for the four
treatments
• Over estimation of ET under VRI using Remote Sensing
treatment which led to over estimation of prescribed irrigation
under this treatment
• Outputs to date (started January 2017)
• 1 poster (WFI Conference)

11. Current Study
• Continuation of field research at two Nebraska sites for
two more years
• VRI reduce consumptive use of
water?
• Inclusion of actual soil moisture
content into the model
• Use of unmanned aircraft to
increase temporal and spatial
resolution of imagery

12. Acknowledgements
• Funding through Water for Food Institute
• Continuation of Field Research for two years
• Department of Biological Systems Engineering