North Central Region One Water Action Forum

1. Yield Benefits of Drainage
Water Recycling in Iowa and
Indiana
Chris Hay, Iowa Soybean Association
Ben Reinhart, Jane Frankenberger, Laura Bowling, Purdue University
Matthew Helmers, Iowa State University

2. Drainage water recycling

3. Managing Water for Increased Resiliency of
Drained Agricultural Landscapes

6. Feasibility
Demand Supply
Impact

7. Supply and demand in Iowa

8. Soybean NIR (mm)

9. Corn NIR (mm)

10. Gilmore City mean drainage depth was 226 mm

11. Drainage peaks in May and June

12. CO2
Solar radiation
Temperature
Genotype
Crop canopy
Attainable
yield with
available
water supply
(rainfall,
irrigation)
Limit factors:
Water
Nutrients
Weeds
Pests
Others

14. Number of years irrigation required
(out of 23)

15. Irrigation depth required

16. Potential corn yield impact of irrigation
ranged from 1.4 to 4.0 Mg/ha

17. Field data in
IN (DPAC)
and IA (SERF)
(2007-2016, daily)
• Drain flow
• Water Table
• On-site climate
DPAC (Saadat, Bowling,
Frankenberger), SERF
(Helmers)
Slide courtesy of Ben Reinhart, Purdue University

18. Modeling the field and reservoir water
balances
Slide courtesy of Ben Reinhart, Purdue University

19. 10%
8%
6%
4%
2%
Slide courtesy of Ben Reinhart, Purdue University
Average depth of 3.05 m

20. Mean DPAC yield gap was 3.2 Mg/ha
102 102 102 25 76 76 76 25 0 0

21. Mean SERF yield gap was 2.7 Mg/ha
0 0 0 0 127 127 152 0 0 25

24. In summary:
• Irrigation requirement in 12
to 20 years out of 23
• Generally adequate
drainage water to meet
demand
• Results suggest potential
yield impacts of up to 1.4 to
4.0 Mg/ha
• Reservoir area of 4 to 6%
could meet irrigation
demand
Questions?