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
