matt ruark dept. soil sci. corn stover removal and soil fertility

Matt RuarkDept. Soil Sci.

CORN STOVER REMOVAL AND SOIL

FERTILITY

Is there a negative effect of stover removal in the short-term?

Yield reductionsLoss of SOC

Continual corn silage rotationsUse of corn silage as a feedstock for

biofuel

QUESTION

Review current research on effects of stover removal.

Show research from stover removal trials in Wisconsin.

What would a recommendation be for stover removal?

OUTLINE

STOVER REMOVAL AND CORN YIELD

IA: removal of stover, no effect on NT yield in 10 of 13 years (silty clay loam) (Morachum e t a l . , 1972 )

SC: 3 yr study, increase, decrease, no effect (sandy loam) ( Ka r l e n e t a l . , 1984 )

NE: removal reduced yield in 2 of 4 years (Wi l he lm e t a l . ,

1986 )

In Texas, removing sorghum stover decreased SOM over four years, but increased yields when no N was applied ( Pow e l l and Hons , 1991 )

In Ohio, removing 50% of biomass reduced corn yields by 26 bu/ac and removing 100% reduced corn yields by 50 bu/ac…but in only one of three sites. Ultisol, with 10% slope. (B l anco - Canqu i and La l , 2009 )

OHIO – 3 YRS OF STOVER REMOVALBlanco-Canqui and Lal, 2009

0 25 50 75 100

Ultisol, 1.9% SOC

Alfisol, 2.3% SOC

Alfisol, 2.5% SOC

Blanco-Canqui and Lal, 2007

Blanco-Canqui and Lal, 2007

0 25 50 75 100

% Stover Removal

LANCASTER, WI – 10 YR OF REMOVAL

Year Yield w/ removal

Yield w/ no removal

1981 153 1321982 92 851983 116 1081984 115 1201985 155 1661986 164 1771987 57 591988 128 1721989 155 1631990 155 156

Karlen et al., 1994

LANCASTER, WI – 10 YR OF REMOVAL

Karlen et al., 1994

Rozetta silt loam (Alfisol)

LANCASTER, WI – 10 YR OF REMOVAL

Stover treatment

Water content

(%)

Earthworms (#/m2)

Plant available water (%)

w/ removal 26.7 53 23.2

No removal 32.4 78 24.5

Karlen et al., 1994

90% stover removal (Mollisol):Reduced soil C by 12%Reduced soil N by 13%Reduced CEC by 7.3%Reduced N mineralization potential by

28%

ROSEMOUNT, MN – 19 YR OF REMOVAL Laird and Cheng, 2013

Originally conceived as a biofuel study to assess “safe” removal rates of stover

Funded by Wisconsin Fertilizer Research Council

Three locations:ArlingtonLancasterMarshfield

2009 establishment year2010-2012 study years

WISCONSIN RESEARCH

Evaluating a two-pass system (harvest & stover removal)

Three rates of stover removalNoneLow (~25%)High (~50%)

Six N rate to subsequent corn crop0, 50, 100, 150, 200, and 250 lb/ac of N as preplant urea

WISCONSIN RESEARCH

STOVER REMOVAL

YIELD EFFECTS

0 50 100 150 200 250 3000

20

40

60

80

100

120

140

160

180

f(x) = − 0.000470570831 x² + 0.097318321871 x + 144.3708425051R² = 0.372324266562818

f(x) = − 0.001167698762 x² + 0.405135500108 x + 123.1237558466R² = 0.98233543264851

f(x) = − 0.000542378984 x² + 0.213727463107 x + 128.5903669733R² = 0.58227577935108

2012 Arlington

No RemovalPolynomial (No Removal)Low Removal

N rate (lb/ac)

Yie

ld (

bu

/ac)

YIELD EFFECTS

0 50 100 150 200 250 3000

50

100

150

200

250

3002011 Lancaster

No RemovalLow RemovalHigh Removal

N rate (lb/ac)

Corn

Yie

ld (

bu

/ac)

YIELD EFFECTS

0 50 100 150 200 250 3000

20406080

100120140160

f(x) = 0.0000323438 x³ − 0.0134828 x² + 1.66948 x + 64.8268R² = 0.995208365273487

f(x) = 0.0000192968 x³ − 0.00925798 x² + 1.37633 x + 54.8325R² = 0.997424608945712

f(x) = 0.0000205183 x³ − 0.00842703 x² + 1.1264 x + 79.106R² = 0.944554602262403

2012 Lancaster

No RemovalPolynomial (No Removal)

N Rate (lb/ac)

Co

rn Y

ield

(b

u/a

c)

YIELD EFFECTS

0 50 100 150 200 250 3000

20

40

60

80

100

120

140

160

180

f(x) = 0.196301994045441 x + 114.524672987044R² = 0.910136284573808f(x) = 0.154955636491105 x + 111.586221224628R² = 0.940983275134757

f(x) = 0.196301994045441 x + 114.524672987044R² = 0.910136284573808

2011 Marshfield

No RemovalLinear (No Removal)Low Removal

N Rate (lb/ac)

Corn

Yie

ld (

bu

/ac)

Routine soil analysis (ph, OM, STP, STK) on all plots in 2009 and 2012

No change in pH over three yearsSlight decrease in SOM over three years

at all sites – and this was consistent across all stover removal rates and N rates

SOIL FERTILITY

STOVER ARL (EXH) LAN (HIGH) MAR (EXHIGH)

Reduction in STP (ppm)

NONE 11 5 16

LOW 11 3 19

HIGH 13 4 16

SOIL TEST P

ARL (High)No removal – reduction by 14 ppmLow removal – reduction by 21 ppmHigh removal – reduction by 54 ppm

LAN (Low STK) & MAR (Low STK) Increases of 10 to 14 ppmNo effect of stover removal

SOIL TEST K (2009 VS 2012)

STOVER REMOVAL AND P AND K VALUE Fixen (2007)

2-3 years of removal will have little effect Larger drawdowns of P and K on high testing soil

Would not recommend more than 5 years of removal

Other C inputs can offset negative impacts Manure and compost – C that can be immediately

assimilated Cover crops – C that needs to be decomposed, a

longer-term contribution to SOMCorn reside is not the only factor that

affects SOM

CAN WE DEVELOP A RECOMMENDATION?

CORN STOVER RETENTIONWilhelm et al., 2007

THANK YOU

THOUGHTS?QUESTIONS?CONCERNS?

1990 samples:CC: 12.2 to 14.0 SOC (g kg -1)Other: 15.3 to 16.3 SOC (g kg -1)

CC: 1.02 to 1.21 SON (g kg -1)Other: 1.27 to 1.33 SON (g kg -1)

LANCASTER EXPERIMENT