Preparation and Plant-growth Efficiency Assessment of Biochars

國立屏東科技大學熱帶農業暨國際合作系
Department of Tropical Agriculture and International Cooperation
National Pingtung University of Science and Technology
博士學位論文
Ph.D. Dissertation
Preparation and Plant-growth Efficiency Assessment of
Biochars
指導教授: 黃武章(Wu-Jang, Huang)
研究生: 歐蒂娣(Odette Marie Varela Milla)
中華民國102年05 月16日
May 16, 2013

2
General Introduction
Literature Review
Identifying the Advantages of Using MSW Bottom Ash in Combination with
Rice Husk and Bamboo Biochar Mixtures as Soil Modifiers: Enhancement of
the Release of Polyphenols from a Carbon Matrix
Feasibility Study using Municipal Solid Waste Incineration Bottom Ash and
Biochar from Binary Mixtures of Organic Waste as Agronomic Materials
Agronomic Properties and Characterization of Rice Husk and Wood Biochars
and their Effect on the Growth of Water Spinach in a Field Test
The Effects of Rice Husk Biochar and its Silicon Content on Corn
(Zea mays L.) Growth
Effects of Pyrolyzation Temperature of Bamboo Biochars on the Germination
and Growth Rates of Zea Mays L. and Brassica Rapa

Definition:
▪ Biochar is commonly defined as charred organic matter,
produced with the intent to deliberately apply to soils
to sequester carbon and improve soil properties
(Lehmann and Joseph, 2009).
Organic Matters
(Wastes)
Carbonization Bio-Char ?
Activation
Activated Carbon
5

6
Biochar
Charcoal
Biochar vs. charcoal
Feedstock
Unlike regular charcoal
creation, biochar
creation helps mitigate
climate change via
carbon sequestration,
increasing soil fertility
in the process

Motivation
7
Biochar research is in its first steps and as such, substantially more data is required
before robust predictions can be made regarding the effects of biochar application to
soils, across a range of soils, climatic, and land management factors.
Concomitant with carbon sequestration, biochar is intended to improve soil properties
and soil functioning relevant to agronomic and environmental performance.
Hypothesized mechanisms were suggested but are not very clearly, for potential
improvement water and nutrient retention (as well as improved soil structure,
drainage) would be mainly enhanced.
Considering the multi-dimensional and crosscutting nature of biochar, an imminent
need is anticipated for a strong and balanced scientific review to effectively inform
policy development on the current state of knowledge with reference to biochar
application to soils.

Activated carbon: (Material) charcoal for application to soil (noun). Charcoal
produced to optimize its reactive surface area (e.g. by using steam during
pyrolysis).
Anthrosol: (count noun) A soil that has been modified profoundly through
human activities, such as addition of organic materials or household wastes,
irrigation and cultivation.
Biochar: (Concept) “charcoal (biomass that has been pyrolyzed in a zero or
low oxygen environment) for which, owing to its inherent properties,
scientific consensus exists that application to soil at a specific site is
expected to sustainably sequester carbon and concurrently improve soil
functions.
Black carbon: (noun) All C‐rich residues from fire or heat (including from
coal, gas or petrol).
8

Black Earth: (mass noun) Term synonymous with
Chernozem used (e.g. in Australia) to describe self‐mulching
black clays.
Char: (mass noun) 1. Synonym of ‘charcoal’; 2.
charred organic matter as a result of wildfire
(verb) synonym of the term ‘pyrolyze’ .
Charcoal: (mass noun) charred organic matter.
Chernozem: (count noun) A black soil rich in
organic matter; from the Russian ‘chernij’ meaning
‘black’ and ‘zemlja’ meaning ‘earth’ or ‘land’.
9

Coal: (mass noun) Combustible black or dark brown rock
consisting chiefly of carbonized plant matter, found mainly
in underground seams and used as fuel.
Organic carbon: (noun) biology C that was originally part
of an organism; (chemistry) C that is bound to at least one
hydrogen (H) atom.
Terra Preta: (noun) Colloquial term for a kind of
Anthrosol where charcoal (or biochar) has been applied
to soil along with many other materials, including pottery
shards, turtle shells, animal and fish bones, etc.
10

11
Carbon sequestration potential of biochar
The global flux of
CO2 from soils to the
atmosphere is in the
region of 60 Gt of C
per year.
The black numbers indicate how much carbon is stored in
various reservoirs, in billions of tons (GtC = Gigatons of
Carbon). The purple numbers indicate how much carbon
moves between reservoirs each year, i.e. the fluxes. The
sediments, as defined in this diagram, do not include the ~70
million GtC of carbonate rock and kerogen (NASA, 2008).
Figure 2.1 Diagram of the carbon cycle. (NASA, 2008).
The principle of
using biochar for
carbon (C)
sequestration is
related to the role of
soils in the C-cycle.
This CO2 is mainly the result
of microbial respiration
within the soil system as the
microbes decompose soil
organic matter (SOM).

12
Objectives
 To generate biochars from organic wastes, to analyze their concept
and origins, to investigate their key roles on agriculture application,
at the same time we aim to study the effect of production process on
plant germination rate and their potential uses with other industrial
solid wastes, such as bottom ash.

CO2
World carbon
dioxide emissions
are expected to
increase by 1.9
percent annually
between 2001 and
2025
N2O
Nitrous oxide (5
percent of total
emissions),
meanwhile, is
emitted from
burning fossil fuels
and through the use
of certain fertilizers
and industrial
processes.
CH4
Methane, comes
from landfills, coal
mines, oil and gas
operations, and
agriculture; it
represents 9 percent
of total emissions.
14

15
In a study by Rondon et al.
(2007), biochar addition to soils
has been shown to reduce the
emission of both CH4 and N2O.
They reported that a near complete
suppression of methane upon
biochar addition at an application
rate of 2% w w-1
These results indicate that the effect of biochar additions to
soils on the N cycle depend greatly on the associated changes
in soil hydrology and those thresholds of water content effects
on N2O production may be very important and would have to
be studied for a variety of soil-biochar-climate conditions.

16
Other relevant
minerals can occur
in the biomass, such
as silicon (Si), which
occurs in the cell
walls, mostly in the
form of silica (SiO2).
Making biochar from
biomass waste materials
should create no
competition for land
with any other land use
option such as food
production or leaving
the land in its pristine
state.
Biochar can
and should be
made from
biomass waste
materials.

17
Pyrolysis is the chemical
decomposition of an
organic substance by
heating in the absence of
oxygen.
Pyrolysis occurs spontaneously at
high temperatures (generally
above approximately 300°C for
wood, with the specific
temperature varying with
material).
It occurs in nature when vegetation
is exposed to wildfires or comes
into contact with lava from
volcanic eruptions.
At its most extreme, pyrolysis
leaves only carbon as the
residue and is called
carbonization
Source: www.carbonzero.ch

Table 2.1 Mean of post-pyrolysis feedstock residues resulting from
different temperatures and residence times (IEA, 2007).
Mode Conditions Liquid Biochar Syngas
Fast pyrolysis Moderate temperature, ~
500°C, short hot vapor
residence time of ~ 1 s
75% 12% 13%
Intermediate
Pyrolysis
Moderate temperature, ~
500°C, moderate hot vapor
residence time of 10 - 20 s
50% 20% 30%
Slow Pyrolysis
(Carbonization)
Low temperature, ~ 400°C,
very long solids residence
time
30% 35% 35%
Gasification
High temperature, ~ 800°C,
very long vapor residence
time
5% 10% 85%
18
With regard to
the use of biochar
as a soil
amendment and
for climate
change mitigation
it is clear that
slow pyrolysis,
would be
preferable, as this
maximizes the
yield of char, the
most stable of the
pyrolysis final
products.

19
The design was handed for mechanical
construction and assembly to a company in
Pingtung City and was completed on May 2010.
This system was able to pyrolyze from 1 to 3kg of
biomass (wood pellets, rice husk, and others) per
run.
The batch reactor vessel is
a stainless steel horizontal
tube with a diameter of 60
cm x 90 cm.
(1) Smoke chimney, (2a) stainless steel mixing
arm, (2b) biochar mixing discs, (3) Reactor
cover, (4) stainless steel pyrolysis drum, (5)
temperature sensor, (6) stainless steel tube
inserted in reactor wall perforation passed
though (7) valve for sensor (placed in the
lowest point of the reactor, inside drum
reaching floor and fire flame), (8) gas tank, (9)
gas-reactor valve, (10) gas feeder tube, (11) fire
plate, (12) reactor wheels.

20
(a) Front view of biochar reactor, (b) Movable capsule
inside the reactor, it separates the fire and the biomass
during pyrolysis, (c) Temperature sensor, can reach 1000
C∘, (d) Flat cover avoids oxygen exchange, (e) Concave
cover goes after flat cover, helps to direct the smoke
emitted while charring to the excess pipe, (f) Reactor
cover and excess pipe, (g) valve used to insert
temperature sensor during pyrolysis, (h) Inside of
reactor, (i) We count with 2 reactors for our research.
(a) Dried muskmelon waste, (b) Muskmelon waste
inside of the reactor, (c) Reactor feed by gas, (d)
and (e) Flat and concave covers, we can observe
how the charcoal is adhered to the flat cover after
pyrolysis process, (f) Reactor after biochar
production, (g) Final product: muskmelon biochar.

Biochar production from muskmelon
waste
1st test
Initial weight 1.293 kg
Final weight 0.447 kg
Loss 0.846 kg
Initial temperature 33∘C
Final temperature 195∘C
Time 96 minutes
21
1 tone of biomass
gives 400 kg of
biochar

23
Ideal biochar structure development with
highest treatment temperature.
(HTT): (a) increased proportion of aromatic C,
highly disordered in amorphous mass; (b)
growing sheets of conjugated aromatic carbon,
turbostratically arranged; (c) structure becomes
graphitic with order in the third dimension
(Emmerich et al., 1987)
20μm 200μm
The porous structure of biochar invites
microbial colonization. Source: (left photo)
S. Joseph; (right photo) Yamamoto, in
Lehmann and Joseph (2009).

24
phenols phenolic acids flavonoids anthocyanins

Polyphenols include several classes of
compounds, such as phenols, phenolic acids,
flavonoids, anthocyanins, and others, with
more complex structures, tannins and lignins.
The mixed combination of biochar and
polyphenols applied at 1.5 % w/w to compost
led to highest root yields (Jordan et al., 2011)
Niggli and Schmidt (2010) tested biochar in
Vineyards and found that grapes from
biochar-treated plots had a 10% higher
polyphenol content. Together with the much
higher amino acid content, this was an
indication of a greater aromatic quality of the
grapes, which is then passed into the wine.
18

Agricultural profitability
Management of pollution and
eutrophication risk to the
environment
Restoration of degraded land
Sequestration of C from the
atmosphere
26
The purpose of applying biochar to soil mainly falls into four broad
categories:

29
 To investigate the value of biochar and MSWIBA mixtures as soil
modifiers and determine their effects on plant growth, root yield and the
dry biomass weight of corn (Zea mays L.). And to find advantages to the
addition of biochar to the BA.

30
Polyphenolic compounds are the most important types of secondary
metabolites that perform an important role in the biosynthesis
process (Bennet and Wallsgrove, 1994).
Natural polyphenols are necessary compounds in the stimulus of
plant development and growth. Stimulus or inhibition capacity on
plant growth and development is closely correlated with the
concentration of Polyphenolic compounds used (Anghel, 2001).
In some cases, the presence of these compounds in low concentrations
can have a favorable effect on plant development. In other cases, when
concentrations are high, there is an inhibition effect (Popa et al.,
2007).

35
The soil sample used
for this experiment was
collected from the
National Pingtung
University of Science
and Technology field.
“Ultisol” clay type, is an
acidic soil with a pH of
4.02, organic matter (OM)
1.33, clay content 7%, silt
72%, sand 21%, organic
carbon (OC) 0.77.
In terms of increasing
plant growth, biochar with
various pore sizes may be
best suited to enhancing
the physical, chemical and
biological characteristics
of soils.

37
Each biochar was mixed
separately with soil and
bottom ash.
Trays were filled with
either soil or soil-biochar-
bottom ash
mixtures, randomly
placed on net house
benches and watered
before sowing the seeds.
For each bottom ash test,
7 pots were used with 4
replicates each (n=4)
Mixtures: 1- soil, 2-
bottom ash + soil, 3-
bottom ash + rice husk
400, 4- bottom ash + rice
husk 500, 5- bottom ash
+ bamboo 300, 6-
bottom ash + bamboo
600 and 7- bottom ash.
Plants were harvested
after one month.
They were cleaned, and
washed with DI water.
Excessive water was
removed to later obtain
the total weight.

Plants were washed, cut
into small pieces and dried
in an oven at 65°C for 72 h.
The dried material was
ground and passed through
a 250 Hm sieve mesh.
The total phenolics were
determined according to
the Folin-Ciocalteau
method (Rossi, 1965;
Waterhouse, 2002; Koffi et
al., 2007).
The samples were filtered
through a 0.45 mm
Millipore syringe filter
The total phenolics in the
filtrate were determined
colorimetrically.
A volume of 100 mL of
filtrate was added to 900
mL of distilled water, and
5 mL of 0.2 N Folin–
Ciocalteau reagent was
mixed.
Absorbance was read at 750
nm with a UV/VIs-105
Genesys spectrophotometer
(Thermo, USA).
The total phenolic content of
the samples were calibrated
using catechins mono-compound
and was expressed
as parts per million and
converted to (mg/L). All
measurements were performed
in duplicate.
38

Heavy metal analysis
(ICP) was carried out to
identify the properties of
the different bottom ashes
used.
The leaching extraction
procedure followed USA
EPA method # 1311 with
minor modifications
(EPA, 1990).
Five grams of ground and
weighed bottom ash were
put in a volumetric flask
together with 1000 ml of
distilled water and 5.7 ml
of acetic acid.
Samples were left for 18 h
in a toxicity
characteristics leaching
procedure (TCLP)
rotator.
After this procedure,
samples where filtered
and analyzed through a
Perkin-Elmer 3000-XL
inductively coupled
plasma (ICP-AES)
spectrometer.
39

The contents determined by ICP showed
that bottom ash from the three different
cities did not differ from each other in most
of the elements.
There were differences in only four
elements: Calcium > Lead > Sodium >
Iron (Ca > Pb > Na > Fe>).
Calcium constituted the largest proportion
of the elements present in the bottom
The pH of the bottom ash, when mixed
with water, was as follows: Pingtung =
4.92, Chiayi = 6.63 and Chunghua = 6.59.
There was not a high reduction in pH after
leaching of metals.
40
Elements Pingtung Chiayi Changhua
mg/L
Fe 285.3 - -
Al 54.3 - -
Si 74.7 48.5 38.6
Pb 317.0 0.0 0.1
Zn 107.3 6.7 39.4
Cd - - 0.0
Ni 0.7 0.2 0.3
Cr 0.9 0.0 -
Na 69.5 290.0 173.3
K 18.9 109.5 65.8
Sb 1.6 0.2 0.2
Ca 1099.0 2392.0 2481.0
Mn 11.6 3.2 3.1
Mg 30.2 49.9 47.7
Sr 3.5 6.2 5.9
Ba 0.5 0.6 0.5
Cu 2.0 2.5 4.1
“‐” means not detectable.

41
Bottom ash treatments
Pingtung Chiayi Chunghua
Mixed
matrix
% of germination
NF F NF F NF F
1 Soil 90 45 80 90 95 95
2 Bottom ash + soil 80 95 55 50 45 70
3
Bottom ash + rice
husk 400 100 100 75 70 85 90
4
Bottom ash + rice
husk 500 95 95 75 80 80 70
5
Bottom ash +
bamboo 300 90 95 70 80 85 70
6
Bottom ash +
bamboo 600 90 100 75 35 75 85
7 Bottom ash 65 70 - - - -
NF= no fertilizer was applied, F= use of fertilizer.
Germination results in treatments of bottom ash
binary mixtures showed that the treatment with the
most consistent results was the one source in
Pingtung City.
Rice husk biochar (400ºC) presented the highest
germination percentage in all treatments having no
differences among fertilizer applications and non-applications,
followed by bottom ash + rice husk
500, bottom ash + bamboo 300 and bottom ash +
bamboo 600.
Treatments with soil+biochar+bottom ash gave
better germination percentage than those were only
soil was used or in combination of bottom ash
showing seed germination inhibition.
Inhibition effect may perhaps have some
explanations: in this study the inhibiting effect of
bottom ash on seed germination was tested at high
concentrations, such as to reduce the germination
percentage

42
In our results of
plant growth we
found differences
among the 3 sources
of bottom ash in
combinations with
biochars (Figure a,b
and c).
Pingtung showed the
best results with
differences among
treatments and
fertilizer applications
(Bottom ash + IRRI
400 °C), bottom ash
applied alone
showed inhibition in
plant growth.
The lowest average
was observed in
Chunghua bottom
ash (Figure (c)).
Plant size of MSWI bottom ash and biochar mixed matrix treatments. (a), (b) and (c), graphs show the differences between
the three sources of bottom ash and their combinations with biochar with and without additions of fertilizer.

43
We proposed that this
interaction might
decrease the use of
fertilizer in agricultural
soils. Therefore, the
application of the
mixed matrix of
bottom ash and biochar
is ideal for these types
of soils as an organic
fertilizer amendment
and and also for its
polyphenol content.
From the analysis
performed, polyphenols
released from a
BA/biochar mixture
were found to have a
linear relationship with
the stem size quantified
in plants (see Figure
3.2).
We also observed that
the biomass weight was
proportional to the
polyphenol amount
(Figure 3.3).

With these results, we can state that bottom ash can be
used in combination with biochar. When these
materials are mixed the generation of polyphenols
increases.
Since the mixed matrix of bottom ash and biochar
releases a large amount of polyphenols, the use of
fertilizer is not needed.
We found that the use of fertilizer on the BA/biochar
mixture had a negative effect on plant growth.
Therefore, when assessing the efficiency of applying
biochar, the fertilizer should not be added, given that
the use of fertilizers increases the release of
polyphenols inhibiting plant growth.
When measuring root length and comparing it to the
addition of fertilizer, we observed that root length
decreased in the fertilized region (see Figure 3.4).
Effect of polyphenol on plant dried biomass
tissue before and after addition of fertilizer.
Effects of polyphenol on plant dried biomass tissue before
and after addition of fertilizer where Chunghua bottom ash
was applied

47
 To quantify the impact of: (1) rice husk biochar (RHB) with
MSWI bottom ash and (2) bamboo biochar (BB) with MSWI
bottom ash during germination and development of maize
seedlings, as well as plant growth and amount of biomass
produced.
 To determine if the mixtures prepared for this study may have
had a positive effect on the development of maize seedlings;
therefore, the use of binary mixtures of bottom ash and biochar
for plant growth may be feasible in Taiwan.

50
Different types of MSWI
bottom ash were obtained
at a processing facility
located in Pingtung
County.
Bottom ash from three
different cities (Pingtung,
Chiayi and Chunghua
City) was collected and
was air dried for 3 days at
room temperature
Then it was sieved using
two mesh sizes (mesh 1-
19.10 mm and mesh 2-
4.700 mm).
The all kinds of ash particles,
especially in the area of small
particles, have a relatively big
surface area, porous surface,
and for this reason they could
have a huge absorptions
capacity.
Two different feedstocks
were used to produce the
biochars used in this
report: rice husks and
bamboo. each material
was generated at different
temperatures.
The rice husks from the
International Rice
Research Institute (IRRI)
- 400ºC, rice husk biochar
from the Asahi Company
- 500ºC.
Bamboo Biochar from
the Industrial Technology
Research Institute (ITRI)
- 300ºC and 600ºC.
All biochars were
obtained by pyrolysis.

51
For the plant growth test,
one pot was used for each
of the binary mixtures. In
total, seven pots were used
for each one of the four
treatments for the three
different locations
Each biochar was mixed
separately with soil and
bottom ash. Trays were
filled with either soil or
soil-biochar-bottom ash
mixtures, randomly placed
on net house benches and
watered before sowing the
seeds.
Prior to planting in pots, a
germination test was
performed. Thirty maize
seeds (Zea mays L.) were
sown into germination trays
using one tray for each of
the different test
Teatments (M1+F=Mesh 1 with
fertilizer, M1/wF=Mesh 1
without fertilizer, M2+F=Mesh 2
with fertilizer and M2/wF= Mesh
2 without fertilizer).
Trays were watered daily.
Germination percentages were
recorded between days 5 and 10
after sowing.
(M1WF=Mesh 1 with fertilizer,
M1NF=Mesh 1 without fertilizer,
M2WF=Mesh 2 with fertilizer
and M2NF=Mesh 2 without
fertilizer).
Pots were prepared and seeds
were sown at a depth of 2 cm
Water was applied after sowing
the seeds. Fertilizer (N-P-K) was
added 2 days after germination
Data are presented only for the
7th day of sowing corresponding
to peak germination.
Plants were harvested after one
month and washed with DI water.
Excess water was removed and
the total fresh weight was
measured.

Material Quantity (g)
Soil 100% 474.0
Soil 50% 237.0
Bottom ash (19.10 mesh) - 100% 518.0
Bottom ash (19.10 mesh) - 25% 129.5
Bottom ash (4.700 mesh) - 100% 497.0
Bottom ash (4.700 mesh) - 25% 124.25
Bamboo 300 - 100% 154.0
Bamboo 300 - 25% 38.5
Bamboo 600 - 100% 16.01
Bamboo 600 - 25% 40.5
RH 400 - 100% 129.0
RH 400 - 25% 32.25
RH 500 - 100% 45.0
RH 500 - 25% 11.25
Pot size 142.70 cm3
52
Heavy metal analysis (ICP) was carried out
to identify the properties of the different
bottom ashes and biochar used.
We examined the effect and the interaction
of rice husk biochar, bamboo biochar and
MSWI bottom ash on the germination and
growth of maize plants.
Accumulation of trace elements in plant
tissue was measured using Atomic-
Absorption Spectroscopy (AA).

53
The first aim of our research is to determine whether adding biochar to soil has an effect on seed
germination. The following results have been seen in previous experiments for rice husk biochar applications:
a) increased the soil pH, thus increasing phosphorus (P),
b) enhanced aeration in the crop root zone
c) enhanced the water-holding capacity of the soil and d)
improved exchangeable potassium (K) and magnesium
(Mg) levels (FFTC, 2001).
It has been found that when incorporated with sludge composting, bamboo biochar is an effective fertilizer
reducing nitrogen loss in the soil (Hua et al., 2009).
The positive outcome was linked to the high adsorption capacity of biochar particles during the composting process
(Dias et al., 2007).
In similar research, Asada et al., (2002) found that bamboo biochar is effective in absorbing ammonia in
soils.
This was attributed to acidic functional groups being formed as an effect of thermolysis of cellulose and lignin at
temperatures of 400 and 500°C (Lehmann and Joseph, 2007).

Our preliminary results in plant
germination showed that
application into the soil of rice
husk biochar and bamboo biochar
in combination with MSWI
bottom ash without fertilizer
differs slightly from the mixtures
where fertilizer was used
This suggests that the application
of fertilizer to the binary mixture
did not cause any impact in the
germination of Zea mays L. seeds.
This effect was attributed to the
high content of beneficial nutrients
already present in bottom ashes
and possibly to the efficient
absorption of heavy metals.
While the use of two different
meshes used for the bottom ash in
this experiment (19.10 (Mesh 1)
and 4.700 (Mesh 2)) did not have
any influence on the germination
results
From the three different cities, the
bottom ash binary mixture with
the most consistent results was the
one source in Pingtung City. Rice
husk biochar (400ºC) presented the
highest germination percentage
(100%) in all treatments
54

56
Plant total weight (kg) Treatments
1 2 3 4 5 6 7
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
Plant weight
Pingtung BA-M1WF
0.025
0.034
0.024
0.029
0.031
0.013
Soil BA+S BA+
RH400
BA+
RH500
BA+
B300
BA+
B600
BA
a)
Plant weight
Pingtung BA-M1NF
1 2 3 4 5 6 7
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
Plant total weight (kg)
Treatments
0.009
0.011
0.027
0.021
0.023 0.024
0.011
Soil BA+S BA+
RH400
BA+
RH500
BA+
B300
BA+
B600
BA
b)
Plant weight
Pingtung BA-M1WF
1 2 3 4 5 6 7
c)
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.011
Treatments
0.021
0.009
0.029
0.022 0.021
0.009
Soil BA+S BA+
RH400
BA+
RH500
BA+
B300
BA+
B600
0.040
0.035
0.030
0.025
0.020
0.015
0.010
0.005
0.000
0.012
Plant weight
Pingtung BA-M2NF
BA 1 2 3 4 5 6 7
Treatments
0.013 0.014
0.027
0.018
0.010
0.014
Soil BA+S BA+
RH400
BA+
RH500
BA+
B300
BA+
B600
BA
d)
Pingtung BA‐M1WF = Pingtung bottom ash mesh 1 with fertilizer, b) Pingtung BA‐M1NF= Pingtung bottom ash mesh 1
without fertilizer, c) Pingtung BA‐M2WF= Pingtung bottom ash mesh 2 with fertilizer, d) Pingtung BA‐M2NF = Pingtung
bottom ash mesh 2 without fertilizer. Error bars show standard deviation of data.
Pingtung bottom
ash (mesh 1 and 2,
with and without
fertilizer) biomass
total weight.
Figures b, c and d
showing the best results
in the application of
the biochar-MSWI
bottom ash binary
mixture
Were rice husk biochar
(400 ºC) showed the
highest weight in
treatments with exception
of “a”, were Pingtung
BA-M1WF treatment
BA+S (bottom ash with
soil) showed the higher
total weight.

57
To determine the total heavy
metal content of the samples,
bottom ash leaching samples
were analyzed using inductively
coupled plasma atomic
emission spectroscopy (ICP-AES
The contents determined by
ICP showed that the different
biochars had important element
content that is beneficial for
plant development.
The contents determined by
ICP showed that bottom ash
from the three different cities
did not differ from each other
in most of the elements.
There were differences in only
four elements: Ca > Pb > Na >
Fe.
Calcium constituted the largest
proportion of the elements
present in the bottom ash with
a high difference in the content
between in Pingtung and
Chiayi BA, and showing
similar content between Chiayi
and Changhua BA.
The pH of the bottom ash,
when mixed with water, was as
follows: Pingtung = 4.92,
Chiayi = 6.63 and Changhua =
6.59. There was not a high
reduction in pH leaching of
metals.

58
The bioaccumulations in tissue of Sr and Cu were higher than lead (Pb) contents in biomass
tissue. Cooper (Cu) concentration was the highest in plants tissue with P1 F + BA + RH 500
(219.607 mg/L) followed by the use of P2 NF + BA + BAMBOO 300 (23.999 mg/L) and the
use of P2 NF + BA + SOIL (24.446 mg/L) .
According to Hong et al. (2008), bioaccumulation of elements in different
parts of the plants varies both with the concentration of the elements and the
type of vegetable.
In this research, the bioaccumulation of elements in plan tissue was found in
concentrations not permitted for food products according to Hong Kong
Government Center for food safety (2011).
Special attention should be placed into the bioaccumulation of Cu, since it
was the heavy metal that accumulated in higher concentration.

Treatments Pb(mg/L) Cu(mg/L) Sr(mg/L)
P1 F + BA 4.064 0.06 3.506
P1 F + BA + BAMBOO 300 ND 0.56 3.637
P1 F + BA + BAMBOO 600 ND 0.096 4.244
P1 F + BA + RH 500 ND 219.607 5.083
P1 F + BA + RH 400 ND 3.717 3.243
P1 F + BA + SOIL 4.203 6.308 3.167
P1 NF + BA 7.375 0.624 5.56
P1 NF + BA + BAMBOO 300 ND 0.457 2.98
P1 NF + BA + BAMBOO 600 ND 1.78 2.674
P1 NF + BA + RH 500 ND 3.594 3.663
P1 NF + BA + RH 400 3.875 0.131 3.385
P1 NF + BA + SOIL ND 0.424 3.192
P1 NF + SOIL ND 3.962 2.643
P2 F + BA 4.569 5.311 5.12
P2 F + BA + BAMBOO 300 0.075 1.611 3.055
P2 F + BA + RH 500 4.121 1.267 2.974
P2 F + BA + RH 400 ND 1.969 2.824
P2 F + BA + SOIL 0.67 2.159 2.746
P2 F + BA +BAMBOO 600 1.378 0.947 3.365
P2 F + SOIL ND 2.059 2.431
P2 NF + BA + BAMBOO 300 4.187 23.999 2.763
P2 NF + BA + BAMBOO 600 ND 0.22 3.594
P2 NF + BA + RH 500 ND 2.173 2.789
P2 NF + BA + RH 400 2.253 2.237 2.498
P2 NF + BA + SOIL ND 24.446 3.018
P2 NF + SOIL ND 2.733 3.627
59
Table 4.5, shows results of Pb, Cu, and
Sr analyzed for Pingtung bottom ash,
due to its high plant growth on
treatments
P1= Pingtung mesh 1(19.10 m/m-)
P2= Pingtung mesh 2 (4.700 m/m-), F=
With addition of fertilizer
NF= No fertilizer was used,
BA= Bottom ash, RH 400
IRRI = Rice husk biochar pyrolyzed at
400°C
RH 500 Company= Rice husk biochar
pyrolyzed at 500°C
Bamboo 300 = Bamboo biochar
pyrolyzed at 300°C
Bamboo 600 = Bamboo biochar
pyrolyzed at 600°C.

60
ICP of Biochars
RH
RH
400
500
Bambo
o 300
Bambo
o 600
Elements mg/L
Fe 77.4 3.36 0.462 1.02
Zn 5.07
0.64
5 0.569 0.97
Na NA 17.8 5.65 5.62
K 62.2 159 82 103.0
Ca 18.2 39.4 7.9 13.0
Mn 4.65 6.94 1.67 2.62
Mg 23 17.9 13.4 22.2
Cu
0.15
4
0.15
7 0.101 0.293
Elements Pingtung Chiayi Changhua
mg/L
Fe 285.3
Al 54.3
Si 74.7 48.5 38.6
Pb 317.0 0.0 0.1
Zn 107.3 6.7 39.4
Cd 0.0
Ni 0.7 0.2 0.3
Cr 0.9 0.0
Na 69.5 290.0 173.3
K 18.9 109.5 65.8
Sb 1.6 0.2 0.2
Ca 1099.0 2392.0 2481.0
Mn 11.6 3.2 3.1
Mg 30.2 49.9 47.7
Sr 3.5 6.2 5.9
Ba 0.5 0.6 0.5
Cu 2.0 2.5 4.1

63
To demonstrate that rice husk biochar could act as a soil
conditioner, enhancing water spinach growth by supplying and
retaining nutrients and thus improving the soil’s physical and
biological properties.
To explore whether rice husk biochar (RHB) and wood biochar
(WB), in combination with fertilizers, could increase the biomass
yield of water spinach.
We hope that the results of our work may help to determine
which of the biochars is more beneficial in boosting the production
of water spinach.

Production of rice husk
biochar (RHB) was
carried out by the
Industrial Technology
Research Institute (ITRI),
located in Hsinchu,
Taiwan.
RHB was pyrolized using
a small-scale reactor at
300-350ºC with a
residence time of 1 hour.
These temperatures may
be applicable for small
scale farmers who lack
access to credit and
cannot afford high-scale
pyrolysis plants.
66
In a study made by
Hossain et al. (2011)
concerning the influence
of pyrolysis temperature
on production and the
nutrient properties of
biochar, researchers
concluded that pyrolysis
temperature has a
significant effect on the
chemical properties of the
biochar produced.
Wood biochar (WB) was
purchased in an
agricultural shop near the
experimental site and WB
was prepared by open-burn
(the proposed
temperature was 250-300
ºC).
In order to observe the
performance of both
biochars in their original
shapes, we avoided the
use of grinders or sieves
to reduce the particle size
in the soil applications.

67
By using an SEM S-3000N
HITACHI production
microscope, the
morphology of both WB
and RHB samples was
examined
A Perkins-Elmer EA
analyzer determined the
elemental composition of
the biochar, such as the
biomass that would be ideal
for application as biochar
for carbon sequestration.
A Bruker Vector-22 FT-IR
spectrometer identified the
sample to determine the
organic functional groups
present for each biomass,
especially carbons.
Volatile matter in biochar
was determined following
the ASTM D 3175 -07
standard test method.
A Beckman Coulter SA
3100 BET analyzer
containing approximately
0.1000 g to 0.2000 g of
each biochar sample was
then used at a temperature
of 50Cº for 60 to determine
the surface area of each
biochar.
Electrical conductivity and
total dissolved solids were
measured using a SUNTEX
SC-110 portable
conductivity-meter.
The trace metals analysis in
the samples was realized by
using a Perkin-Elmer 3000-
XL inductively coupled
plasma (ICP-AES)
spectrometer.

Field trial
The experiment was
carried out between
December 2010 and
February 2011 on the
campus of National
Pingtung University
of Science and
Technology (22°38'N,
120°36'E) in Pingtung
County in the
southern part of
Taiwan.
Soil analysis
Soil was sampled
from a 0 to 20 cm
horizon on a clayey
Ultisol, which is
typically used for
vegetable and fruit
production in
southern Taiwan.
68

Water spinach plants were
germinated for two weeks and
later transplanted into plots.
Each plot was 1.94 m x 1.10 m.
Five different treatments were
assigned to each of the biochars
and to one control group.
RHB and WB were weighted
and added to each plot. Every
plot was mixed with the assigned
quantity of biochar using the
“top soil” mixing technique
(Major, 2009).
The effect of biochar on root
growth was measured to
compare the effects of the
different types and quantities of
rice husk and wood biochars
used.
After eight weeks of growth, the
plants were harvested. Plant
morphological characteristics
measured included: leaf number,
leaf length, leaf width, stem
number, stem size, fresh plant
weight, root growth and the
chlorophyll content of the leaves
Before transplanting, each plot
was irrigated for 20 min. Plants
were transplanted 15 cm apart,
with 22 plants per plot. A
perforated pipe system was used
to water the plants every 2 days
for 10 min. Soluble N-P-K
fertilizer 20-20-20 was applied to
the crops
Relative chlorophyll content
(Soil Plant Analysis
Development (SPAD)) was
measured every two days using a
Minolta chlorophyll meter
(model SPAD 502).
69

70
There were eleven
treatments for rice husk
biochar and wood biochar,
along with one control
group.
Four soil samples from
each treatment were dried
in a precision oven at
35ºC, homogenously
mixed, ground and passed
through a 2mm sieve.
A 20:20 (soil: distilled
water) solution ration was
prepared for the
determination of pH.
Organic carbon (OC) and
organic matter (OM) were
determined using the
Walkley-Black method
(Walkley and Black,
1934).
Soil texture and
characteristics were also
obtained using the
hydrometer method
(Milford, 1997).

71
The SEM-EDX
analysis showed that
the microstructure of
the rice husk biochar
was highly
heterogeneous
Rice husk biochar
particles consisted
of higher silicon
(Si) mineral
agglomerates on
lower carbon
content fibers with
structures typical of
its biomass origin.
They exhibited a
large degree of
macro-porosity in
the 1 to 10 micron
scale, with contents
of carbon (C),
oxygen (O) and
potassium (K).
On the other
hand, SEM-EDX
analysis for WB
indicated that the
biochar particles
consisted of high
potassium, and
calcium mineral
agglomerates.

Elements evaluated Fresh rice husk Rice husk
biochar
Wood
biochar
Characteristics of materials
T (⁰C) - 300 - 350 -
Si (mg/kg) 107 171 10
Ca (mg/kg) 108 220 273
K (mg/kg) 9523 175 305
Mg (mg/kg) 175 182 72.23
Water (%) 11.3 3.9 -
Ash (%) 12.63 50.53 -
pH (%) 6.41 8.02 7.32
Elemental
analysis
Fixed C (mg) - 43.73 52.74
H (mg) - 2.38 3.58
N (mg) - 1.0 0.72
S (mg) - 0.19 0.37
O (mg) - 2.36 -
VM
Volatile
Matter (%)
2.42 1.86 1.70
BET
Surface Area Analysis
(m²)
- 2.21 37.95
Salinity
EC (μs/cm) 1220 1392 704
TDS (ppm) 488 558 282
Sal (ppt) 0.2 0.2 0.1
Heavy metal analysis
Fe (mg/L) - 8.72 0.1
Al (mg/L) - 0.97 0.37
Cu (mg/L) - 0.09 0.01
Pb (mg/L) - - -
Zn (mg/L) - 0.7 0.4
Cd (mg/L) - - -
Ni (mg/L) - 0.11 -
Cr (mg/L) - 0.03 -
Na (mg/L) - 7.49 23.9
Sb (mg/L) - - -
72
Results from several
analyses, including: EA,
BET surface area, EC,
TDS, and ICP heavy
metal analysis, revealed
the applicability of rice
husk and wood biochars
on soil.
Results from EA tests show
a high percentage of carbon
in wood biochar.
According Stoylle (2011), a
high percentage of carbon
means the biochar can
absorb more atmospheric C
from the environment.
Rice husk had a higher
VM content as
compared to rice husk
and wood biochars.
In comparison with rice
husk, wood exhibits a
larger BET surface
Rice husk biochar has a area/m².
significantly higher EC
value than wood
biochar, meaning
greater quantities of
dissolvable ions are
present in rice husk
biochar than in wood
(Basile-Doelsch et al.,
2007).
Concentrations of heavy
metals in the tested
biochars were all far
below the ICP detection
limits. Major differences
between wood and rice
biochar were in the
content of Sodium (Na)
and Manganese (Mn).

As indicated in Figure “a”, the WB added to soil increased the plant weight of water spinach by
increasing the root size and leaf width; while the RHB added soil increased the plant weight of
water spinach by increasing the stem size and leaf length as seen in figure “b”.
73
(a) The relations between root size and leaf wide and plant weight of WB and figure 5.5 (b), relations between
stem size and leaf length and plant weight of RHB added plant samples.

In Figure “a”, the stem size of water spinach is shown to be proportional to the
WHC/silt ratio, while the root size of water spinach is proportional to the OM/OC
74
ratio, as shown in Figure “b”.
(a) The relations between and WHC/silt ratio and stem size of RHB and WB added plant samples and figure 5.6 (b) relations between and
OM/OC ratio and root size of RHB and WB added plant samples.

Based on the changes in the silt and sand content in soil described in the figures, we can conclude that
the decomposition of OC in biochar to soil OM resulting in the increase in WHC and the decreasing in
silt is the mechanism of WB and RHB application.
The stability of biochar is affected by pre-existing soil OM; the results indicate that the decomposition
reaction of WB biochar is faster than that of RHB under a lower dosage amount (< 1.5 kgm3), while this
reaction is inversed with an increased dosage ( > 3.0 kgm3).
75
(a) Changes of sand and silt content in the WB added soil and figure 5.7 (b) changes of sand and silt content in the RHB added soil.

78
To assess the potential effects biochar from rice husks pyrolized on Corn
(Zea mays L.) seeds germination and plant growth.
 To observe how the silicon content rice husk biochar could affect the
development of the crop.

79
Rice-husk biochar has high silica (SiO2) contents and silicon (Si) is a beneficial element for
plant growth that helps plants overcome multiple stresses including biotic and abiotic stresses.
Silicon is effective in preventing rice lodging by increasing culm wall thickness and vascular
bundle size (Shimoyama, 1958), thereby enhancing stem strength.
Silicon plays an important role in increasing plant resistance to pathogens such as blast on rice
(Datnoff et al., 1997) and powdery mildew on cucumbers (Miyake and Takahashi 1982).
However, agronomists and farmers are not always aware that they could be able to improve
crop production with increased stress and disease resistance by adding up a source of available
silicon to the soil.
Reports on the Si effect of rice husk biochar on plant seed germination are scant.

Four rice husk biochars were used
in this study IRRI
ITRI biochar was prepared by the
Industrial Technology Research
Institute in a specialized biochar
reactor
Several analyses including
scanning electron microscopy
(SEM),X-ray spectroscopy
(EDX), Fourier transform
infrared spectroscopy (FT-IR),
volatile matter (VM), electrical
conductivity (EC), water
holding capacity (WHC), and
heavy metal analysis (ICP), were
used to characterize the biochars
properties.
NPUST
Shui-known

81
Treatment Percentage of combined
materials
pH of
material
s
Pyrolysis
Temperature
IRRI-B 50% Soil+50% biochar 7.38 400Ԩ
ITRI-B 50%Soil+50% biochar 8.02 500Ԩ
NPUST-B 50%Soil+50% biochar 8.53 350Ԩ
SK-B 50%Soil+50% biochar 10.04 700Ԩ
DRH 50%Soil+50% rice husk 5.76 25Ԩ
SOIL No soil amendment
(control)
5.02 -
SOIL-F Soil + fertilizer 6.00 -
IRRI‐B = International rice research institute biochar, ITRI‐B = industrial technology
research institute biochar, NPUST‐B = national pingtung university of science and
technology biochar, SK‐B = shui‐known company biochar, DRH = dried rice husk,
SOIL‐B = soil plus fertilizer.

82
These seven treatments were
arranged in fully randomized
design with 4 replications, each
one of 10 plants in separated
pots
The amount of soil amendment
applied (45g) was calculated
based on the surface area of the
plastic pot used ( 4.5 x 5.0 cm).
The amendments were mixed to
a 5 cm depth, after preparation
they were placed in the net
house and watered every two
days.
10 plants (pots) were grouped
together to make one plot for a
total of 7 treatments x 4
replications x 10 plants
(pots)/plot = total of 280 plants
(or pots).
The germination and growth of
corn plants was performed for
15 days.
The plants were harvested at the
end of the growth period and
kept under refrigeration to
further analysis.
X-ray (EDX) was used to
examine the morphology and
silicon content of dried rice
husk and biochar rice husk
samples.
FT-IR was used for the
identification of the organic
functional groups present for
each biomass, especially carbons
and -OH- groups.
Differences between biochar
treatments were analyzed by one
way ANOVA using Duncan and
LSD tests for means
comparisons where ANOVA
showed significant differences
between treatments.

83
The germination percentage for corn from the seven
different treatments can be observed in figure
6.1(a). Germination started on the 3rd day after
seeds were planted.
Plants growth with biochar showed good
development after germination. The
treatment that showed the best germination
was ITRI-B, which is a biochar produced
by the Industrial Technology Research
Institute (ITRI)
Has a pH of 8.02 and was
prepared at a temperature of
500Ԩ, unlike treatments with
biochar additions from IRRI
and SK, these treatments
showed an inhibition in seeds
germination
Saeed A. Abro et al., in 2009, assessed
the effects of different levels of Silicic
acid on germination of wheat seeds,
where 7.2g silicic acid Kg-1 was applied
to treatments and decreased considerably
the germination of wheat seeds, this
shows that increased levels of silicic acid
reduces the germination rate.

Stem size mean for corn from the seven different treatments can be
observed in figure 6.1(e). The treatment that showed the highest stem mean
was SK-B, has a pH.
Root development (figure 6.1f) was found to be significantly affected by the
use of rice husk biochars in plants in comparison with soil and soil with
fertilizer treatments
According to the Anova mean comparison (figure 6.1g), the rice husks
biochar treatments showed significantly higher weight than the rest of the
biochars and soil treatments on biomass growth were NPUST-B and ITRI-B.
Studies realized around the world, have shown that applying supplemental
silicon can inhibit plant disease, decrease insect pests injuries, and improve
crop tolerance to environmental stress (Heckman, 2012).
In a similar research made by Sundahri et al., (2001) were found positive 84
effects of gypsum and sodium silicate on the wheat grown under
waterlogged soils especially in increasing plant height leaf and shoot dry
mass.

85
(d)
(e)
Scanning electron micrographs and EDX spectrograms of element particles found in raw rice husk and rice husk biochar from pyrolysis process at
different temperatures: (a) in IRRI biochar, (b) in ITRI biochar, (c) in NPUST biochar, (d) in SK biochar and (e) in dry rice husk.

86
Germination Mean
Silicon Weight (%)
29.84%
8.75
24.38%
4.75
26.86%
9.0
1.06%
10.0
35.24%
1 2 3 4 5
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
0 2 4 6 8
5.0
IRRI-B ITRI-B NPUST-B SK-B DRH
Seeds germinated (mean)
and Si weight percentage
Treatments with biochar
IRRI‐B = International rice research institute biochar,
ITRI‐B = industrial technology research institute biochar,
NPUST‐B = national pingtung university of science and
technology biochar, SK‐B = shui‐known company
biochar, DRH = dried rice husk.
Relationship between germination mean versus Si
content for the tested rice husk biochars.

87
The results detailing the growth of water spinach
showed that the application of rice husk biochar
improves biomass production, increased plant
weight by increasing the stem size and leaf length
of the water spinach.
In addition, the stem size of water spinach was
proportional to the WHC/silt ratio; whereas the
root size of water spinach was proportional to the
OM/OC ratio of soil.
We also proposed that the working mechanism of
RHB in soil would be such, that the decomposition
of OC in biochar-added soil to OM resulted in
increased WHC and decreased silt in biochar-added
soil (Milla et al., 2013).

90
 To show that bamboo wood is a smart option for those industries that
want to transform biochar into a profit without harming any
ecosystem.
 To investigate the potential capability of bamboo biochar to affect
germination and growth of edible crops.
 To demonstrate the effects on germination of different temperatures
(240oC, 300oC, 600oC and 700oC) of bamboo biochars used in this
study.

91
Bamboo charcoal may be an ideal amendment for nutrient conservation
and heavy metal stabilization due to its excellent adsorption capability.
Recent research found that biochar could act as soil fertilizers or
conditioners to increase crop yield and plant growth by supplying and
retaining nutrients (Glaser et al., 2000; Major et al., 2005; Steiner et al.,
2007).
Bamboo biochar has been used in studies where the content of polyphenols
released by the carbon matrix was measured, as well has been tested is
combination with the same type of bottom ash as agronomic materials
(Milla and Huang, 2013 & Milla, Wang and Huang, 2013).
However, there has been no research to date on the effects of pyrolyzation
temperatures of bamboo biochar in seed germination and plant growth.
In this study we present the results of a germination test and growth
parameters made with four different biochars, produced under different
pyrolysis temperatures (240, 300, 600 and 700ºC) and evaluated at two
rates of applications (1- 100 (10%) t/ha, calculated as soil volume to 10 cm
soil depth, and 2- pure biochar without soil application).

Biochar made from bamboo
was used to produce the
biochars applied in this test.
Bamboo biochar was
generated at different
temperatures: 240, 300, 600
and 700ºC.
All biochars were obtained
by pyrolysis with a
temperature raising rate of
5oC/min; biochars were
sieved using a 4 mm sieve
before use for the bioassays.
Characterization of the
material was made applying
various test and analyses.
X-ray diffraction (XRD)
analysis was carried out to
identify any crystallographic
structure in the four biochar
samples
Fourier Transform Infrared
spectroscopy analysis (FT-IR)
was used for the
identification or fingerprint
of a sample or solution to
determine the organic
functional groups.
Heavy metal analysis (ICP)
was carried out to identify
the properties of the biochar
used.
A HITACHI S-3000N
scanning electron microscope
equipped an energy dispersion
X-ray (EDX) was used to
examine the morphology of the
biochar samples.
Volatile matter in biochar
was determined following
the ASTM D 3175 -07
standard test method
(ASTM, 2004).
Water holding capacity
(WHC) of biochars was
measured regarding the
following procedures of soil
analysis manual (Lee,
2007).
Electrical conductivity, total
dissolved solids and pH
were measured using a
SUNTEX SC-110 portable
conductivity-meter.
92

Two different crops were
evaluated, (glutinous corn and
Chinese cabbage) addition of
biochar at 100% (pure biochar
without soil – test 1) and 50%
biochar (50-50 soil-biochar relation
– test 2) were evaluated.
Seedbeds where prepared in order
to test the four different
temperatures of bamboo biochars.
Each treatment had 16 pots.
Seeds were sown in 500 mL soil in
a plastic container (16 cm × 10 .5
cm × 5 cm), the data of
germination rate, started to be
quantified on the 3rd day followed
by measures on the 5th and 7th
day of the trial.
For corn a single seed was placed
into the germination pots unlike
cabbage, where 2-3 seeds where
placed, due to their difference in
sizes.
Stem size, leaf number, leaf width
and leaf length of each one of the
emerged plants for corn and
cabbage was measured.
Statistical analysis of variance
(ANOVA) was performed using
SAS (v.9.2)
93

ICP of Biochars
Elements
mg/L
Raw
Bamboo 240 °C 300 °C 600 °C 700 °C
Fe 4.2 18.5 0.5 1.0 1.0
Zn 0.3 0.3 0.6 1.0 0.9
Na 6.4 6.0 5.7 5.6 12.7
K 59.9 62.6 82.0 103.0 131.0
Ca 8.6 8.5 7.9 13.0 12.3
Mn 0.4 0.5 1.7 2.6 2.7
Mg 19.9 7.1 13.1 22.2 18.8
Cu 1.0 0.1 0.1 0.3 0.2
WHC % 78.0 85.0 97.0 150.0 200.0
VM % 3.7 3.0 2.8 1.0 1.0
94
The contents
determined by ICP
showed that as
pyrolysis temperature
increased the presence
of elements in their
majority also increased
(Na, K, Ca, Mn, Mg).
Raw bamboo has a
percentage water holding
capacity of 78.0% that is
enhanced by
carbonization process,
resulting in 200% water
retention.
In our study, water
holding capacity
(WHC) increased to
a maximum value as
pyrolyzation
temperature
increased.

1.0
0.9
0.8
0.7
0.6
(a)
(c)
(b)
(d)
(e)
Amine
CO2
-CH3
Aromatic
C-O
-CH C=O 2-
-OH
4000 3500 3000 2500 2000 1500 1000 500
Intencity (%)
Wave number(cm-1)
95
FTIR Spectra of tested samples, each letter (a,b,c,d,e)
represents raw bamboo biomass and different pyrolysis
temperature: (a) 240oC, (b) 300oC, (c) 600oC, and (d) 700oC.
In this analysis of
biochar, the FTIR was
used specifically to
determine the functional
groups present for each
temperature and
biomass, especially
carbons and aromatics.
Various bonds in the spectra (at 3412.49 ~
3469.91 cm−1) corresponds to -OH stretching
vibrations and this may be caused by acid
and/or alcohol structures.
The results of FT-IR and
elemental analysis shows
regardless of the
similarity in temperatures
in some biochars, the
intensity and the
concentration of the
surface functional groups
would vary.
All of the samples also
have a C≡N bonding in
the same position of
the CO2 peak (2347.92
cm−1), this is expected
due to the possible
presence of nitrogen in
the biochar.
The importance of these
differences from a soil
fertility point of view is
that surface area and
porosity of the biochar
plays a significant role
in soil fertility.
In contrast to the optimum
conditions for the formation of the
acid functional groups, more intense
charring conditions (higher
temperatures and longer charring
times) are required for the formation
of porosity and surface area in the
biochar (Rutherford et al., 2004).

96
a - Raw bamboo
b - Bamboo 240 0C
c - Bamboo 300 0C
d - Bamboo 600 0C
e - Bamboo 700 0C
Cellulose Intensity (a. u.)
(a)
(b)
(c)
(d)
(e)
Graphite crystal
101
100
002
10 20 30 40 50 60 70 80
2 Theta (degree)
X‐ ray diffraction patterns of biochar samples; each letter (a, b, c, d, and e)
represents raw bamboo biomass and different pyrolysis temperature: (a)
240oC, (b) 300oC, (c) 600oC, and (d) 700oC.

97
SEM–EDX analysis of biochar (a, b, c, d). The formation of particle size is showed for the
four temperatures applied to obtain biochar. Is observed how porosity is developed,
higher temperatures – the porosity number increases and the size of the pores narrows
down, giving as a result better water holding capacity.
The formation of
particle size is showed
for the four
temperatures applied to
obtain biochar. Is
observed how porosity
is developed, higher
temperatures – the
porosity number
increases and the size
of the pores narrows
down, giving as a result
better water holding
capacity.
If the development of
pores in biochar
samples is enhanced
with increasing
temperature (especially
at 600 and 800oC), it
may result in
significant
improvement in the
pore properties of
biochars (Mohammad
et al., 2013).

98
a a a a a
a
1 2 3 4
1 2 3 4
110
100
90
80
70
60
50
40
30
b
a
b
ab
a
ab
b
a
1 2 3 4 1 2 3 4 1 2 3 4
Seed germination mean (%)
Biochar treatments
Pyrolysis temperatures
1) 240 0C
2) 300 0C
3) 600 0C
4) 700 0C
Corn 50% Cabbage 50% Corn 100% Cabbage 100%
(a)
Effects of different temperatures and rates of bamboo biochar applied for corn and cabbage.
(a) Seed germination percentage, (b) stem size (cm), and (c) leaf number were tested at rates
of 50 and 100%. Error bars show standard errors of the mean. Mean data followed by a similar
letter are not statistically significant within each biochar temperature.
100% - 600oC 100% - 700oC
50%-700oC

Preparation and Plant-growth Efficiency Assessment of Biochars

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