Using Biochar as a Soil Amendment for
Sustainable Agriculture
W. Zheng
B.K. Sharma
K. Rajagopalan
Biochar Symposium
Illinois Sustainable Technology Center (ISTC)
June 9, 2011
Using Biochar as a Soil Amendment for Sustainable Agriculture
Grant #: SA 09-37 (2009-2010)
Sustainable Agriculture Grant Program by
Illinois Department of Agriculture
Illinois Sustainable Technology
Center (ISTC)
Project Goal
The objective of this project was to examine the potential use of
biochar as a soil amendment in a typical corn field in Illinois as
part of a larger goal of promoting sustainable agricultural practice.
To achieve this goal, three tasks were undertaken in the project:
 Biochar production and characterization: Biochar production through a
low-temperature slow pyrolysis technique from a variety of waste biomass.
 Removal of nutrients by biochar: The sorption kinetics and mechanisms of
NH4+ and PO43- removal by biochar were investigated.
 Field trial to demonstrate the efficacy of biochar as a simple soil
amendment as measured by crop yields and lowered fertilizer use in Illinois,
which attempted to investigate if the use of biochar as a soil amendment
could reduce chemical fertilizer use while at the same time maintaining or
increasing crop yields.
Feedstock
The feedstocks used for biochar production in this study focused on
three kinds of waste biomass:
 Agricultural residues
corn cobs corn stover;
 Yard wastes
walnut shells and wood chips;
 By-products from bioenergy
defatted dried distiller grains (DDGs)
Pyrolysis
Syngas
H2, CO, CO2
Bio-oil
Waste Biomass
Pyrolysis
Pyrolysis is a most common thermochemical conversion
process where biomass is heated in the absence of oxygen to
yield a series of bioproducts: syngas; bio-oil; and biochar.
Biochar
Schematic Diagram for Biochar Production in a Slow Pyrolyzer
.
ISTC Sustainable Biochar
Effect of Selected Feedstocks and Pyrolysis Conditions on Yields of
Bioproducts
Biochar
Feedstock
ZW-1
Corn cob
32.2 %
45.6 %
Syngas
(%)
22.2%
ZW-2
Corn stover
39.0 %
42.8 %
18.2 %
ZW-3
Defatted DDG
45.8 %
40.3 %
14.9 %
ZW-4
Pine cone
38.0 %
44.4 %
17.6 %
America chestnut
shell
ZW-6-1*
Wood chip
42.2 %
45.6 %
12.2 %
35.0 %
42.0 %
23.0 %
ZW-6-2*
Wood chip
35.0 %
42.1 %
22.9 %
ZW-6-3*
Wood chip
35.1 %
42.1 %
22.8 %
ZW-5
Biochar (%) Bio-oil (%)
The yields of three bio-products produced from selected feedstocks under oxygen-limited condition
for 60 min at 400 oC.
*ZW-6-1, 2, and 3 refer to the feedstock pyrolyzed under 0, 2, and 5 L/min nitrogen flow.
Effect of Pyrolysis Temperature on the Yields of Bioproducts
60
Biochar
Product Yield (%)
50
Bio-oil
40
30
Syngas
20
10
250
300
350
400
450
500
o
Pyrolysis Temperature ( C)
550
Biochar Characterization on Physicochemical Properties
Feedstock
Pyrolysis
SSA
%C
%H
%N
%O
(O+N)/C
O/C
H/C
Temperature (m2/g)
%
%
Moisture
Ash
Corn cob
250 OC
1.86
61.16
4.96
0.82
27.82
0.353
0.341
0.973
1.32
3.92
Corn cob
300 OC
2.42
70.54
4.19
0.81
19.06
0.213
0.203
0.713
1.3
4.1
Corn cob
350 OC
3.36
72.92
3.79
0.79
16.86
0.183
0.173
0.624
1.29
4.35
Corn cob
400 OC
4.70
75.23
3.37
0.82
14.11
0.150
0.141
0.538
1.35
5.12
Corn cob
450 OC
7.79
77.84
2.95
0.86
11.45
0.120
0.110
0.455
1.35
5.55
Corn cob
500 OC
17.08 80.85
2.5
0.97
8.87
0.093
0.082
0.371
1.25
5.56
Corn cob
550 OC
30.57 82.62
2.25
0.84
7.43
0.076
0.067
0.327
1.28
5.58
Wood pellet
750 OC
105.3 81.99
1.14
0.52
3.04
0.033
0.028
0.167
4.56
8.75
Wood chip
450 OC
12.96 70.44
2.67
1.11
13.86
0.161
0.148
0.455
1.69
10.23
Defatted DDG
400 OC
1.98
64.43
3.76
7.44
10.14
0.217
0.118
0.700
1.45
12.78
Corn stover
400 OC
4.69
55.98
3.4
0.43
18.16
0.250
0.243
0.729
1.28
20.75
Pine cone
400 OC
17.92 73.88
3.21
1.33
15.31
0.171
0.155
0.521
1.32
4.95
91.1
0.9
0.28
5.71
0.050
0.047
0.119
1.12
0.89
Activated
carbon
988.4
Project Goal
The objective of this project was to examine the potential use of
biochar as a soil amendment in a typical corn field in Illinois as
part of a larger goal of promoting sustainable agricultural practice.
To achieve this goal, three tasks were undertaken in the project:
 Biochar production and characterization: Biochar production through a lowtemperature slow pyrolysis technique from a variety of waste biomass.
 Removal of nutrients by biochar: The sorption kinetics and mechanisms of
NH4+ and PO43- removal by biochar were investigated.
 Field trial to demonstrate the efficacy of biochar as a simple soil
amendment as measured by crop yields and lowered fertilizer use in Illinois,
which attempted to investigate if the use of biochar as a soil amendment could
reduce chemical fertilizer use while at the same time maintaining or increasing crop
yields.
Sorption Capacities of NH4+ and PO43- on Selected Biochars and a
Commercial Activated Carbon
Ammounium ion Cs (mmol/g)
0.3
PO43-
0.25
0.2
0.15
0.1
Phosphate ion Cs (mmol/g)
0.05
0.35
0
0.3
0.25
0.2
0.15
0.1
0.05
0
NH4+
1.0
PO43o
Biochar produced from wood chip at 750 C
o
Biochar produced from wood chip at 450 C
0.9
0.8
0.7
0
10
20
30
Time (hrs)
NH4+
40
50
Phosphate Ion Concentration (mmol/L)
Ammonium Ion Concentration (mmol/L)
Sorption Kinetics
1.0
0.9
o
Biochar produced from wood chip at 750 C
o
Biochar produced from wood chip at 450 C
0.8
0.7
0.6
0.5
0.4
0.3
0
10
20
30
Time (hrs)
40
50
Sorption Kinetics
To investigate the controlling mechanisms of sorption processes,
e.g., mass transfer and chemical reaction, the data obtained from
this study were analyzed using two kinetic equations: the pseudofirst order equation and the pseudo-second order equation:
where Qe and Qt are the amounts of nutrients sorbed (mmol/g) at equilibrium
and at time t (h), k1 and k2 are sorption rate constants of pseudo-first order and
pseudo-second order, respectively. The fit of these two models was checked by
the linear plot of log (Qe-Qt) versus t and t/Qt versus t, respectively, and by
comparison to the regression coefficients for each expression.
Sorption Kinetics
Pseudo-first order
NH4+
PO43-
k1
Qe (cal)
(h-1)
(mmol/g)
Biochar-750
0.115
7.87 x 10-3
Biochar-450
0.105
Biochar-750
Biochar-450
Pseudo-second order
R2
R2
k2
Qe (cal)
(mmol/g)-1h-1
(mmol/g)
0.959
68.6
2.44 x 10-2
0.999
1.41 x 10-2
0.992
28.9
3.14 x 10-2
0.995
0.119
6.05 x 10-2
0.984
1.23
8.61 x 10-2
0.932
0.097
5.79 x 10-2
0.990
0.013
4.81 x 10-1
0.006
Pseudo-first order and pseudo-second order sorption rate constants of NH4+ and
PO43- on two selected biochars
Sorption Isotherms of NH4+ and PO43- on Selected Biochars
NH4
+
PO4
0.4
3-
NH4
0.20
Cs (mmol/g)
0.3
+
o
Biochar produced from wood pellet at 750 C
o
Biochar produced from wood chip at 450 C
0.1
0.15
Cs (mmol/g)
0.2
0.0
0
0.10
5
10
15
20
Ce (mmol/L)
o
Biochar produced from wood pellet at 750 C
o
Biochar produced from wood chip at 450 C
0.05
PO43-
0.00
0
5
10
15
20
Ce (mmol/L)
25
30
25
30
Sorption Isotherm
Freundlich isotherm
Langmuir isotherm
log Cs = log Kf + 1/n log Ce
Ce/Qe = 1/(bQ0) + Ce/Q0
Kf
1/n
R2
(mmol/g) (mmo/L)-n
NH4+
PO43-
Q0
b
(mmol/g)
(L/mmol)
R2
Biochar-750
2.56 x 10-2
0.650 0.971
0.246
0.108
0.933
Biochar-450
4.12 x 10-2
0.516 0.981
0.234
0.190
0.974
Biochar-750
5.74 x 10-2
0.795 0.895
0.576
0.140
0.835
Biochar-450
3.60 x 10-2
0.933 0.873
0.787
0.047
0.270
Removal Mechanisms of Phosphate & Ammonium by Biochar
Precipitation process
Ca2+ + PO43- +.xH20 → Ca3(PO4)2.xH20
Biochar no washing
mg/L
mg/L
< 0.6
< 0.6
Potassium*
7.7
15
Calcium*
2.8
3.8
Beryllium
< 0.002
< 0.002
0.089
0.094
Magnesium
1.5
2.3
Aluminum
0.075
0.084
2.0
1.0
Titanium
0.0027
0.0022
Vanadium
< 0.001
< 0.001
Chromium
0.0032
0.0033
Manganese
0.0077
0.0055
< 0.1
0.11
-21.9±3.8
-22.3±6.9
Analyte Units
Sodium*
50
Phosphate removal (%)
Biochar after DI H2O
washing
40
30
Boron
20
10
Silicon
0
Biochar no washing
Biochar with
DI H2O washing
Surface sorption
Biochar with negatively
charged surface
Iron*
Zeta potential (ζ)
Sorption Mechanism of Phosphate by Biochar
Ca2+ + PO43- +.xH20 → Ca3(PO4)2.xH20
Ca3(PO4)2.xH20
XAD patterns of before and after PO43- adsorption by biochar
Project Goal
The objective of this project was to examine the potential use of
biochar as a soil amendment in a typical corn field in Illinois as
part of a larger goal of promoting sustainable agricultural practice.
To achieve this goal, three tasks were undertaken in the project:
 Biochar production and characterization: Biochar production through a lowtemperature slow pyrolysis technique from a variety of waste biomass.
 Removal of nutrients by biochar: The sorption kinetics and mechanisms of
NH4+ and PO43- removal by biochar were investigated.
 Field trial to demonstrate the efficacy of biochar as a simple soil
amendment as measured by crop yields and lowered fertilizer use in Illinois,
which attempted to investigate if the use of biochar as a soil amendment could
reduce the application rates of chemical fertilizer while at the same time
maintaining or increasing crop yields.
2010 Biochar Field Experiment Design
90 Feet and 36 rows
60
Feet
No Fertilizer
Half Fertilizer
Full Fertilizer
10 feet x 0.66 feet used for biochar treatments
No Fertilizer
Half Fertilizer
Full Fertilizer
Biochar Application in a Corn Field
Biochar Application in Corn Field
Standard corn
growing practices
ISTC Biochar Website
http://www.istc.illinois.edu/research/biochar.cfm
Biochar Application in Corn Field
Yeilds of Corn Crop (bushel/acre)
280
240
No Fertilizer
50% Fertilizer
100% Fertilizer
200
160
120
80
40
0
Control
Biochar-B
Biochar-A
0
50 %
100 %
No Biochar
139.3 a
174.3 a
173.0 a
Biochar-A
164.6 b
213.7 b
239.8 b
Biochar-B
170.9 b
194.2 b
201.3 a
Nitrogen Fertilizer
Selected Soil Properties Before and After Experiments
Treatments
Soil
Organic
Matter
(%)
Neutral Ammonium Acetate
(exchangeable)
P1
mg/kg
P1
mg/kg
K
mg/kg
Mg
mg/kg
Ca
mg/kg
pH
Cation
Exchange
Capacity
(CEC)
meq/100g
Phosphorus
Nitrate-N
mg/kg
Before experiment
No fertilizer and no biochar
No fertilizer with biochar-A
No fertilizer with biochar-B
3.2
3.6
4.1
15
19
20
22
23
28
206
326
218
345
274
349
1953
1808
2046
5.8
5.7
5.7
16.3
15.4
17.3
19
39
35
50% fertilizer and no biochar
4.2
19
32
180
438
2340
5.6
20.7
32
50% fertilizer with biochar-A
4.7
27
42
358
406
2474
5.6
19.0
33
50% fertilizer with biochar-B
4.0
21
31
251
362
1986
5.2
20.8
67
100% fertilizer and no biochar
4.6
12
17
172
527
2617
6.0
21.1
34
100%fertilizer with biochar-A
4.6
22
43
195
449
2422
5.9
19.7
75
100% fertilizer with biochar-B
After experiment (at harvest)
No fertilizer and no biochar
No fertilizer with biochar-A
No fertilizer with biochar-B
3.3
15
24
149
345
1878
5.4
17.6
74
3.9
5.0
4.5
20
33
19
30
46
31
198
259
166
310
318
329
1906
2105
1915
5.4
6.1
5.8
15.2
16.1
20.1
21
12
21
50% fertilizer and no biochar
4.5
22
38
176
366
2234
5.5
18.3
32
50% fertilizer with biochar-A
5.5
40
74
342
313
2298
6.2
19.0
29
50% fertilizer with biochar-B
4.8
29
47
179
324
2077
6.1
21.3
25
100% fertilizer and no biochar
4.2
14
21
175
456
2398
5.8
17.7
58
100%fertilizer with biochar-A
5.1
35
60
239
403
2308
6.5
22.6
13
100% fertilizer with biochar-B
4.9
27
39
221
376
2247
5.9
20.9
56
Colleagues
 Dr. Sharma, B.K.
 John Scott
 Dr. Li, X.
 Christie Teausant
 Nancy Holm
 Brent Panno
 Dr. Rajagopanlan, K.
 Dr. Kulkarni, M.
 Dr. Marlin, J.
 Monte Wilcoxon
 Joe Pickowitz
 Ed Zaborski
Acknowledgments
This study is being supported by Illinois Department of Agriculture’s Sustainable
Agriculture Grant Program
Questions
Stay on the Stage