Joe MasseyDepartment of Plant & Soil Sciences

Mississippi State University

Water-Conserving Irrigation Systems for Furrow Irrigated Soybean and Rice

Grown in the Mississippi Delta

Acknowledgements

• Justin Dulaney(Coahoma Co.)

• Earl Kline(Bolivar Co.)

• Collier Tillman(Leflore Co.)

• Buddy Allen(Tunica Co.)

• Kirk Satterfield(Bolivar Co.)

• Tim Walker(MS DREC)

• Shane Powers(YMD)

• Lyle Pringle(MSU DREC)

• Jim Thomas(MSU ABE ret.)

• Tom Eubank(MSU DREC)

• MAFES

• MS Rice Promotion Board

• MS Water ResourcesResearch Institute

• MS Soybean Promotion Board

• YMD

Collaborators Support

Soybean-Rice Rotation

• Common rotations are 2:1 or 1:1 soybean:rice.

• 2008 crop value: ~$430 million (soybean) and ~$208 million (rice) for the Mississippi Delta.

0

200

400

600

800

1000

1200

1400

1600

1998 2000 2002 2004 2006 2008 2010 2012

Year

Har

vest

ed A

cres

(th

ou

san

ds)

Soybean Acres (Delta only)

Rice Acres

Crop Acres in MS DeltaUSDA NASS (2011)

Avg. Irrigation Water Use (A-ft/A)(YMD, 2010)

0

0.5

1

1.5

2

2.5

3

3.5

4

2000 2002 2004 2006 2008 2010 2012

Year

Ave

rag

e Ir

rig

atio

n W

ater

Use

(A

-ft/

A)

9-yr rice avg = ~3.07 A-ft/A

9-yr soybean avg = ~0.76 A-ft/A

Estimated Irrigation Water Use (A-ft/A)

247,000 A rice @ 100% flood irrigated x 3.07 A-ft/A =

~758,000 A-ft water/yr (rice crop)

1,054,000 A soybean @ 65% irrigated x 0.76 A-ft/A =

~520,000 A-ft water/yr (soybean crop)

Estimated combined rice-soy water use: ~1.3 million A-ft/yr

YMD total water use in 2010: ~2.5 million A-ft/yr

2011 Soybean Phaucet-Optimzed

Furrow Irrigation ResultsTillman FarmHomeplace

Fields A and B

ConventionalDesign

(33.8 A)

Phaucet+ Timer

(40.6 A)

Savings(%)

Water Use(A-inches)

16.8 13.7 22.6

# of Irrigations 4 4 ---

Energy Use(gal/A) (est.)

11.8 9.6 20

Total PumpingTime (hrs)

NA NA NA

Soybean

Yield (bu/A)33.8 42.6 21

Potential Water Savings in Furrow-Irrigated Soybean (A-ft/A)

1,054,000 A soybean @ 65% irrigated x 0.76 A-ft/A =

~520,000 A-ft water/yr (soybean crop)

@ 22% savings via Phaucet = up to ~100,000 A-ft

YMD estimated average overdraft: ~300,000 A-ft/yr

Soybean Phaucet-Optimzed Furrow Irrigation Results

Comments:

MSU Phaucet trials have been conducted on rectangular, relatively ‘uniform’ fields…savings could be greater than 22% on hard-to-water, irregularly-shaped fields, but such fields are hard to study.

Phaucet Comments:

Pump timers may be important to securing savings unless someone will be present to shut-off well when field waters out.

Murphy Switch Brand~$280 each

Grainger Brand Switch~$30 each

Potential Water & Energy Savings in Rice

Pringle (1994) How much water does rice actually need?

Depending on soil and cultivar, rice needs ~14 to 25 inches water (1.1 to 2.1 A-ft/A) per 80-day flood in Mississippi.

Soil Inches per80-d Flood

Sharkey 1.2

Alligator 1.2

Forestdale 3.3

Brittain 3.6

Avg. Deep Percolation Losses Variety Measured

ET (inches)

Rosemont 12.8 ± 3.0

Maybelle 13.6 ± 1.7

Newbonnet 15.7 ± 2.2

Lemont 16.7 ± 2.1

Avg. Evapo-Transpiration Losses

1991 rainfall was 66.5% of avg.1993 rainfall was 97.9% of avg.

ET was linearly-related to biomassproduction

38

905

10152025303540455055

CoutourLevees

StraightLevee(SL)

SL + SideInlet

ZeroGrade

SeasonalRainfall

(A-i

n/A

)

44

38

31

20 9

Total H2O Requirements (ET + Soil Percolation) = ~14 to 25 A-in/A

YMD (2009)6-yr average water use in Mississippi rice production

Pringle (1994): Water Use Requirements for Rice in the MS Delta

Estimated Adoption Rates for Rice Irrigation Systems in MS (2009)

Sources: MSU Extension Service grower surveys; rice consultant surveys; YMD permitting data.

Zero-Grade Rice IrrigationAgronomic Issues Limit Adoption

Drawbacks of Zero-Grade Systems:

1. Water-logging of rotational crops, leading to continuous rice systemswhich can result in

2. Pest management issues (weed resistance; herbicide carry-over) and

3. Loss of yield bump associated with Soy-Rice Rotation

Conversion of 0-Grade to “Ridge-Irrigation” in Tunica Co.

Farmers creating crest in center of 0-grade 40-acre fields to have 0.3-ft fall:

• Rice irrigated as normal for 0-grade.

•Soybean irrigated with tubing placed on ridge down center of field.

Estimated Adoption Rates for Rice Irrigation Systems in MS (2009)

Sources: MSU Extension Service grower surveys; rice consultant surveys; YMD permitting data.

Multiple-Inlet Irrigationin Straight-Levee Systems

Riser

Straight-Levee System

Multiple-Inlet Irrigationin Straight-Levee Systems

Advantages of Side-Inlets:• More rapid flood establishment. • Reduced nitrogen loss.

• Improved herbicide activation.

•Greater control of flood.

• Facilitates adoption of otherwater-saving practices.

MAFES Publication No. 2338 Thomas et al. (2004)

Tacker (2010): Approximate cost = $12/A (tubing + labor)

Estimated Energy Used By Groundwater-Based Irrigation Systems per A-in Water Delivered

State Diesel

(gallons)

Electric(kWh)

per Acre-in water pumped

AR(Tacker)

1 38

LA (Sheffield)

1.1 42

MO(Vories)

0.8 30

MS(Thomas)

0.7 27

Avg. 0.9 gal 34 kWh

For every inch of water not pumped, at least 0.7 gallon/A diesel fuel saved.

38

905

10152025303540455055

CoutourLevees

StraightLevee(SL)

SL + SideInlet

ZeroGrade

SeasonalRainfall

(A-i

n/A

) 38

31

9

38 - 31 in = 7-in water savings (22%) @ 0.7 gal diesel/in = 5 gal diesel/A @ $3/gal = ~ $15/A

Approximate water and fuel savings for adoption of side-inlet in straight-levee system

Less ~$12/A cost of tubingand labor = ~ $2/A net savings

38

905

10152025303540455055

CoutourLevees

StraightLevee(SL)

SL + SideInlet

ZeroGrade

SeasonalRainfall

(A-i

n/A

) 38

31

9

Total H2O Requirements (ET + Soil Percolation) = ~14 to 25 A-in/A

38 - 25-in = 13-in water savings (52%) @ 0.7 gal diesel/in = 9 gal diesel/A saved @ $3/gal diesel = ~$27/A less tubing + labor = $15/A (net)

Approximate water and fuel savings for adoption of side-inlet in straight-levee system

with 25 A-in/A target

Estimated Irrigation Water Use (A-ft/A)

247,000 A rice x 0.45 = 112,500 A straight-levee rice

x ~ 1-ft/A water savings (38 A-in 25-A-in) = ~100,000 A-ft savings

saved by adoption of multiple-inlet irrigation on existing straight-levee fields

Phaucet-optimized savings in soy: Up to 100,000 A-ft

Multiple-inlet rice irrigation savings: Up to 100,000 A-ft

= ~ 2/3 of 300,000 A-ft annual overdraft (potential)

Average Water Use by Different MS Rice Irrigation Systems

05

10152025303540455055

CoutourLevees

StraightLevee (SL)

SL + SideInlet

Intermittent(Dulaney)

ZeroGrade

SeasonalRainfall

(A-i

n/A

)

44

38

31

22 20

SL + Side Inlet + Intermittent

9-yr average @ Dulaney Seed

Average Water Use by Different MS Rice Irrigation Systems

05

10152025303540455055

CoutourLevees

StraightLevee (SL)

SL + SideInlet

Intermittent(Dulaney)

ZeroGrade

SeasonalRainfall

(A-i

n/A

)

44

38

31

21 20

SL + Side Inlet + Intermittent

4-yr average @ Kline Farms

Farmers Extend Savings of Multiple-Inlet Rice Irrigation by:

• Managing flood to increase rainfall capture and to reduce over-pumping.

• Very shallow flooding.

• Managing each paddy as separate production unit.

Flood Management within Each Paddy

Top of Levee

4-in Freeboard for Rain Capture

Top of Levee

Emergency Overflow

~12-inTop of Gate

4-in Controlled Flood

• Irrigate each paddy as needed, not on a schedule.

• Prevent water movement from one paddy to next.

• Keep levels low to capture rainfall.

Multiple-Inlet Irrigationin Straight-Levee Systems

Tacker (2010): Approximate cost = $12/A (tubing + labor)

Total H2O Use = 7.6-in (rainfall) + 18-in (irrigation) = 25.6-in

38

9

05

10152025303540455055

CoutourLevees

StraightLevee(SL)

SL + SideInlet

ZeroGrade

SeasonalRainfall

(A-i

n/A

)

44

38

31

20

9

2011 Rice Irrigation TrialsKline 38-A field, clay soil

Depth Gauges Used to Aid in Flood Management

• Allows rapid determinationof flood status.

• Tillman constructed 200in an afternoon.

Flow Meters used as Management Tool

Permanently Installed Saddle-Type

Flow Meters used as Management Tool

Portable flow meter

Tools & Methods to Efficiently Lay Tubing

Tools & Methods to Efficiently Lay Tubing

Tools & Methods to Efficiently Lay Tubing

Takes a 3-person crew ~1 hour to lay one roll of 10 mil x 15-intubing, install gates, punch air holes, and begin initial flood.

Multiple (Side) Inlet Irrigation is:

A proven, cost-effective flood management tool currently available to MS growers.

Serves as a ‘foundation’ on which greater water and energy savings can be achieved by managing flood to capture rainfalland reduce over-pumping.

Summary

2010 tubing + labor costs: ~$12/A(Tacker, 2010)

Takes a 3-person crew ~1 hour toinstall one roll of tubing incl. gates

(E. Kline; J. Dulaney, 2011)

Summary

Phaucet-optimized savings in soy: Up to 100,000 A-ft

Multiple-inlet rice irrigation savings: Up to 100,000 A-ft

= ~ 2/3 of 300,000 A-ft annual overdraft (potential)

$Systematic Approach to Water and Energy

Conservation in Irrigation of Row Crops

Economics

AgronomicManagement

Crop Breeding

State/FederalRegul

ations

Irrigation Technology

Managing short- vs. longer-term risks