Communications in Soil Science and Plant Analysis
ISSN: 0010-3624 (Print) 1532-2416 (Online) Journal homepage: https://www.tandfonline.com/loi/lcss20
Kinetics of Carbon Mineralization and
Sequestration of Sole and/or Co-amended Biochar
and Cattle Manure in a Sandy Soil
Daniel E. Dodor, Yahaya J. Amanor, Abena Asamoah-Bediako, Dilys S.
MacCarthy & Delali B.K. Dovie
To cite this article: Daniel E. Dodor, Yahaya J. Amanor, Abena Asamoah-Bediako, Dilys S.
MacCarthy & Delali B.K. Dovie (2019) Kinetics of Carbon Mineralization and Sequestration of Sole
and/or Co-amended Biochar and Cattle Manure in a Sandy Soil, Communications in Soil Science
and Plant Analysis, 50:20, 2593-2609, DOI: 10.1080/00103624.2019.1671443
To link to this article:  https://doi.org/10.1080/00103624.2019.1671443
Published online: 03 Oct 2019.
Submit your article to this journal 
Article views: 72
View related articles 
View Crossmark data
Full Terms & Conditions of access and use can be found at
https://www.tandfonline.com/action/journalInformation?journalCode=lcss20
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS
2019, VOL. 50, NO. 20, 2593–2609
https://doi.org/10.1080/00103624.2019.1671443
Kinetics of Carbon Mineralization and Sequestration of Sole and/or
Co-amended Biochar and Cattle Manure in a Sandy Soil
Daniel E. Dodor a, Yahaya J. Amanor a,b*, Abena Asamoah-Bediako a,
Dilys S. MacCarthy c, and Delali B.K. Dovie d
aDepartment of Soil Science, University of Ghana, Legon, Ghana; bInstitute of Agriculture and Environment, Massey
University, Palmerston North, New Zealand; cDepartment of Soil Science, Soil and Irrigation Research Centre, Kpong,
University of Ghana, Legon, Ghana; dRegional Institute for Population Studies, University of Ghana, Legon, Ghana
ABSTRACT ARTICLE HISTORY
The interactive effect of biochar, cattle manure and nitrogen (N) fertilizer on Received 28 March 2019
the dynamics of carbon (C) mineralization and stabilization was investigated Accepted 4 September 2019
in a sandy soil amended with three sole biochar (0, 20 or 40 t ha−1) or
manure (0, 13 or 26 t ha−1) and four combined biochar-manure levels (20 or KEYWORDS
−1 Biochar; C mineralization;40 t ha biochar plus 13 or 26 t ha−1 manure) with or without N fertilizer (0
−1 C sequestration; cattleor 90 kg ha ) and CO2-C evolution measured over 54-d incubation period. manure; kinetic models;
Biochar application, solely or combined with manure resulted in lower sandy soils
applied C mineralized (ACM), indicating C sequestration in the soils.
Negative attributable effect (AE) of co-application of biochar and manure
on C mineralization was observed relative to the sole treatments. Both ACM
and AE were negatively correlated with C/N ratio and mineral N content of
the soil-mixtures (r ≥ – 0.573; p ≤ 0.01), indicating microbial N limitation.
The double first-order exponential model described CO2-C efflux very well
and indicated that ≥94% of C applied was apportioned to stable C pools
with slower mineralization rate constant and longer half-life. Cumulative
C mineralized and modeled C pools were positively correlated with each
other (r ≥ 0.853; p ≤ 0.001) and with readily oxidizable C of soil-amendment
mixtures (r ≥ 0.861; p ≤ 0.001). The results suggested that co-application of
biochar and manure can promote initial rapid mineralization to release
plant nutrients but sequester larger amounts of applied C in refractive
C pool, resulting in larger C sequestration in sandy soils.
Introduction
The development of soil management systems to mitigate climate change through stabilization of
soil organic matter (SOM) and sequestration of carbon (C) is an important and critical component
of soil fertility management for crop production in sandy soils (Lu et al. 2014; Novak et al. 2010; Rittl
et al. 2015), especially in the semi-arid and sub-humid regions of the tropics. To replenish and/or
maintain organic matter (OM) content in these soils, manure is extensively applied and incorporated
into the surface 0–20 cm layer of the soil every growing season. However, due to its low stability,
coupled with the high temperature and humid soil conditions peculiar to such areas, the manure is
mineralized very fast. This results in slow buildup of SOM and contributes to significant increase in
the concentration of CO2 in the atmosphere, a major concern for global warming. In addition, the
conventional inversion tillage practice in sandy soils invariably accelerates decomposition of added
organic residues (Bauer et al. 2006), reducing not only its values as a soil amendment but also its
capacity as a C sequestration strategy.
CONTACT Daniel E. Dodor dedodor@ug.edu.gh Department of Soil Science, University of Ghana, Legon, Ghana
*Present address: Institute of Agriculture and Environment, Massey University, Palmerston North, New Zealand.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lcss.
© 2019 Taylor & Francis Group, LLC
2594 D. E. DODOR ET AL.
Biochar is a C-rich material produced from thermal degradation of organic feedstocks under limited oxygen
condition (Lehmann and Joseph 2009). Due to its recalcitrant nature, biochar has been suggested as an
alternative C management strategy to sequester C and improve the fertility status of impoverished soils
(Smider and Singh 2014). Furthermore, biochar contains high proportion of stable forms of aromatic rings,
oxidized and easily degradable aliphatic C, and hence its application can ameliorate the rapid degradation of
SOM in tropical soils (Sohi et al. 2010). The complex physico-chemical properties of biochar such as texture,
particle size, surface area, and water holding capacity are determined by the feedstock it is made from, the
temperature, heating rate and holding time during pyrolysis. The extent of aromatic structure formation in
biochar increases with the pyrolysis temperature (Brewer et al. 2009), with low pyrolysis temperature yielding
acidic biochar, while high pyrolysis temperature produces alkaline biochar (Zhang et al. 2013), higher C/N ratio
(Novak, Cantrell, and Watts. 2013; Ronsse et al. 2013) and a lesser concentration of dissolved organic C (Budai
et al. 2014; Rajapaksha et al. 2014). Higher pyrolysis temperatures also increase the surface area and sorption
capacity of biochar (Tang et al. 2013), and micropore volume (Angin and Şensӧz 2014).
Application of biochar has been shown to influence soil physical properties such as porosity, bulk density
and improved soil structure, aggregation and water retention (Glaser, Lehmann, and Zech 2002; Laird
et al. 2010; Sohi et al. 2010). In addition, amendment of soils with biochar has been shown to increase soil
quality, nutrient cycling, C sequestration, and increased pH, potassium and available phosphorus in soils
(Laird et al. 2010; Van de Voorde et al. 2014). Owing to its low content ofmajor plant nutrients such asN,
however, it is recommended to co-apply biochar with other organic amendments to improve its plant
nutritive value and hence crop yields (Fernández et al. 2014). Indeed, co-application of biochar and other
organic amendments have been reported to result in synergistic positive effect on soil organic carbon
(SOC) content, nutrient levels in soils and plant uptake, leading to improved plant growth and yield
(Agegnehu et al. 2015). Combined application of biochar and other organic amendments such as green
and animal manures have also been shown to increase C mineralization compared to individual
applications (Luo et al. 2011; Troy et al. 2013). However, these findings are not conclusive as other
researchers have reported decreased mineralization of SOC following the combined application of
biochar and other organic amendments (Rogovska et al. 2011).
When a mixture of organic materials of very different C pools are co-applied to the soil,
a complex set of interactions can affect the kinetics of the C mineralization process, which can
also change with the rate of application of these amendments. For example, a study in our laboratory
indicated that sole application of biochar and manure resulted in up to 125% positive priming of
SOC in a sandy soil (Dodor et al. 2018). However, co-application of the two amendments de-
accelerated the rate of decomposition and stabilized C in the soils, subsequently leading up to 35%
negative priming effect, albeit with a short-term mineral N limitation (Dodor et al. 2018). Owing to
the fact that the effect of co-applied biochar and manure on C mineralization and stabilization
depends on the interaction with soil properties, local edaphic conditions and cropping systems, it is
of interest to conduct in-depth studies to elucidate the kinetics of C mineralization and stability of
organic amendments as influenced by co-applied biochar, with or without N fertilizer application
and the subsequent impact on plant nutrient release in this soil. Although this knowledge is essential
for the proper management of sandy soils, it is still poorly understood.
The determination of quantitative information on the decomposition rates of co-applied biochar-
manure mixtures in soils through modeling can provide important information about the processes
influencing C mineralization and stability in soils. A variety of models have been used to determine
the mineralization rates and kinetic parameters of organic amendments added to soils (Ajwa and
Tabatabai 1994; Zimmerman, Gao, and Ahn 2011). Most of the C mineralization models involve the
use of either the single or double-exponential first-order equations, depending on the heterogeneity
of the organic material (Ajwa and Tabatabai 1994; Qayyum et al. 2012; Zhao, Coles, and Wu 2015;
Zimmerman, Gao, and Ahn 2011).
In this study, we hypothesized that co-application of biochar and manure will change the C pools
and induce slower C mineralization rates, resulting in increased C sequestration, but sole application
of the amendments will decrease C sequestration in the soil. In addition, the implication of these
interactions is likely to change with the application rates of the two amendments. Therefore, the
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2595
objectives of the present study were to (i) investigate the influence of sole and/or co-applied rice
husk biochar and cattle manure and their interaction with N fertilizer on C mineralization in a dry
equatorial coastal savanna sandy soil, and (ii) determine the rate and kinetic parameters of the
C mineralization process.
Materials and methods
Biochar, manure and soil
The biochar used was produced from rice husk (Oryza sativa) by a slow pyrolysis under limited
oxygen conditions at target temperature of 500°C. The biochar was held in the furnace for 1.5 h once
the target temperature was reached. After pyrolysis, the biochar samples were crushed and passed
through 2-mm sieve to ensure homogeneous size fractions but were not exposed to any aging
treatment before use. The cattle manure was sampled from small heaps on a farmer’s field at Anloga,
a semi-arid coastal savanna region located in the Keta District of the Volta Region in southeast
Ghana (Longitude: 0° 53ʹ50.21”E, Latitude: 5° 47ʹ41.03” N). The manure did not undergo any
stabilization treatment, except the natural biodegradation process during their storage in the heap.
The manure was air-dried and crushed to pass through 2-mm sieve. Surface soil (0–20 cm depth)
samples were collected from uncultivated fields in Anloga (Longitude: 0° 53ʹ50.21”E, Latitude: 5°
47ʹ41.03” N). After air-drying, the soil samples were passed through a 2-mm sieve and thoroughly
homogenized. The mineral N fertilizer used was ammonium sulfate (NH4)2SO4. The N fertilizer
application rates were adapted to the common field application rates used by farmers in the region.
The analytical procedure and physicochemical properties of the biochar, manure and soil have been
presented by Dodor et al. (2018).
Experimental design
Three factors, namely biochar (0, 20 or 40 t ha−1), manure (0, 13 or 26 t ha−1) and N fertilizer
addition (0 or 90 kg ha−1) were tested in a full factorial experimental design. In all, there were 18
treatments which were factorially combined with three replications to give a total of 54 experi-
mental units. The treatments were denoted with B (biochar), M (manure) and N (N fertilizer)
followed by their respective sole and/or combined biochar-manure application rates. The amend-
ments were thoroughly mixed with 500 g of soil samples and placed in 1.5 L wide mouth jars.
Details of the procedure followed for the incubation experiment has been reported by Dodor et al.
(2018).
The net CO2-C efflux from biochar and/or manure amended soils were calculated using the
following equation:
Net CO2 
 C ¼ CO2 
 CðtreatmentÞ 
 CO2 
 CðcontrolÞ (1)
where CO2-C (treatment) is the cumulative CO2-C efflux from amended soils, and CO2-C (control) is the
CO2-C evolved from soils without amendment. The amount of applied C mineralized (ACM; mg
CO2-C [g C applied]
−1) was calculated to evaluate the effect of adding different amounts of C to the
soil in each treatment using the following equation:
ð Þ ¼ ½Net CO2 
 CðtreatmentACM %  100 (2)
Orgnic C added
To evaluate the interactive influence of biochar, manure and N fertilizer on C mineralization, the net
CO2-C efflux from combined biochar and manure treatments were compared with the sum of the
net CO2-C evolved from the corresponding sole biochar and manure amended soils. The attributable
effect (AE%) of co-application of biochar and manure on C mineralization, which is the percent
2596 D. E. DODOR ET AL.
increase or decrease in net CO2-C evolution in the co-amended relative to the sole treatments, with
or without N fertilizer, was calculated using the following equation:
ð Þ ¼ ½Measured net CO2 
 C 
 Expected net CO2 
 CAE %  100 (3)
Measured net CO2 
 C
where “measured” is the net CO2-C efflux from combined biochar and manure amended soils and
“expected” is the sum of the net CO2-C evolved from the corresponding sole biochar and manure
treatments. Positive AE value indicates increased C mineralization, and negative AE indicates the
reverse.
The cumulative CO2-C efflux data were fitted to the double-exponential first-order kinetic model
representing a biphasic pattern of mineralization of the added C, using the following equation
(Molina, Clapp, and Larson 1980):
¼ 
  
 C C klt kstm l 1
 e þ Cs 1
 e (4)
where Cm is the amount of C mineralized at time t (day), Cl is the size of the labile mineralizable
C pool, and Cs is the size of the stable mineralizable C pool, kl and ks are the corresponding
mineralization rate constants (day−1) for each C pool. The rate constants of the Cl and Cs pools were
used to calculate their respective half-lives (t½) using the following equation:
¼ lnð2Þt1 (5)=2 k
At the end of the incubation period, readily oxidizable carbon (ROC) content was determined by
shaking air-dried soil samples with 333 mM KMnO4 for 1 h, followed by centrifugation and
measuring of the absorbance of the filtrate at 565 nm (Blair, Lefroy, and Lisle 1995). Mineral
N content of the soils after incubation were extracted with 2 M KCl and the amount of NH4 and
NO3-N were determined by steam distillation (Mulvaney 1996).
Statistical analysis
The cumulative C mineralized (CCM), ACM and kinetic parameters were subjected to a three-way
analysis of variance (ANOVA) to identify the primary factors influencing C mineralization. Tukey’s
LSD test was used to compare multiple means of variables when treatment effects were found at the
5% level of significance. Spearman correlation analysis was used to evaluate the relationship among
CCM, ACM, AE, ROC, and C/N ratio of the soil mixtures. All statistical analysis were done using
GenStat version 12 (VSN International); kinetic modeling of C mineralization was done using
SigmaPlot 11.0, and figures were drawn using GraphPad Prims 7 for windows.
Results
Carbon mineralization
The temporal pattern of C mineralization rates in the various treatments showed that maximum CO2-C
release rates were observed in all amended soils during the first 7-d of incubation followed by a slower
rate throughout the remaining period (Figure 1). The C mineralization rates during the initial first
7-d of the incubation ranged from 16.3 mg kg−1 day−1 in the control to 41.4 mg kg−1 day−1 in the
B40M26F90 treatment (Table 1), with the amount of C mineralized during this period (7-d) constitut-
ing 33 – 47% of the total C mineralized during the entire 56-d incubation period (Table 1). The initial
C mineralization (ICM) rates were significantly (P < .05) higher in soils amended with manure, solely or
combined with biochar compared with sole biochar treated or control soils (Table 1). The ICM values
increased with increasing manure application rates in the sole manure and combined biochar-manure
treated soils (Table 1). Except for the control and the lower sole biochar (B20M0) treatments,
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2597
Figure 1. Carbon mineralization rates in soils amended with (a) sole biochar (B) or manure (M) without N fertilizer (F), (b) sole
B or M with F, (c) combined B-M without F, and (d) combined B-M with F and incubated for 56 days (n = 3). B0, B20 and B40 are
B rates at 0, 20 and 40 t ha-1, respectively. M0, M13 and M26 are M rates at 0, 13 and 26 t ha-1, respectively. F0 and F90 are F rates
at 0 and 90 kg kg-1 soil, respectively.
Table 1. Cumulative CO2-C flux values from soils amended with sole and/or combined manure and biochar on days 7 and 56 of
incubation.
Cumulative CO2-C efflux (mg CO2-C kg
−1)
Incubation period (days)
Treamenta N treatment 7 56 Initial C mineralization rate (mg CO −1 −12-C kg day )
B0M0 0 114 297 16.3
90 142 287 20.2
B0M13 0 227 568 32.4
90 226 555 32.3
B0M26 0 259 666 36.9
90 268 716 38.3
B20M0 0 163 419 23.4
90 191 487 27.3
B40M0 0 208 522 29.7
90 209 449 29.9
B20M13 0 236 670 33.7
90 236 504 33.7
B20M26 0 272 771 38.8
90 280 851 40.0
B40M13 0 257 620 36.7
90 254 690 36.4
B40M26 0 283 826 40.4
90 290 754 41.4
LSD 11 80
aB0, B20 and B40 are biochar rates at 0, 20 and 40 t ha−1, respectively. M0, M13 and M26 are manure rates at 0, 13 and 26 t ha−1,
respectively.
2598 D. E. DODOR ET AL.
N application did not influence ICM rates insole and/or combined biochar and manure amended soils
(Table 1). The ICM rates were positively and significantly correlated with initial C applied (r = 0.633; P
< .01) and C/N ratio of the soil-mixtures (r = 0.431; P < .05).
The cumulative amounts of C mineralized as CO2 showed a curvilinear relationship with two
major inflections in the exponential curves during the 56-d incubation period (data not shown). Sole
application of biochar or manure, with or without N fertilizer, resulted in significant (P < .05)
increase in the total amount of CO2-C release relative to the unamended control soil, with total CO2
-C efflux from the higher manure application rate being significantly (P < .05) higher than that from
the biochar treated soils (Table 1). The total amount of CO2-C evolved increased with increasing
manure application rate (Table 1). Generally, the total amount of CO2-C released from the amended
soils, with or without N fertilizer, were similar (Table 1).
Three-way ANOVA indicated that CCM was significantly (P < .001) influenced by biochar and
manure applications, as well as their interactions (Table 2). Application of N fertilizer did not
influence CCM, however, there was a significant interaction among the three factors. The CCM was
positively and significantly correlated with the amount of C applied (r = 0.584; P < .01) and manure
application rate at fixed biochar rates (r = 0.891; P < .001); however, the correlation with biochar
application rate at fixed manure rate was not significant (r = 0.324; P= .1898). As expected, ICM and
CCM were positively and significantly correlated (r = 0.946; P < .001).
Applied c mineralized (ACM) and attributable effect (AE)
The ACM in sole manure amended soils ranged from 18.6% to 27.4%, with values decreasing with
increasing manure application rates (Figure 2). Sole application of biochar significantly (P < .05)
decreased ACM values to 2.8–5.9%, with values at the two application rates being statistically (P >
.05) similar (Figure 2). The ACM values in the sole biochar treated soils are significantly (P < .05)
lower than those in the manure amended soils, with or without N fertilizer application (Figure 2).
The ACM values of soils treated with combined biochar and manure ranged from 4.7% to 6.8%,
with lower values recorded at higher biochar at fixed manure application rates (Figure 2). The
ACM values obtained in the combined biochar-manure treated soils were similar (P > .05) to
those observed in the sole biochar treatments. Application of N fertilizer did not affect ACM
values in both sole and combined biochar and manure amended soils (Figure 2).
The three-way ANOVA indicated that biochar and manure application significantly (P < .001)
influenced ACM, and so were their interactive effects (Table 2). Application of N fertilizer did not
influence ACM values, however, there was a significant interaction among the three factors. The
ACM values were negatively and significantly correlated with biochar application rates (r = – 0.804;
P= .005) but positively and significantly correlated with manure application rate (r = 0.640; P= .01).
The ACM values were negatively and significantly correlated with the initial C applied (r = – 0.665; P
< .003) and C/N ratio of the soil-mixtures (Figure 3; r = – 0.573; P= .013).
The net CO2-C efflux from soils co-amended with biochar and manure (measured) were
significantly (P < .05) lower than the sum of the net CO2-C evolved from the corresponding sole
Table 2. Analysis of variance for cumulative C mineralized (CCM), applied C mineralized (ACM), sizes of the
labile and stable C pools (Cl and Cs, respectively) estimated by the double-exponential model as affected by
biochar (0, 20 and 40 t ha−1), manure (0, 13 and 26 t ha−1) and N fertilizer (0 and 90 kg−1 soil).
Source of variance df CCM ACM Cl Cs
Biochar (B) 2 <0.001 <0.001 <0.001 <0.001
Manure (M) 2 <0.001 <0.001 <0.001 <0.001
Fertilizer (F) 1 0.583 0.140 <0.001 <0.001
B x M 4 0.006 <0.001 0.099 0.108
B x F 2 0.577 0.080 0.693 0.749
M x F 2 0.234 0.557 0.027 0.022
B x M x F 4 <0.001 <0.004 0.003 0.002
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2599
Figure 2. Applied C mineralized in soils amended with sole and/or combined biochar (B) or manure (M) with or without N fertilizer
after 56 days incubation. Same letter(s) above the bars indicate no significant difference between treatments at p = .05. Vertical
bars represent standard error of the means (n = 3). B0, B20 and B40 are B rates at 0, 20 and 40 t ha-1, respectively. M0, M13 and
M26 are M rates at 0, 13 and 26 t ha-1, respectively. N fertilizer rates are 0 and 90 kg kg-1 soil.
Figure 3. Relationship between percent of applied carbon mineralized (ACM) and C/N ratio of soil-amendment mixtures.
biochar and manure treated soils (expected), with or without N application. The calculated AE
values ranged from −7 to −35%, with the most negative value recorded in the B40M13F90 treatment.
Generally, AE values tended to be more negative in soils co-amended with biochar and manure that
also received N fertilizer application.
Readily oxidizable C (ROC) and mineral N
Sole biochar and manure application resulted in significant (P < .05) increase in ROC content of the
soils compared with the unamended control, with ROC of manure, treated soils being significantly
higher (P < .05) than those of biochar-amended soils (Figure 4). The ROC contents of the soils were
positively and significantly correlated with initial C applied (r = 0.635; P= .005), ICM rate (r = 0.568;
2600 D. E. DODOR ET AL.
Figure 4. Effect of sole and/or combined biochar (B) or manure (M) with or without N fertilizer on readily oxidizable C content of
the soils after 56-d incubation period. Same letter(s) above the bars indicate no significant difference between treatments at p =
.05. Vertical bars represent standard error of the means (n = 3). B0, B20 and B40 are B rates at 0, 20 and 40 t ha-1, respectively. M0,
M13 and M26 are M rates at 0, 13 and 26 t ha-1, respectively. N fertilizer rates are 0 and 90 kg kg-1 soil.
P= .013), CCM (Figure 5; r = 861; P < .001) and biochar application rate (r = 0.536; P < .023), but not
with manure application rate (r = 0.414; P= .088).
The amount of mineral N (NH4 + NO3) extracted from the soils after 56-d incubation period ranged
from 39.3 mg kg−1 soil in the B40M13F0 to 140 mg kg−1 soil in the B40M0F90 treatments (Figure 6).
Generally, higher amounts of mineral N were produced in soils amended with sole biochar and manure,
with or without N fertilizer application, relative to the control, resulting in positive net N mineralization
in all sole-amended soils. Net N immobilization was observed mostly in soils co-amended with biochar
and manure without N fertilizer application. The mineral N content of the soils were negatively and
significantly correlated with AE values (Figure 7; r = – 0.781; P= .022). Three-way ANOVA indicated
that the amount of mineral N produced was significantly influenced by biochar, manure and fertilizer,
as well as their two and three-factor interactions.
Figure 5. Relationship between total amount of CO2-C evolved and readily oxidizable C content of the soils after 56-d incubation
period.
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2601
Figure 6. Effect of sole and/or combined biochar (B) or manure (M) with or without N fertilizer on mineral N content of the soils
after 56-d incubation period. Same letter(s) above the bars indicate no significant difference between treatments at p = .05.
Vertical bars represent standard error of the means (n = 3). B0, B20 and B40 are B rates at 0, 20 and 40 t ha-1, respectively. M0,
M13 and M26 are M rates at 0, 13 and 26 t ha-1, respectively. N fertilizer rates are 0 and 90 kg kg-1 soil.
Figure 7. Relationship between attributable effect (AE) and mineral N content of the soils at the end of 56-d incubation period.
Kinetics of carbon mineralization
The kinetic parameters obtained by fitting the cumulative CO2-C evolved from the treated soils to
the double-exponential first-order model are shown in Table 3. The estimated size of the labile
C pool (Cl) ranged from 82 mg kg
−1 soil in the control soil to 260 mg kg−1 soil in the B40M26F90
treatment (Table 3). Generally, sole manure-amended soils recorded significantly (P < .05) larger Cl
compared with the sole biochar amended soils, with or without N fertilizer application. Co-
application of manure and biochar increased Cl pool compared to sole biochar treatments. The Cl
2602 D. E. DODOR ET AL.
Table 3. Size, decomposition rates and half-lives of the labile and stable C pools (Cl, kl, Cs and ks, respectively) estimated by the
double-exponential model in soils amended with biochar (B) at 0, 20 and 40 t ha−1, manure (M) at 0, 13 and 26 t ha−1, combined
B and M (B at 20 or 40 t ha−1 plus M at 13 or 26 t ha−1) with or without N fertilizer (F) at 0 and 90 kg ha−1 after 56 days of
incubation.
Half-life Half-life Cl/CT Cs/CT Cl/Cs kl
Treatment Cl (mg kg
−1) kl (day
−1) (day) C (mg kg−1) k (day−1s s ) (day) R
2 (%) (%) (%) /ks
Control
B0M0F0 82 0.356 2.28 2518 1.5E-03 466 0.994 3.2 97 3.3 238
B0M0F90 145 0.240 3.05 2458 1.0E-03 752 0.995 5.6 94 5.9 231
Sole applied biochar or manure
B0M13F0 197 0.272 2.30 3394 1.9E-03 360 0.998 5.5 95 5.8 141
B0M13F90 186 0.298 2.40 3405 2.0E-03 359 0.995 5.2 95 5.5 149
B0M26F0 212 0.310 2.22 4370 1.8E-03 389 0.996 4.6 95 4.8 173
B0M26F90 206 0.321 2.31 4375 2.1E-03 328 0.997 4.5 96 4.7 151
B20M0F0 112 0.392 1.97 5894 9.2E-04 762 0.990 1.9 98 1.9 427
B20M0F90 142 0.336 1.80 5863 1.1E-03 655 0.992 2.4 98 2.4 309
B40M0F0 155 0.343 2.11 8276 8.1E-04 882 0.995 1.8 98 1.9 425
B40M0F90 170 0.348 2.06 8261 5.7E-04 1239 0.988 2.0 98 2.1 612
Co-applied biochar and manure
B20M13F0 170 0.322 2.26 6826 1.4E-03 508 0.992 2.4 98 2.5 234
B20M13F90 213 0.292 2.49 6783 7.5E-04 930 0.997 3.1 97 3.1 391
B20M26F0 237 0.241 2.79 7750 1.3E-03 552 0.995 3.0 97 3.1 190
B20M26F90 197 0.376 2.09 7793 1.6E-03 457 0.994 2.5 98 2.5 241
B40M13F0 211 0.324 2.36 9211 7.6E-04 934 0.994 2.2 98 2.3 427
B40M13F90 207 0.281 2.13 9215 9.8E-04 710 0.993 2.2 98 2.2 286
B40M26F0 212 0.331 2.43 10200 1.1E-03 643 0.999 2.0 98 2.1 303
B40M26F90 260 0.261 2.76 10152 8.7E-04 806 0.998 2.5 98 2.6 298
LSD 28 0.101 0.67 27 3.5E-04 213
values expressed as a percent of the total organic C in the sole manure amended soils ranged from
4.5% to 5.5% compared to 1.8–2.4% for the sole biochar amended soils. The corresponding values for
soils co-amended with biochar and manure ranged from 2.0% to 3.1% of the total organic C.
All treatments had larger proportion of their organic C apportioned to the stable C pool (Cs), with values
ranging from 2.24 to 10.15 g C kg−1 soil; this is equivalent to ≥94% of the initial C applied. The Cl/Cs ratio
ranged from 1.9% to 5.9%, with manure-amended soils recording higher values compared to sole and/or
combined biochar and manure amended soils (Table 3). The size of both Cl and Cs pools increased with
increasing application rates of the amendments (Table 3). Based on the double-exponential model, the
amount of C sequestrated in the Cs pools in treatments containing biochar, solely or in combination with
manure were 2.3–4.2 times higher than those of sole manure treatments or soil alone. The Cl pool was
positively and significantly correlated with ICM (r = 0.921; P < .001), CCM (r = 0.785; P < .001) and ROC (r
= 0.688; p < .01) (Table 4). As expected, theCs pool was positively and significantly correlated with ICM (r =
0.623; P < .01) and CCM (r = 0.593; P < .01), but not with ROC (r = 0.432) (Table 3). Three-way ANOVA
indicated that estimated Cl and Cs pools were influenced by biochar, manure, N fertilizer and their three
factor interactions (Table 2).
Generally, the rate constant kl for the Cl pool for the biochar and biochar-manure-amended soils were
lower than those for the sole manure-amended soils (Table 3). Slower ks values were recorded for the sole
biochar treated soils, with kl/ks ratio ranging from 141 to 612. The half-lives of the Cl pools were narrow,
with values ranging from 1.8 to 3.1 days, whereas those of the stableCs pools were wide, ranging from 328
to 1239 days (Table 3). The half-lives of the Cs pool for all treatments containing biochar, either solely or
in combination with manure were ≥1.4 folds longer than those of the sole manure amended soils.
Discussion
Cumulative c mineralization
The rapid increase in C mineralization immediately after incubation, especially during the first 7-d is
consistent with the results of Ajwa and Tabatabai (1994) who reported that 45 – 47% of the organic
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2603
Table 4. Correlation coefficients among measured soil
process and C pools estimated by the double-
exponential model.
Soil Process Cl Cs
ICM 0.921*** 0.623**
CCM 0.785*** 0.593**
ACM 0.171ns −0.673**
ROC 0.688** 0.432ns
AE 0.297ns 0.181ns
C/N ratio 0.293ns 0.808***
Mineral N −0.355ns −0.456*
ICM, Initial C mineralization rate; CCM, Cumulative
C mineralized; ACM, Applied C mineralized; AE,
Attributable effect; ROC, Readily oxidizable C; Cl
and Cs, labile and stable C pools, respectively; ns,
not significant; *, ** and *** significant at p ≤ 0.05,
0.01 and 0.001, respectively.
C in cow manure was mineralized during the first week of a short-term incubation study. This
increase in CO2-C production is often attributed to changes in soil humidity and temperature
following rewetting and availability of easily biodegradable organic C, which results in increased
microbial activity and high CO2 release rates (Borken and Matzner 2009; Quyang, Yu, and Zhang
2014; Ribeiro et al. 2010). Other researchers have also reported that rewetting of soils disrupts soil
aggregates, releasing hitherto protected and unavailable organic C for rapid mineralization by
microbial communities (Kieft, Soroker, and Firestone 1987; Lundquist, Jackson, and Scow 1999).
The significant increase in CO2-C efflux in the biochar amended compared to the unamended
soils indicates that the biochar contained some amount of readily mineralizable C that was assessible
to the microbes, as has been reported by other workers (Ameloot et al. 2013; Qayyum et al. 2012).
The results, however, contradict Grunwald, Kaiser, and Ludwig (2016) who reported comparable
C mineralization rates in biochar amended compared to the control soil. The positive correlation
between CCM and application rates of the amendments could be due to stimulation of microbial
activity by the increased supply of readily mineralizable organic C and other limiting nutrients, such
a P and N (Ribeiro et al. 2010).
Heterotrophic microorganisms responsible for organic C mineralization in soils utilize dissolved
and readily available organic C as source of C, reducing equivalent and energy for cell biosynthesis
and growth (Sylvia et al. 2005). The higher ROC content of the manure amended soils indicates that
KMnO4 indeed oxidized the easily mineralizable organic C components of the soil-mixtures, of
which manure contained higher amounts compared to biochar. This higher amount of readily
mineralizable C content of the soil-mixtures due to manure application resulted in significantly
higher ICM and CCM rates in soils amended with manure, solely or combined with biochar
compared to sole biochar treated soils. Furthermore, the increased ICM with increasing proportion
of manure in the soil-mixtures at a fixed biochar rate is another strong indication that manure
exerted considerable influence on C mineralization, especially at the initial stages of the incubation.
The results further suggest that ROC content, as measured by susceptibility of SOC to oxidation by
KMnO4, can be used as an index of chemical reactivity, bioavailability and physical accessibility of
organic C substrates to microorganisms in biochar-manure-amended sandy soils. Similarly, Dodor
et al. (2018) reported a close association between water-extractable OC (WEOC) and net CO2-C
evolution in these soils and suggested the use of WEOC as an index of labile C content and an
important source of C for microorganisms in soils.
Microbial mineralization of carbon is influenced by the proportion of labile organic C pool and
N in a given amendment (Jien et al. 2017). Therefore, changes in composition due to biochar
application led to differences in the nature and amount of readily mineralizable organic C and other
nutrients, especially N in the soil-mixtures, resulting in the observed significantly higher
2604 D. E. DODOR ET AL.
C mineralization rates in the manure amended compared to biochar-treated soils (Quyang, Yu, and
Zhang 2014; Ribeiro et al. 2010).
Applied c mineralized (ACM) and attributable effect (AE)
The ACM for the sole biochar treatments, which is the total amount of CO2 efflux expressed as
a percentage of added C, were lower than that for the control. The significantly less C mineralization
in the biochar compared to manure amended soils indicates that sole manure application resulted in
more C mineralization whereas net C sequestration occurred in the sole biochar or biochar-manure-
treated soils. Zimmerman, Gao, and Ahn (2011) reported similar finding in biochar amended
compared to unamended control soils. Zhao, Coles, and Wu (2015) also reported lower ratios of
mineralized to total C in biochar treated soils, indicating larger C sequestration in the biochar-soil
mixture compared to the control soil without amendment.
The biochar mineralization rates reported in the present study are in the range reported by
Baldock and Smernik (2002) for C mineralization in red pine wood biochar produced at pyrolysis
temperature of 305°C. The mineralization rates are higher than those of Hamer et al. (2004) who
reported C losses ranging from 0.3% to 0.8% in three biochars in a 60-day incubation study, and
Kuzyakov et al. (2009) who measured mineralization rates between 1.8% and 2.1% for biochar
incubated in a loess-soil during the first 2 months of incubation. The mineralization rates are,
however, lower than those of Nguyen and Lehmann (2009) who reported 16% mineralization of
corn-derived biochar after one-year incubation.
It is apparent that the negative AE values in the co-amended biochar-manure soils, which
indicates negative C mineralization, was due to the low availability of readily mineralizable organic
C in the mixtures because of biochar application. This assertion was supported by the significantly
higher ICM and CCM in soils amended with manure, either sole or combined with biochar, which
increased with increasing manure application rate at a fixed biochar rate. In addition, the positive
correlation between ACM and manure application rate, coupled with the significant negative
correlation between ACM and biochar application rates offer credence to this assertion. The results
suggest that manure provided more readily available OC that stimulated microbial activity, leading
to the slight but insignificant increase in CO2-C efflux in the combined biochar-manure relative to
the sole-amended soils. However, application of biochar might have stabilized the labile C in the
mixture through sorption onto the organic coatings on the surface of biochar, by incorporation into
its mineral fractions or absorption of the evolved CO2-C onto the porous and large surface area of
the biochar, as has been reported by other researchers (Hagemann, Joseph, and Schmidt et al. 2017;
Jien et al. 2017; Keith and Singh 2011). The results further suggest that co-application of biochar and
manure can provide the required nutrients for crop growth through mineralization while increasing
the amount of C sequestrated in sandy soils.
Generally, interaction between C and N in amended soils determined the net direction of
C mineralization process. Thus, the lack of influence of N application rates on ICM, coupled with
the positive correlation between ICM and C/N ratio of the soil-mixtures strongly suggests that
microbial populations were primarily limited by availability of C during the initial stages of
incubation (Knapp, Elliott, and Campbell 1983; Reinertsen et al. 1984). The provision of copious
amount of labile C from biochar and manure, therefore fueled higher ICM rates in the amended soils
compared to the control and N only amended soils. However, as postulated by Liebig’s Law of
Minimum (Sylvia et al. 2005) and the stoichiometric balance between the two nutrients, after
microbial requirement for C was met, N became the limiting nutrient as mineralization progressed.
The purported shift in nutrient requirement as C mineralization continued was supported by the
significant negative correlation between ACM and C/N ratio, indicating that the decreased ACM at
the end of the incubation period was due to increased C/N ratio in the combined biochar-manure-
amended soils without N fertilizer application, leading to mineral N limitation, culminating in
reduced C mineralization. Furthermore, the negative correlation between AE and C/N ratio coupled
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2605
with that between AE and mineral N content of the soils are also strong indications that microbial
population were limited by N rather than C supply at the end of 56-d incubation period.
Although the results indicated that none of the parameters measured were influenced by
N fertilizer application rates, they were significantly correlated with C/N ratio of the soil-mixtures.
As noted above, because of the stoichiometric relationship between the amount of C and N that can
be assimilated by microbes, it is conceivable that C/N ratio would be a better indicator of
N requirement and/or limitation rather than N application rates. The results indicate that the use
of N fertilizer application rate to evaluate the influence of N on microbial population and activity
could lead to erroneous conclusions. Therefore, when predicting the potential effects of N fertilizer
on C mineralization and sequestration, more attention should be paid to C/N ratio of the soil-
mixtures, rather than N application rate.
Kinetics of C mineralization
The high R2 values obtained in all treatments using the double-exponential model indicate that the
model is a useful approximation of C mineralization in manure and biochar amended soils, and
suggest that the C mineralization process was biphasic, with a smaller labile and larger stable
C pools, as have been reported previously by other authors (Qayyum et al. 2012; Zimmerman,
Gao, and Ahn 2011). This assertion was supported by the inflections in the exponential curves for
CCM, indicating that C mineralization occurred in two major stages, an initial increase in microbial
activity during which the easily degradable organic C were rapidly exhausted, and a second stage
where microbes shifted to use the more recalcitrant materials until a new steady-state was established
in the system (Ajwa and Tabatabai 1994; Ribeiro et al. 2010; Rivas et al. 2014).
The proportion of labile and recalcitrant organic C pools in an organic amendment determines its
turnover rate and C sequestration potential when applied to soils. The low Cl/Cs ratio of the
estimated C pools is in consonance with the results of Zimmerman, Gao, and Ahn (2011) who
described the labile C pool as consisting of smaller sized volatile aliphatic compounds with low
C and higher oxygen components that were readily mineralized, and a larger stable C pool made up
of nonvolatile aromatic C and low oxygen compounds that were mineralized more slowly. Using
a sequential C fractionation procedure, Bolan et al. (2012) reported that the proportion of labile
C pool (resin and 0.1 M NaOH extractable) in biochar was very small compared to that for the stable
C pool (1.0 M NaOH extractable). Bernal et al. (1998) reported that the labile C fraction of organic
residues decomposed faster than the stable C fractions. The stronger positive correlation between
ICM and the labile C pool, Cl compared with that for the recalcitrant C pool, Cs suggests that the
easily mineralizable labile C pool exerted stronger influence on the C mineralization process,
especially at the initial stages of the incubation.
Soil microorganisms are responsible for OC mineralization, therefore any useful kinetic para-
meter derived from empirical equations must correlate with experimentally measurable microbio-
chemical properties of the soil (Dodor 2002; Dodor et al. 2018). The significant correlation between
the estimated indices of easily biodegradable organic C pools (Cl pool) and ICM, CCM and ROC
affirmed our experimental results indicating that labile C was an important source of energy for the
microorganisms, and that ROC can be used as a good proxy for estimating the size of the labile
C content of manure and biochar amended soils. Similarly, Dodor et al. (2018) suggested the use of
WEOC as a good estimate of labile and readily mineralizable C content of biochar amended soils.
Saviozzi, Vanni, and Cardelli (2014) also reported a significant relationship between readily miner-
alizable C pools and the amount of C mineralized in urban soils during a 25 days incubation
experiment. The close agreement between CCM from experimental results and the estimated Cl
pools also suggest that the observed increase in C mineralization with increasing manure and
biochar application rates were due to the increased supply of readily mineralizable C (Cross and
Sohi 2011; Fernández et al. 2014).
2606 D. E. DODOR ET AL.
The slower kinetic rate constants (kl and ks) of the labile and stable C pools in the biochar
compared to manure amended soils, suggest that the chemical nature of mineralizable OC in the two
amendments are different. The kl and ks values are also consistent with the experimental results
showing higher CO2-C evolution in the manure-amended soils, suggesting that biochar is relatively
inert in the soils (Kuzyakov et al. 2009), which led to reduced CO2-C efflux. The high kl/ks ratios
indicate faster mineralization of the readily biodegradable C pool in the amendments leaving behind
a larger and more refractive Cs pool with slower kinetic lost constant (ks) and longer half-life (Zhao,
Coles, and Wu 2015; Zimmerman, Gao, and Ahn 2011).
The shorter half-lives of the manure compared with biochar-treated soils are due to the varied
nature and quality of C in the organic amendments (Flavel and Murphy 2009). The calculated
shorter half-lives of the Cl pools and the longer half-life of the stable Cs pool suggest a rapid
mineralization of the easily biodegradable organic C pools (Cl), leaving behind ≥94% of relatively
stable C pool with reduced biodegradability, subsequently leading to greater C sequestration. The
consistency between modeled kinetic parameters and experimental CO2-C evolution suggest that co-
application of biochar can promote an initial rapid mineralization of co-applied biochar and manure
to release nutrients needed by plants but sequester larger amount of the applied amendment in the
refractive Cs pool, resulting in larger amount of C sequestration and increased OC content of sandy
soils.
Conclusions
This study evaluated the kinetics of C mineralization and sequestration in a sandy soil amended with
sole and/or combined biochar and cattle manure, with or without N fertilizer application. Biochar
application, solely or in combination with manure resulted in lower ACM values, indicating
C sequestration in the soils. Negative attributable effect (AE) of co-application of biochar and
manure on C mineralization was observed relative to the sole treatments. Both AE and ACM were
negatively correlated with C/N ratio and mineral N content of the soil-amendment mixtures,
indicating that microbial population were limited by N availability. The kinetic parameters obtained
using the double-exponential model were consistent with experimental CO2-C evolution and
indicated that ≥94% of the initial C applied was apportioned to the stable Cs pool with slower rate
constant and longer half-lives. The results suggest that co-application of biochar can promote initial
faster mineralization to release plant nutrients but sequester larger amount of the applied amend-
ment in the refractive Cs pool, resulting in larger amount of C sequestration in the soils. The best
combination of the biochar and manure that can maximize C sequestration and sustain crop
production in these soils require further investigation.
Acknowledgments
The authors are indebted to Professor Dr. Samuel G. K. Adiku of the Department of Soil Science, University of
Ghana (UG) for reviewing and offering constructive criticisms of the draft manuscript. The authors also wish to
thank the laboratory technicians at the Department of Soil Science, UG, for their assistance in laboratory analysis.
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit
sectors.
Conflicts of interest
The authors declare that there is no conflict of interest regarding the publication of this paper.
ORCID
Daniel E. Dodor http://orcid.org/0000-0002-0640-2815
Yahaya J. Amanor http://orcid.org/0000-0001-7678-9800
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2607
Abena Asamoah-Bediako http://orcid.org/0000-0001-6812-5203
Dilys S. MacCarthy http://orcid.org/0000-0002-8062-3499
Delali B.K. Dovie http://orcid.org/0000-0002-2165-1721
References
Agegnehu, G., A. M. Bass, P. N. Nelson, B. Muirhead, G. Wright, and M. I. Bird. 2015. Biochar and biochar-compost
as soil amendments: Effects on peanut yield, soil properties and greenhouse gas emissions in tropical North
Queensland, Australia. Agriculture, Ecosystem and Environment 213:72–85. doi:10.1016/j.agee.2015.07.027.
Ajwa, H. A., and M. A. Tabatabai. 1994. Decomposition of different organic materials in soils. Biology and Fertility of
Soils 18:175–82. doi:10.1007/BF00647664.
Ameloot, N., E. E. Graber, F. G. A. Verheijen, and S. de Neve. 2013. Interactions between biochar stability and soil
organisms: Review and research needs. European Journal of Soil Science 64:379–90. doi:10.1111/ejss.12064.
Angin, D., and S. Şensöz. 2014. Effect of pyrolysis temperature on chemical and surface properties of biochar of
rapeseed (Brassica napus L.). International Journal of Phytoremediation 16 (7–8):684–93. doi:10.1080/
15226514.2013.856842.
Baldock, J. A., and R. J. Smernik. 2002. Chemical composition and bioavailability of thermally altered pinus resinosa
(Red Pine) wood. Organic Geochemistry 33:1093–109. doi:10.1016/S0146-6380(02)00062-1.
Bauer, P. J., J. R. Frederick, J. M. Novak, and P. G. Hunt. 2006. Soil CO2 flux from a Norfolk loamy sand after 25 years
of conventional and conservation tillage. Soil and Tillage Research 90:205–11. doi:10.1016/j.still.2005.09.003.
Bernal, M. P., M. A. Sanchez-Monedero, C. Paredes, and A. Roig. 1998. Carbon mineralization from organic wastes at
different composting stage during their incubation with soil. Agriculture, Ecosystem and Environment 69:175–89.
doi:10.1016/S0167-8809(98)00106-6.
Blair, G. J., R. D. Lefroy, and L. Lisle. 1995. Soil carbon fractions based on their degree of oxidation, and the
development of a carbon management index for agricultural systems. Crop and Pasture Science 46 (7):1459–66.
doi:10.1071/AR9951459.
Bolan, N. S., A. Kunhikrishnan, G. K. Choppala, R. Thangarajan, and J. W. Chung. 2012. Stabilization of carbon in
composts and biochar in relation to carbon sequestration and soils fertility. Science of the Total Environment
424:264–70. doi:10.1016/j.scitotenv.2012.02.061.
Borken, W., and E. Matzner. 2009. Reappraisal of drying and wetting effects on C and N mineralization and fluxes in
soils. Global Change Biology 15:808–24. doi:10.1111/gcb.2009.15.issue-4.
Brewer, C. E., K. Schmidt-Rohr, J. A. Satrio, and R. C. Brown. 2009. Characterization of biochar from fast pyrolysis
and gasification systems. Environmental Progress and Sustainable Energy 28:386–96. doi:10.1002/ep.10378.
Budai, A., L. Wang, M. Gronli, L. T. Strand, M. J. Antal, S. Abiven, and D. P. Rasse. 2014. Surface properties and
chemical composition of corncob and miscanthus biochars: Effects of production temperature and method. Journal
of Agricultural and Food Chemistry 62 (17):3791–99. doi:10.1021/jf501139f.
Cross, A., and S. P. Sohi. 2011. The priming potential of biochar products in relation to labile carbon contents and soil
organic matter status. Soil Biology and Biochemistry 43:2127–34. doi:10.1016/j.soilbio.2011.06.016.
Dodor, D. E. 2002. Enzyme activities in soils as affected by long-term cropping systems. Iowa State University
retrospective theses and dissertations, 990. http://lib.dr.iastate.edu/rtd/990.
Dodor, D. E., Y. J. Amanor, F. T. Attor, T. A. Adjadeh, D. Neina, and M. Miyittah. 2018. Co-application of biochar
and cattle manure counteract positive priming of carbon mineralization in a sandy soil. Environmental Systems and
Research 7 (1):1–8. doi:10.1186/s40068-018-0108-y.
Fernández, J. M., M. A. Nieto, E. G. López-de-Sá, G. Gascó, A. Méndez, and C. Plaza. 2014. Carbon dioxide emissions
from semi-arid soils amended with biochar alone or combined with mineral and organic fertilizers. Science of the
Total Environment 482–483:1–7. doi:10.1016/j.scitotenv.2014.02.103.
Flavel, T. C., and D. V. Murphy. 2009. Carbon and nitrogen mineralization rates after application of organic
amendments to soils. Journal of Environmental Quality 35:183–93. doi:10.2134/jeq2005.0022.
Glaser, B., J. Lehmann, and W. Zech. 2002. Ameliorating physical and chemical properties of highly weathered soils in
the tropics with charcoal–A review. Biology and Fertility of Soils 35 (4):219–30. doi:10.1007/s00374-002-0466-4.
Grunwald, D., M. Kaiser, and B. Ludwig. 2016. Effect of biochar and organic fertilizers on C mineralization and
macro-aggregate dynamics under different incubation temperatures. Soil and Tillage Research 164:11–17.
doi:10.1016/j.still.2016.01.002.
Hagemann, N., S. Joseph, H. Schmidt, et al. 2017. Organic coating on biochar explains its nutrient retention and
stimulation of soil fertility. Nature Communications 8:1089. doi:10.1038/s41467-017-01123-0.
Hamer, U., B. Marschner, S. Brodowski, and W. Amelung. 2004. Interactive priming of black carbon and glucose
mineralization. Organic Geochemistry 35:823–30. doi:10.1016/j.orggeochem.2004.03.003.
Jien, S. H., W. C. Chen, Y. S. Ok, and Y. M. Awad. 2017. Short-term biochar application induced variations in C and
N mineralization in a compost-amended tropical soil. Environmental Science and Pollution Research 25:2517.
2608 D. E. DODOR ET AL.
Keith, A., and B. P. Singh. 2011. Interactive priming of biochar and labile organic matter mineralization in a
smectite-rich soil. Environmental Science and Technology 45:9611–18. doi:10.1021/es202186j.
Kieft, T., E. Soroker, and M. Firestone. 1987. Microbial biomass response to rapid increase in water potential when dry
soil is wetted. Soil Biology and Biochemistry 19:119–26. doi:10.1016/0038-0717(87)90070-8.
Knapp, E. B., L. F. Elliott, and G. S. Campbell. 1983. Microbial respiration and growth during the decomposition of
wheat straw. Soil Biology and Biochemistry 15:319–23. doi:10.1016/0038-0717(83)90077-9.
Kuzyakov, Y., I. Subbotina, H. Chen, I. Bogomolova, and X. Xu. 2009. Black carbon decomposition and incorporation
into soil microbial biomass estimated by 14C labeling. Soil Biology and Biochemistry 41:210–19. doi:10.1016/j.
soilbio.2008.10.016.
Laird, D. A., P. Fleming, D. D. Davis, R. Horton, B. Wang, and D. L. Karlen. 2010. Impact of biochar amendments on
the quality of a typical midwestern agricultural soil. Geoderma 158:443–49. doi:10.1016/j.geoderma.2010.05.013.
Lehmann, J., and S. Joseph. 2009. Biochar for environmental management: An introduction. In Biochar for environ-
mental management: Science and technology, ed. J. Lehmann and S. Joseph, 1–12. London: Earthscan.
Lu, W., W. Ding, J. Zhang, Y. Li, J. Luo, N. Bolan, and Z. Xie. 2014. Biochar suppressed the decomposition of organic
carbon in a cultivated sandy loam soil: A negative priming effect. Soil Biology and Biochemistry 76:12–21.
doi:10.1016/j.soilbio.2014.04.029.
Lundquist, E., L. Jackson, and K. Scow. 1999. Wet dry cycles effect on DOC in two California agricultural soils. Soil
Biology and Biochemistry 31:1031–38. doi:10.1016/S0038-0717(99)00017-6.
Luo, Y., M. Durenkamp, M. De Nobili, Q. Lin, and P. C. Brookes. 2011. Short term soil priming effects and the
mineralization of biochar following its incorporation to soils of different pH. Soil Biology and Biochemistry
43:2304–14. doi:10.1016/j.soilbio.2011.07.020.
Molina, J. A. E., C. E. Clapp, and W. E. Larson. 1980. Potentially mineralizable nitrogen in soil: The simple exponential
model does not apply to the first 12 weeks of incubation. Soil Science Society of America Journal 44:442–43.
doi:10.2136/sssaj1980.03615995004400020054x.
Mulvaney, R. L. 1996. Nitrogen–Inorganic Forms. In Methods of soil analysis, part 3, chemical methods 3rd edition’, ed.
D. L. Sparks, et al., 1123–84. Madison, WI, USA: SSSA/ASA.
Nguyen, B. T., and J. Lehmann. 2009. Black carbon decomposition under varying water regimes. Organic Geochemistry
40:846–53. doi:10.1016/j.orggeochem.2009.05.004.
Novak, J., K. Cantrell, and D. Watts. 2013. Compositional and thermal evaluation of lignocellulosic and poultry litter
chars via high and low temperature pyrolysis. Bioenergy Research 6:114–30. doi:10.1007/s12155-012-9228-9.
Novak, J. M., W. J. Busscher, D. W. Watts, D. A. Laird, M. A. Ahmedna, and M. A. S. Niandou. 2010. Short-term CO2
mineralization after additions of biochar and switchgrass to a typic kandiudult. Geoderma 154:281–88. doi:10.1016/
j.geoderma.2009.10.014.
Qayyum, M. F., D. Steffens, H. P. Reisenauer, and S. Schbert. 2012. Kinetics of carbon mineralization of biochars
compared with wheat straw in three soils. Journal of Environmental Quality 41:1210–20. doi:10.2134/jeq2011.0058.
Quyang, L., L. Yu, and R. Zhang. 2014. Effects of amendment of different biochars on soil carbon mineralization and
sequestration. Soil Research 52:46–54. doi:10.1071/SR13186.
Rajapaksha, A. U., M. Vithanage, M. Zhang, M. Ahmad, D. Mohan, S. X. Chang, and Y. S. Ok. 2014. Pyrolysis
condition affected sulfamethazine sorption by tea waste biochars. Bioresource Technology 166:303–08. doi:10.1016/j.
biortech.2014.05.097.
Reinertsen, S. A., L. F. Elliot, V. L. Cochran, and G. S. Campbell. 1984. Role of available carbon and nitrogen in
determining the rate of wheat straw decomposition. Soil Biology and Biochemistry 16:459–64. doi:10.1016/0038-
0717(84)90052-X.
Ribeiro, H. M., D. Fangueiro, F. Alves, E. Vasconcelos, J. Coutinho, R. Bol, and F. Cabral. 2010. Carbon-mineralization
kinetics in an organically managed cambic arenosol amended with organic fertilizers. Journal of Plant Nutrition and
Soil Science 173:39–45. doi:10.1002/jpln.v173:1.
Rittl, T. F., E. H. Novotny, F. C. Balieiro, E. Hoffland, B. J. R. Alves, and T. W. Kuyper. 2015. Negative priming of
native soil organic carbon mineralization by oilseed biochars of contrasting quality. European Journal of Soil Science
66:714–21. doi:10.1111/ejss.2015.66.issue-4.
Rivas, F. A., M. A. Tabatabai, D. C. Olk, and M. L. Thompson. 2014. Kinetics of short-term carbon mineralization in
roots of biofuel crops in soils. Biology and Fertility of Soils 50 (3):527–35. doi:10.1007/s00374-013-0870-y.
Rogovska, N., D. Laird, R. Cruse, P. Fleming, T. Parkin, and D. Meek. 2011. Impact of biochar on manure carbon
stabilization and greenhouse gas emissions. Soil Science Society of America Journal 75:871–79. doi:10.2136/
sssaj2010.0270.
Ronsse, F., S. van Hecke, D. Dickinson, and W. Prins. 2013. Production and characterization of slow pyrolysis biochar:
Influence of feedstock type and pyrolysis conditions. Global Change Biology Bioenergy 5:104–15. doi:10.1111/
gcbb.12018.
Saviozzi, A., G. Vanni, and R. Cardelli. 2014. Carbon mineralization kinetics in soils under urban environment.
Applied Soil Ecology 73:61–69. doi:10.1016/j.apsoil.2013.08.007.
Smider, B., and B. Singh. 2014. Agronomic performance of a high ash biochar in two contrasting soils. Agriculture,
Ecosystem and Environment 191:99–107. doi:10.1016/j.agee.2014.01.024.
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS 2609
Sohi, S. P., E. Krull, E. Lopez-Capel, and R. Bol. 2010. A review of biochar and its use and function in soil. Advances in
Agronomy 105:47–82.
Sylvia, D. M., C. Hartel, J. J. Fuhrmann, and D. A. Zuberer. 2005. Principles and applications of soil microbiology. 2nd
ed. Upper Saddle: Pearson.
Tang, J., W. Zhu, R. Kookana, and A. Katayama. 2013. Characteristics of biochar and its application in remediation of
contaminated soil. Journal of Bioscience and Bioengineering 116 (6):653–59. doi:10.1016/j.jbiosc.2013.05.035.
Troy, S. M., P. G. Lawlor, C. J. O’Flynn, and M. G. Healy. 2013. Impact of biochar addition to soil on greenhouse gas
emissions following pig manure application. Soil Biology and Biochemistry 60:173–81. doi:10.1016/j.
soilbio.2013.01.019.
Van de Voorde, T. F. J., T. M. Bezemer, J. W. Van Groenigen, S. Jeffery, and L. Mommer. 2014. Soil biochar
amendment in a nature restoration area: Effects on plant productivity and community composition. Ecological
Applications 24 (5):1167–77. doi:10.1890/13-0578.1.
Zhang, P., H. Sun, L. Yu, and T. Sun. 2013. Adsorption and catalytic hydrolysis of carbaryl and atrazine on pig
manure-derived biochars: Impact of structural properties of biochars. Journal of Hazardous Materials 244:217–24.
doi:10.1016/j.jhazmat.2012.11.046.
Zhao, R., N. Coles, and J. Wu. 2015. Carbon mineralization following additions of fresh and aged biochar to an
infertile soil. Catena 125:183–89. doi:10.1016/j.catena.2014.10.026.
Zimmerman, A. R., B. Gao, and M. Y. Ahn. 2011. Positive and negative carbon mineralization priming effects among
a variety of biochar-amended soils. Soil Biology and Biochemistry 43:169–1179. doi:10.1016/j.soilbio.2011.02.005.