Dr. Larry C. Brown

Professor, Extension Agricultural EngineerDepartment of Food, Agricultural, and Biological

Engineering

The Ohio State University

Agricultural Water Management brown.59@osu.edu

http://www.ag.ohio-state.edu/~agwatmgt/

Crop Yields

Subsurface DrainageIntroduction

History, Status

Installation

Design

Crop Yields, BenefitsWater Quality - Hydrologic Effects

Management Techniques

ODNR-DSWC Map

USGS

Ohio Soils and Subsurface

Drainage x x

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WW

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USDA-ARS-SDRU/OSU WTM Research Locations

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Drainage Improvement Economics for Corn & Soybean

Toledo Clay – North Central Ohio

Benefits to Cost Ratio

Corn Soybean

Surface Drainage 3.5 2.1

Subsurface Drain 2.5 1.2

Combination 1.9 1.2

(Based on G.O. Schwab Yield Data from Castalia, Ohio)

Yield AdvantageHoytville Silty Clay – Northwest Ohio

Combination Drainage (S+SSD) Compared to Surface Drainage (No SSD)

(bu/ac)

Continuous Corn 25 to 27Rotation Corn 29Rotation Soybean 7 to 10 (17)

(Based on Brown, Reeder & Eckert Yield Data from OARDC, Wood County)

Drainage Improvement Economics for Corn & Soybean

Hoytville Silty Clay – Northwest Ohio

Benefits to Cost RatioContinuous Corn 1.7 to 2.0Rotation Corn 1.7 to 2.2Rotation Soybean 3.1 to 2.3Notes:Combination Drainage (S+SSD) Compared to Surface

Drainage (No SSD)(Based on Brown, Reeder & Eckert Yield Data from

OARDC, Wood County)

Yield Advantage Hoytville Silty Clay - Combination Drainage (S+SSD) Compared to Surface Drainage (No SSD)

Two Long-Term Drainage-Crop Yield Studies

Toledo Silty Clay

(Schwab et al.)

Hoytville Silty Clay

(Brown et al.)

Continuous Corn 25 to 27

Rotation Corn 29

Rotation Soybean 7 to 10 (17)

(Based on Yield Data from Brown, Reeder & Eckert OARDC, Wood County)

Test Case Simulation• Subsurface Drainage Improvement• Hoytville Silty Clay Soil• Drain Spacings of 15, 30, 45 60, and 100

feet• Range of capital costs from $1133/ac to

$150/ac• Down payment, 40% and 20%• MTR 34% and 40%• Cost of debt, 8% and 10%• Price of corn, means of $2.00 and $2.41• Before- and after-tax analyses

Economics of Drainage Improvements

• Simple Field-Scale Analyses

• More Complex Analyses within Farming Enterprise

• Simulation Modeling

Modeling a Water Balance Midway Between Two Subsurface Drains

Predicting Relative Crop YieldsUsing the

DRAINMOD Water Management Model

Kokomo

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12

year

Nu

mb

er o

f d

ays

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60

80

100

120

140

160

PP

T(c

m)

PPT(cm) W T less 30 W T less 60 W T less 90

Crosby

0

5

10

15

20

25

Day

0

20

40

60

80

100

120

140

160

PP

T (

cm

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PPT (cm) WT less 30 cm WT less 60 cm WT less 90 cm

Kokomo Silty Clay Loam – Apparent Water Table, Glacial Till

Crosby Silty Clay Loam – Perched Water Table, Glacial Till

47 Years

Simulation Results

• Optimal spacing 50’

• before-tax analysis

• NPVbt = $928

• Optimal spacing 40’

• after-tax analysis

• NPVat = $818

Water Table Management

• Conventional Drainage

• Controlled Drainage

• Subirrigation

Crop Yields with CWAES @ PRECBrown, Fausey, Bierman, Workman, Subler

156.2

116.6112.7

90.9

114.1121.4

76.9

39.7

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20

40

60

80

100

120

140

160

180

1995 1996 1997 1998

SI/CD

SSD

Partial-season subirrigation in 1995 and 1998 Full-season subirrigation in 1996 and 1997

7.7 in precipitation during subirrigation period in 199613.1 in precipitation during subirrigation period in 1997

44.6

28.8

54.2

43.1

31.2

24.1

26.528.5

0

10

20

30

40

50

60

1995 1996 1997 1998

SI

SSD

Corn Soybean

Yield Advantage (1996-2001) with Subirrigation/Subsurface Drainage

Shininger Farm – Fulton County, Ohio

• Corn• 192 bu/ac SI/SSD• 140 bu/ac SSD

• Six-Year Average Yield advantage

• 52 bu/ac

• Soybean• 63.6 bu/ac SI/SSD• 53.7 bu/ac SSD

• Six-Year Average Yield Advantage

• 9.9 bu/ac

For soils that are proven to respond to drainage improvements, think about more intensity drainage and

management for potential to produce greater yields:

• Compared to lands with adequate surface drainage,– adding subsurface drainage improvements may

increase yields by 25-30 bu/ac for corn and 3-12 bu/ac for soybean

• Compared to lands with adequate surface drainage,– adding subirrigation may increase yields by 25-

60 bu/ac for corn and 10-12 bu/ac for soybean

Ohio State University/USDA-ARS Crop Yield Data

Dr. Larry C. Brown

Professor, Extension Agricultural EngineerDepartment of Food, Agricultural, and Biological

Engineering

The Ohio State University

Agricultural Water Management brown.59@osu.edu

http://www.ag.ohio-state.edu/~agwatmgt/

Shininger Farm Ear Comparison (left SI; right SSD)

Photo by Greg La Barge, 2001