figure 8. potential sink or source for atmospheric co 2 -c
DESCRIPTION
Figure 1. Residue removal effects on corn yields as affected by N rate in 2009 and 2010 for poorly and well-drained soils. Asterisk indicates significant difference between residue removal within each N rate at p=0.05. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Figure 8. Potential sink or source for Atmospheric CO 2 -C](https://reader036.vdocuments.mx/reader036/viewer/2022062519/56815162550346895dbf8b28/html5/thumbnails/1.jpg)
South West, Iowawell draining soil
SIde-dressed UAN (lbs N ac-1)
0 50 100 150 200 250
Cor
n Y
ield
(bu
ac-1
)
0
50
100
150
200
250
SIde-dressed UAN (lbs N ac-1)
0 50 100 150 200 250
2010
North Central, Iowapoorly draining soil
Cor
n Y
ield
(bu
ac-1
)
0
50
100
150
200
250
300
0 % removal50 % removal100 % removal
2009 2009
2010
*
*
*
**
*
*
**
**
Figure 1. Residue removal effects on corn yields as affected by N rate in 2009 and 2010 for poorly and well-drained soils. Asterisk indicates significant difference between residue removal within each N rate at p=0.05.
![Page 2: Figure 8. Potential sink or source for Atmospheric CO 2 -C](https://reader036.vdocuments.mx/reader036/viewer/2022062519/56815162550346895dbf8b28/html5/thumbnails/2.jpg)
North Central, Iowapoorly draining soil
Residue Removal (%)
0 50 100
Co
rn Y
ield
(b
u a
c-1)
0
20
40
60
80
100
120
140
160Chisel plowNo-till
South West, Iowawell draining soil
Residue Removal (%)
0 50 100
bab
a
c
b b
c
ba
d
b b
Figure 2. Residue removal effects on corn yields as affected by tillage in 2010 for poorly and well-drained soils. Different letters indicate significant difference between residue removal and tillage at p=0.05.
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North Central, Iowapoorly draining soil
Corn Residue Removal (%)
0 50 100
Soi
l Org
anic
Car
bon
(%)
0
1
2
3
4
5
6Chisel plowNo-till
Baseline = 4.46
South West, Iowawell draining soil
Corn Residue Removal (%)
0 5 10
Baseline= 2.39
aa a
aa
aa a a a
a
a
Figure 3. Total soil carbon as affected by two years of residue removal for poorly and well-drained soils. Different letters indicate significant difference between residue removal at p=0.05.
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Corn Residue Removal (%)
0 20 40 60 80 100
Corn Residue Removal (%)
0 20 40 60 80 100
Corn Residue Removal (%)
0 20 40 60 80 100
SW
Iow
a, w
ell d
rain
ing
soi
lN
et S
OC
Seq
uest
ratio
n (t
on C
ac-1
)
-2.0
-1.5
-1.0
-0.5
0.0
0.5
0 lbs N ac-1
NC
Iow
a, p
oorly
dra
inin
g s
oil
Net
SO
C S
eque
stra
tion
(ton
C a
c-1)
-2.0
-1.5
-1.0
-0.5
0.0
0.5Chisel plowNo-till
150 lbs N ac-1 250 lbs N ac-1
y = -0.6228 - 0.0036x, R2 = 0.72, CPy = -0.5281 - 0.0038x, R2 = 0.97, NT
y = -0.3059 - 0.0090x, R2 = 0.90, CPy = -2049 - 0.0083x, R2 = 0.98, NT
y = -0.1649 - 0.0086x, R2 = 0.91, CP
y = 0.1377 - 0.0092x, R2 = 0.82, NT
y = -0.8993 - 0.0006x, R2 = 0.61, CP
y = -0.6428 - 0.0016x, R2 = 0.54, NTy = -0.5230 - 0.0036x, R2 = 0.54, CP
y = -0.2915 - 0.0080x, R2 = 0.90, NT
y = -0.1397 - 0.0089x, R2 = 0.85, CPy = 0.0584 - 0.0068x, R2 = 0.92, NT
Figure 4. Potential changes to net soil organic carbon from carbon input from above- and below-ground biomass minus losses from microbial respiration to a depth of 15 cm. Carbon budget was conducted in 2010 in a well-drained soil and poorly-drained soil under different tillage and N fertilization regimes.
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North Central, Iowapoorly draining soil
Residue Removal (%)
0 50 100
Bu
lk D
en
sity
(g
cm
-3)
1.0
1.1
1.2
1.3
1.4
1.5
1.6Chisel plowNo-till
South West, Iowawell draining soil
Residue Removal (%)
0 50 100
bb
a
b b
a
a
bb b
a a
Baseline: 1.25Baseline: 1.28
Figure 5. Soil bulk density as affected by two years of residue removal and tillage systems for poorly and well-drained soils. Different letters indicate significant difference between residue removal and tillage at p=0.05.
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North Central, Iowapoorly draining soil
Residue Removal (%)
0 50 100
Ag
gre
ga
te M
ea
n W
eig
ht D
iam
ete
r
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8Chisel plowNo-till
North Central, Iowapoorly draining soil
SIde-dressed UAN (kg N ha-1)
0 170 280
bbc
c
a
c c b
aa
Figure 6. Aggregate mean weight diameter as affected by two years of residue removal, tillage and nitrogen rate systems for a poorly-drained soil site. Different letters indicate significant difference between residue removal, tillage and nitrogen rate at p=0.05.
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North Central, Iowapoorly draining soil
Residue Removal (%)
0 50 100
Ste
ad
y In
filtr
atio
n R
ate
(cm
min
-1)
0.0
0.1
0.2
0.3
Chisel plowNo-till
South West, Iowawell draining soil
Residue Removal (%)
0 50 100
aa a a a a
a
ab
c
a
aba
Figure 7. Steady water infiltration rates as affected by residue removal and tillage for poorly and well-drained soil sites. Different letters indicate significant difference between residue removal and tillage at p=0.05.
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0% Removal
Side-dressed UAN (N lbs ac-1)
0 150 250
Net
Gai
n o
r L
oss
of
CO
2 (l
bs
CO
2-C
ac-1
)
-1
0
1
2
3
4
5Chisel PlowNo-till
50% Removal
Side-dressed UAN (N lbs ac-1)
0 150 250
100% Removal
Side-dressed UAN (N lbs ac-1)
0 150 250
aa
a
b
c c
abab abab
c
c
b
abb
bc
cc
Figure 8. Potential sink or source for Atmospheric CO2-C .1. Include above ground biomass, grain, and root biomass for ANPP2. (ANPP + BNPP) – Rh 3. Positive values indicate a sink for atmospheric CO2
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2010
Day of Year
50 100 150 200 250 300
2009
Day of Year
50 100 150 200 250 300
So
il S
urf
ace
CO
2 E
fflu
x (l
bs
ac-1
day
-1)
0
100
200
300
Chisel Plow, 0 % removedChisel Plow, 50 % removedChisel Plow, 100 % removedNo-tillage, 0 % removedNo-tillage, 50 % removedNo-tillage, 100 % removed
Figure 9. Seasonal CO2 emissions under different residue removal and tillage management in 2009 and 2010 for the poorly drained soil site in Ames.
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2009
Day of Year
100 150 200 250
So
il S
urf
ace
N2O
Eff
lux
(g N
ha-1
day
-1)
0
50
100
150
200
250Chisel PlowNo-tillage
2010
Day of Year
100 150 200 250
So
il Mo
isture (cm
3 cm-3 vo
l %)
0
5
10
15
20
25
30
35
40
45
50
Chisel Plow moistureNo-till moisture
*
***
*
*
*
*
Figure 10. Seasonal N2O emissions under different tillage management in 2009 and 2010 for the poorly drained soil site in Ames.
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2009 2010
Ave
rag
e S
oil
Su
rfa
ce
N2O
Eff
lux
(g N
ha-1
da
y-1)
0
10
20
30
40
50
600 % Residue Removed50 % Residue Removed100 % Residue Removed
a
bb
a
a
a
Figure 11. Mean annual N2O emissions under different corn residue removal management in 2009 and 2010 for the poorly drained soil site in Ames.
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Table 1. Effect of N fertilizer Rate on Corn Biomass N and C Content at Plant Maturity Across Sites, 2009-2010 (John Sawyer and Jose Pantoja).
N Rate Veg. Cob Grain Total Veg. Cob Grain Total
lb N/acre - - - - - - - - - -lb N/acre - - - - - - - - - - - - - - - - - - - - - -lb C/acre - - - - - - - - - - - - - -
0 28 (43%) 3 (4.6%) 34 (52%) 651,770 (50%) 230 (5.5%) 1,555 (44%) 3,550
150 59 (38%) 6 (4.0%) 89 (58%) 1543,140 (43%) 510 (7%) 3,670 (50%) 7,320
250 73 (40%) 7 (3.8%) 103 (56%) 183 3,375 (42%) 555 (7%) 4,080 (51%) 8,010
Only the main effect of N rate was statistically significant for N and C (p<0.001).
Veg., vegetative material.