Impacts of 4R Management on Drainage Water Quality · Matt Helmers – Director of the Iowa Nutrient Research Center, Professor in Dept. of Ag. And Biosystems Engineering and Dean’s

College of Agriculture and Life Sciences

Impacts of 4R Management on Drainage Water Quality

Matt Helmers – Director of the Iowa Nutrient Research Center, Professor in Dept. of Ag. And Biosystems Engineering and Dean’s Professor in the College of Ag and Life Sciences

NWRF Drainage NERF Drainage

COBS

SERF Drainage

Replicated subsurface drainage plots to evaluate performance of various in-field management practices

Gilmore City DRF

172 monitored plots~4000 samples per year

Subsurface Drainage Layout

Flow Monitoring System


COBS

SERF Drainage


Gilmore City DRF

Twenty-Nine Year Summary

199019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

0620

0720

0820

0920

1020

1120

1220

1320

1420

1520

1620

1720

18Avg

Dra

inag

e (in

)

0

5

10

15

20

25

30

Nitr

ate-

nitro

gen

Con

cent

ratio

n (p

pm)

0

5

10

15

20

25

30

Nitr

ate-

nitro

gen

Loss

(lb-

N/a

c)

0

20

40

60

80

100

120DrainageNitrate-N ConcentrationNitrate-N Loss

Corn-Soybean Rotation 150/160 lb-N/acre Application Rate

Twenty-Nine Year Summary

199019

9119

9219

9319

9419

9519

9619

9719

9819

9920

0020

0120

0220

0320

0420

0520

0620

0720

0820

0920

1020

1120

1220

1320

1420

1520

1620

1720

18Avg

Dra

inag

e (in

)

0

5

10

15

20

25

30

Nitr

ate-

nitro

gen

Con

cent

ratio

n (p

pm)

0

5

10

15

20

25

30

Nitr

ate-

nitro

gen

Loss

(lb-

N/a

c)

0

20

40

60

80

100

120DrainageNitrate-N ConcentrationNitrate-N Loss

Corn-Soybean Rotation 150/160 lb-N/acre Application Rate

Combined Corn-Soybean System – Same N management – Early Spring Sidedress at 150-160 lb-N/acre

N-Rate versus Concentration

N Application Rate (lb/acre)

0 50 100 150 200 250 300

Nitr

ate-

N C

once

ntra

tion

(mg/

L)

0

5

10

15

20

25

30

Timing Study at ADW


COBS

SERF Drainage


Gilmore City DRF

Treatments

Treatment Number Tillage Nitrogen Application

Time

Nitrogen Application Rate

(lb N/acre)*1 Conventional tillage* Fall (anhydrous

ammonia with nitrapyrin)**

135

2 Conventional tillage Spring (anhydrous ammonia)

135

3 Conventional tillage Split with variable N at sidedress (40 lb/acre of

urea 2x2 starter at planting plus in-season agrotain treated urea)

135

4 Conventional tillage None 0

* Fall chisel corn stalks with spring disk/field cultivate, and spring disk/field cultivate soybean stubble.**In fall of 2014 freezing conditions occurred early and prevented fall application. Application occurred in early spring 2015.

Corn Yield

*Means with the same letter in the same year are not significantly different, P=0.05.

2015

Fall N

Spring

NSpli

t NNo N

Cor

n Yi

eld

(bu/

acre

)

0

50

100

150

200

250

2016

Fall N

Spring

NSpli

t NNo N

Cor

n Yi

eld

(bu/

acre

)

0

50

100

150

200

250

a a ab

a a a

b

Fall N

Spring

NSpli

t NNo N

Cor

n Yi

eld

(bu/

acre

)

0

50

100

150

200

250

a a b

c

2017

Fall N

Spring

NSpli

t NNo N

Cor

n Yi

eld

(bu/

acre

)

0

50

100

150

200

250

a a a

b

2018

Soybean Yield


2015

Fall N

Spring

NSpli

t NNo N

Soyb

ean

Yiel

d (b

u/ac

re)

0

20

40

60

80

2016

Fall N

Spring

NSpli

t NNo N

Soyb

ean

Yiel

d (b

u/ac

re)

0

20

40

60

80

2016

Fall N

Spring

NSpli

t NNo N

Soyb

ean

Yiel

d (b

u/ac

re)

0

20

40

60

80

2017

Fall N

Spring

NSpli

t NNo N

Soyb

ean

Yiel

d (b

u/ac

re)

0

20

40

60

80

2018

Flow-weighted Nitrate-N Concentration

*Means with the same letter in the same year are not significantly different, P=0.05. Analyzed across corn and soybean phase

Fall N

Spring

NSpli

t NNo N

Flow

-wei

ghte

d N

itrat

e-N

Con

c. (m

g/L)

02468

1012141618

Corn Phase - 2015-2018a ab

dc de

Fall N

Spring

NSpli

t NNo N

Flow

-wei

ghte

d N

itrat

e-N

Con

c. (m

g/L)

02468

1012141618

Soybean Phase - 2015-2018

bcab

dce


COBS

SERF Drainage


Gilmore City DRF

Management Systems for 2008-2015 Study

Treatment Timing and source of N

Target N Rate kg ha-1

Crop rotation Tillage

SU168 Spring UAN-

168-

CornSoybean

Chisel plow corn fallField cultivate spring

SU168NT+R Spring UAN-

168-

Corn + Rye cover cropSoybean + Rye cover crop

No-TillNo-Till

FM168 Fall Manure-

168-

CornSoybean


FM168/112 Fall ManureFall Manure

168112

CornSoybean


FM168NT Fall Manure-

168-

CornSoybean

No-TillNo-Till

FM224CC Fall ManureFall Manure

224224

Continuous Corn Chisel plow fall Field cultivate spring

FM224CC-S Fall ManureFall Manure

224224

Continuous Corn withStover removal

Chisel plow fall Field cultivate spring

Nitrate-N Loss from 2008-2015

No-till

Till

Management systems for 2016 - 2018 studySystem Application timing and N

sourceCrop Tillage N rate

(lb/ac) 1 Spring UAN

-Corn

SoybeanChisel plow

Field cultivate150

-2 Early fall manure

-Corn

SoybeanNo-tillNo-till

150-

3a Late fall manure + Instinct Continuous corn Chisel plow 200

3b Spring manure Continuous corn Chisel plow 200

4a Late fall manure Continuous corn Chisel plow 200

4b Late fall manure + 1 ton/ac gypsum

Continuous corn Chisel plow 200

5 Early fall manure-

Corn + Rye coverSoybean + Rye cover

No-tillNo-till

150-

6 Late fall manure-

CornSoybean

No-tillNo-till

150-

Research funded by Iowa Pork Producers Association and Calcium Products Inc.

Corn phase: Flow-weighted Nitrate-N Concentration


2016

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

a

c c

b

2017

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30a

c c

b

2018

UAN

Early M

an

Early M

an +

CC

Late

Man

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

aa

a a

Soybean phase: Flow-weighted Nitrate-N Concentration


2016

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

aa

b

a

2017

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

ab

a

c

b

2018

UAN

Early M

an

Early M

an +

CC

Late

Man

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

bc

a

c

ab

Continuous Corn: Flow-weighted Nitrate-N Concentration


2016

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

aaa a

2017

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

aba a a

2018

Late

Man +I

n

Spring

Man

Late

Man

Late

Man +

Gyp

Annu

al N

itrat

e- N

Con

cent

ratio

n (m

g/L)

0

5

10

15

20

25

30

aa a

a

Corn phase yields

-26 bu

+27 bu

+5 bu

+64 bu

+16 bu

+29 bu


Soybean phase yields

-12 bu

-3 bu+1 bu


Continuous corn yields

*+37 bu

*LFM200+I was planted to soybeans in 2015

+12 bu+29 bu

24

+20 bu

+50 bu



COBS

SERF Drainage


Gilmore City DRF

Impact of Land Management


COBS

SERF Drainage


Gilmore City DRF

Temporal Changes

Corn Yield

1990

1995

2000

2005

2010

2015

Cor

n Yi

eld

(bu/

acre

)

100

120

140

160

180

200

N Output with Grain

1990

1995

2000

2005

2010

2015

N O

utpu

t with

Cor

n (lb

/acr

e)

0

20

40

60

80

100

120

140

N Surplus (N Fertilizer Input – N Corn Output)

1990

1995

2000

2005

2010

2015N

Fer

t. In

put -

N G

rain

Out

put (

lb/a

cre)

0

20

40

60

80

100

120

140

N Loss versus Surplus

N Surplus (N Fert. - N Corn Output) (lb/acre)

20 40 60 80 100 120

Nitr

ate-

N L

oss

(lb/a

cre)

0

20

40

60

80

100

N Concentration versus Surplus

N Surplus (N Fert. - N Corn Output) (lb/acre)

20 40 60 80 100 120

Nitr

ate-

N C

once

ntra

tion

(lb/a

cre)

0

5

10

15

20

25

N Rate versus Load


0 50 100 150 200 250

Nitr

ate-

N L

oss

(lb/a

cre)

0

20

40

60

80

100

N-Rate versus Concentration


0 50 100 150 200 250 300

Nitr

ate-

N C

once

ntra

tion

(mg/

L)

0

5

10

15

20

25

30

N Surplus versus Load

N Surplus (lb/acre)

-50 0 50 100 150 200

Nitr

ate-

N L

oss

(lb/a

cre)

0

20

40

60

80

100

N Surplus versus Concentration

N Surplus (lb/acre)

-50 0 50 100 150

Nitr

ate-

N C

once

ntra

tion

(mg/

L)

0

5

10

15

20

25

30

Summary• Limited nitrate-N differences in drainage between fall

ammonia and spring ammonia application • Split application showing trends for reduced nitrate-N

concentrations in drainage compared to fall or spring pre-plant

• Even when no nitrogen is applied in a cornsoybean rotation the nitrate-N concentrations are about 7-10 mg/L for conditions studied

• Early fall manure application increased risk of nitrate-N loss and yield reduction for corn

• Use of a cover crop with early fall manure application reduces risk of nitrate-N loss

Discussion

[email protected]: @ISUAgWaterMgmt

Website: http://agwatermgmt.ae.iastate.edu/

mailto:[email protected]

Documents

Impacts of 4R Management on Drainage Water Quality · Matt Helmers – Director of the Iowa Nutrient Research Center, Professor in Dept. of Ag. And Biosystems Engineering and Dean’s