This document discusses a study on the integrated effects of biochar and PK fertilizer on maize yield and soil properties in Pakistan. The main objectives were to assess how biochar alone and combined with PK fertilizer affects maize yield, nutrient uptake, and soil properties like bulk density, soil organic matter and total nitrogen. A literature review found that previous studies show biochar can increase crop yields even without nitrogen fertilizer by improving soil quality. When combined with fertilizer, biochar led to even greater yield increases. The review also found that applying phosphorus at 100kg/ha resulted in maximum maize growth and yield.

1. 1
INTEGRATED EFFECT OF BIOCHAR AND PK FERTILIZER ON MAIZE YIELD
AND SOIL PEROPERTIES
INTRODUCTION
Maize is an important summer cereal crop grown in Pakistan. At national level during
2008- 2009 the total area under maize cultivation was 1051.7 thousand hectares with a total
production of 3604.7 thousand tons and average grain yield of 3427 kg per hectare. The figures
in Khyber Pakhtunkhwaare 509 thousand hectares with a total production of 903.9 thousand tons
and average yield of 1776 kg hectare-1 (MINFAL, 2006). Maize is multipurpose cereal crop that
provides food for human, feed for animals, and raw material for the industries (Khaliq et al.,
2004).
In developing countries, maize is consumed directly and serves as staple diet for about
200 million people. However, in processed form it is used as fuel (ethanol) and starch. Starch in
turn involves enzymatic conversion into products such as sorbitol, dextrine, sorbic and lactic
acid, and appears in household items such as beer, ice cream, syrup, shoe polish, glue, fireworks,
ink, batteries, mustard, cosmetics, aspirin and paint (Plessis, 2003).Maize is one of the most
important sources of edible oil. Our country spends a huge amount of foreign exchange every
year to import edible oil. Starch is the main product of maize for which dextrin, liquid glucose,
solid glucose, powder glucose and crystalline dextrose are prepared (Masood et al., 2011).
Maize is an exhaustive crop having higher potential than other cereals crops to consume
large quantity of nutrients from the soil during growth (Chen et al., 1994). Intensive cultivation,
growing of exhaustive crops, use of imbalanced and inadequate fertilizers accompanied by
restricted use of organic manures have made the soils not only deficient in the nutrients, but also

2. 2
deteriorated the soil health, productivity is largely dependent on nutrient management. Maize
needs fertile soil to express its yield potential. Additions of organic manure not only supply the
plant nutrients but also improve soil health (Kannan et al., 2013).The reduction of maize yields is
a result of reduced fertilizer application and nitrogen use efficiency. Degraded soils have reduced
mineral availability as a result of reduced cation exchange capacity. These soils have low pH
levels and as a result large amount of nutrient loss especially nitrogen through leaching. The soils
are generally becoming sandy with reduced organic matter content (Cushion et al., 2010)
Biochar is a fine-grained, carbon-rich, porous product remaining after plant biomass has
been subjected to thermo-chemical conversion process (pyrolysis) at low temperatures (350–
600°C) in an environment with little or no oxygen (Amonette and Joseph, 2009). Biochar is
composedof, sulphur (S), hydrogen (H), nitrogen (N), oxygen (O), carbon (C)and ash in different
proportions (Masek, 2009). The important quality of biochar that makes it attractive as a soil
amendment is its highly porous structure; potentially responsible for improved water retention
and increased soil surface area (Arias et al., 2008). Biochar addition to agricultural soils can
improve soil fertility, with the added bonus of climate change mitigation through carbon
sequestration (Cornelissen et al.,2013). Conversion of biomass into biochar stabilizes the carbon
(C) that is then applied to soil; diminish increased levels of CO2 in the atmosphere. Biochar
contains high concentrations of carbon that is recalcitrant to decomposition, so it may stably
sequester carbon (Glaseret et al., 2002). Biochar amendments alter soil physical properties
(Venterea, 2008). Addition ofbiochar to soils improves soil fertility and thus increase crop yield
of agricultural lands (Marris, 2006; Chan et al., 2007). Application of biochar has beneficial
effects on soil properties like increased water holding capacity, enhanced cation-exchange
capacity (CEC), higher pH, increased water retention, reduced leaching of nutrients and adding

3. 3
nutrients by itself (Lehman & Joseph, 2009).Biochar application increases crop yields of maize
(Kimetu et al., 2008).Biocharhas the potential to improve soil quality, crop yield and to expand
terrestrial soil carbon pool (Palumbo et al., 2009). Biochar added in the soil can increase
microbial activities (Pietikainenet al., 2000). Biochar application to soil helps in several ways:
less fertilizer is needed because biochar absorbs and slowly releases nutrients to plants,biochar
improves soil moisture retention and conserves water, securing the crops against drought and
reduces the methane emissions from paddy. It increases the soil microbes and decreases the bulk
density of soils. It supports better growth of roots and helps in reclamation of degraded soils
(Cushion et al., 2010).
Phosphorus is one of the most important nutrients for higher yield in larger quantity
(Chen et al.,1994) and controls mainly the reproductive growth of plant (Wojnowska et al.,
1995). P is the second most crop-limiting nutrient in most soils. It is needed for growth,
utilization of sugar and starch, photosynthesis, nucleus formation and cell division, fat and
albumen formation. Energy from photosynthesis and the metabolism of carbohydrates is stored
in phosphate compounds for later use in growth and reproduction (Ayub et al., 2002). It is
readily translocated within the plants, moving from older to younger tissues as the plant forms
cells and develops roots, stems and leaves (Ali et al., 2002). Adequate P results in rapid growth
and earlier maturity and improves the quality of vegetative growth.It is a fundamental nutrient
for plants, because it plays a vital role in many physiological and biochemical processes
(Mathews et al., 1998). It is a structural component of nucleic acids, many co-enzymes, phospho-
proteins and phospho-lipids (Ozanne, 1980).
Potassium (K) is an essential nutrient for plant growth and cannot be replaced by other
elements. The function of potassium is associated with increased root growth and tolerance to

4. 4
drought, cellulose formation, enzyme activity, photosynthesis, transportation of sugar and starch.
It also increase protein content of plants, maintain turgor, reduce water loss, and to protect plants
against diseases and nematodes (Thomson, 2008). In Pakistan most of soils contain relatively
large amounts of total K, however only a small fraction is present in available form to plants.
Most of the soils have <1 50 mg kg-1 of exchangeableK, which is considered a critical limit for
soil K deficiency (Bajwa and Rehman, 1 996).
The cultivable land is a limited resource and its expansion is not possible, the concern
regarding increased crop production on sustainable basis.There is a dire need of developing new
strategies,integrated use of organic and inorganic fertilizers to the soil, in order to maintain and
protect the current soil resources and to feed the present and future generations. The issue is
directly related to maintain the soil quality, refers to the soil’s capacity to support crop growth
without resulting in soil degradation or harming the environment. This study is therefore
proposed to assess the integrated effect of biochar and PK fertilizers on soil properties and maize
yield in Peshawar valley.

5. 5
OBJECTIVES:
Main objective
1. To assess the integrated effect of biochar and PK fertilizer on yield of maize and soil
quality.
Specific objectives
1. To determine the effect of biochar alone and in combination with PK fertilizer on yield
and yield component of maize.
2. To determine the effect of integrated use of biochar and PK fertlizer on nutrient uptake of
maize.
3. To determine the effect of biochar and PK fertilzer on soil properties (bulk density,
S.O.M and total nitrogen).

6. 6
REVIEW OF LITERATURE
Zhenget al(2010) conducted a field experiment on using biochar as a soil amendment for
sustainable agriculture. Two sources of biochars were used in the field trial. One was pyrolyzed
from corn cobs at 450 oC (biochar-A) and the other produced from wood chips at 450 Co
(biochar-B). The effect of three fertilizer treatments, no fertilizer at 0 lbs N acre-1, 50% fertilizer
application (81 lbs N acre-1), and 100% fertilizer application (192 lbs N acre-1) on corn yields
and concluded that application of biochar as a soil amendment has significantly increased crop
yields, even in the absence of nitrogen fertilizer the corn yields increased approximately 18%
and 23% for biochar-A and biochar-B, respectively, compared to the field without any treatment.
Thestudy showed that the addition of biochar may improve soil quality or release nutrients to
plants. With the application of nitrogen fertilizer, more significant increases in crop yields were
observed in both biochar treatments. When biochar was integrated with fertilizer, the crop yield
increased by approximately 54% and 39% for biochar-A and biochar-B in the 50% fertilizer
treatment respectively, and 72% and 44% in 100% fertilizer use, respectively.The results further
suggested that biochar as soil amendment can efficiently utilize the nutrients by holding
ammonium ions in soils and inhibiting nitrogen fertilizer nitrification.
Masood et al (2011) conducted a field experiment in order to investigate the effect of
different phosphorus levels, 0 (control), 50, 100, 150 and 200 kg ha-1 on the yield and yield
components of maize and concluded that different levels of phosphorus significantly affected
maize plant height, number of cobs plant-1, number of grains cob-1 and grain yield. Application
of P at the rate of 100 kg ha-1 resulted in maximum plant height (158 cm), number of cobs plant-1
(1.25), number of grain cob-1 (327), thousand grain weight (241 g), grain yield (2415 kg ha-1) and

7. 7
biological yield (7999 kg ha-1) as compared to the minimum values in control plots, 145cm, 0.80,
290, 188 g, 1305 kg ha-1 and 5753 kg ha-1, respectively. The study revealed that phosphorus
should be applied at the rate of 100 kg ha-1 for best grain yield in the agro-ecological conditions
of Peshawar.
Robertson et al (2011) conducted a pot experiment and planted lodgepole pine
(Pinuscontorta var. latifolia) or sitka alder (Alnusviridis ssp. sinuata) seeds in pots containing
field collected forest soils amended with 0, 5, or 10% (dry mass basis) biochar with and without
urea fertilizer (150 mg N kg-1) and concluded that Biochar raised soil pH, exchangeable cations
and cation exchange capacity in some treatments in both soils. Pine had greater biomass in
biochar + fertilizer treatments compared to control and fertilizer only treatments. Alder seedlings
had greater shoot biomass when grown in biochar-amended soils compared with control. The
study showed that biochar addition can enhance soil properties and the early growth of pine and
alder.
Imran et al (2012) conducted a field experiment on integration of biochar with organic
and inorganic sources of phosphorous for improvingmaize productivity in order to study the
integration of biochar with organic and inorganic sources of phosphorous for improving maize
productivity. Two levels of biochar (0 and 25 t ha-1) were allotted to main plots, while two
organic sources (Farmyard manure (FYM) and poultry manure (PM)) and the ratios of (organic
vs SSP) were applied to the field in such a combination that 100%, 75%, 50% and 25% of P was
obtained from the organic sources and the rest was compensated from the inorganic source SSP
and for making a total of 100 kg P ha-1 and concluded that Plots treated with 25 tones biochar ha-
1 produced maximum grains ear-1 (366), 1000 grains weight (285.6 g) and grain yield (4013 kg
ha-1) as compared with control plots. The ratios showed that integration of phosphorous 50 %

8. 8
from organic and 50 % from inorganic phosphorous had maximum ear plant-1 (1.31),
grains row-1 (27), rows ear-1 (14.8), grains ear-1 (374), 1000 grains weight (295.2) and grain yield
(4330 kg ha-1). The interaction between biochar, organic sources and the ratios of (organic vs
SSP) revealed that application of biochar at the rate of 25 t ha-1 with 50 % from organic and 50
% from inorganic phosphorous had maximum 1000 grains weight and grain yield.
Zhang et al (2012) conducted a field experiment to investigate the consistency of biochar
effects on rice production and greenhouse gases emissions. Biochar was applied before rice
transplantation at rates of 0, 10, 20 and 40 t ha−1, soil emissions of carbon dioxide (CO2),
methane (CH4) and nitrous oxide (N2O) were monitored with closed chamber method at 7 days
interval throughout the whole rice growing season. The results showed that biochar amendment
increased rice productivity, soil pH, soil organic carbon, total nitrogen but decreased soil bulk
density. However, biochar amendment decreased nitrous oxide emission, overall GWP (global
warming potential) and GHGI (greenhouse gases emission) were observed significantly
decreased under biochar amendment as compared to control, ranging from 7.1% to 18.7% and
from 12.4% to 34.8%, respectively. However, the biochar effect on corbon intensity of rice
production was observed from 36.9% to 18.6%.
RashidandIqbal(2012) conducted a field study to evaluate the effect of phosphorus
fertilizer on the yield and quality of maize fodder on a clay loam (calcareous) soil and concluded
that yield and quality of maize fodder was improved with phosphorus application. Yield
increased up to 57 kg ha-1with the highest rate of phosphorus application @ 53 kg ha-1. The
quality traits (P concentration, dry matter, crude protein, crude fiber and ash contents were also

9. 9
improved). The study suggested that external and internal phosphorus requirements of
maize fodder to obtain 95 % relative yield were 0.25 mg L-1 and 0.23 mg L-1 respectively.
Cornelissen et al (2013) conducted a field experiment on the effect of biochar on maize
yield and soil characteristics in conservation farming sites,to assess use of a low dosage biochar
combined with CF minimum tillage with maize cob biochar and wood biocharon soils with
variable physical and chemical characteristics and concluded thatthe use low of dosage @4 tons
ha-1, had a strong positive effect on maizeyield (444%and 352%) of the fertilized reference plots
for maize and wood biochar respectively. The study further revealed that the increase in crop
yield was due to increased base saturation (from <50% to 60%) and cation exchange capacity
(CEC; from 2–3 to 5–9 cmolkg-1) and increased plant-available water (from 17% to 21%) as well
as water vapor uptake.
Masto et al(2013)conducted a field experiment to investigate the effects of lignite fly ash
(LFA) and biochar (BC) on soil nutrients, biological properties, and the yield of maize crop and
concluded that soil phosphorus (110%) and pottasium (64%) contents increased by lignite fly ash
+biochar application due to the presence of plant nutrient in biocharandlignite fly ash. Soil
enzymes like dehydrogenase activity (60.7%), alkaline phosphatase (32.2%), fluorescein
hydrolases activity (12.3%) and microbial biomass (25.3%) increased due to integrated
application of lignite fly ash and biochar probably due to the pH-buffering and sorption of the
organic matter to mineral surfaces to create a more reactive network for water, air and nutrient
interactions in the soil. The maize grain yield increased by 11.4% and for biochar, 28.1%.

10. 10
Widowati and Asnah (2013)conducted a field experiment to study the effect of biochar
on potassium fertilizer leaching and uptake,efficiency and effectiveness of K fertilization.The
experiment was comprised of control (without biochar and KCl), K1 (200 kg ha-1KCl), BK0
(biochar, withoutKCl), BK1/4 (biochar + 50 kg ha-1KCl), BK 1/2 (biochar + 100 kg ha-1KCl),
BK 3/4 (biochar + 150 kg ha-1KCl),and BK1 (biochar + 200 kg ha-1KCl) and concluded that
application increased the availability of nutrients by 69-89% for K+,61-70% for Ca++, 39-53% for
N total, 179-208% for P, and 14-184% for K.The study further revealed that the soleapplication
of biochar increased maize production (6.24 Mg ha-1) by 14% compared sole application of
KClfertilizer (5.45 Mg ha-1). The integrated use of biochar and 75% lower dosage of KCl
fertilizer applicationincreased maize production by 29%. Application of biochar and KCl
fertilizer at the rate of 50 kg ha-1 resulted inthe highest relative agronomic effectiveness (137%)
and K fertilizer efficiency (18%).
Wiqar et al (2013) conducted a field experiment on maize yield and soil properties as
influenced by integrated use of organic, inorganic and bio-fertilizers in a low fertility soil and
concluded that combining organic sources with 50% of recommended NPK fertilizers produced
the highest grain and biological yields of maize over the 50% NPK treatment, and obtained the
greatest net result when organic sources were combined with 50% of recommended NPK
fertilizers. Moreover soil analysis after crop harvest showed that soil organic matter, total N,
extractable P and K and EC were all greatest for treatment receiving organic sources with 50% of
recommended NPK fertilizers, on theother hand soil pH was lowest in the corresponding
treatments. Thestudy suggested that integrating organic sources with 50% of recommended NPK
fertilizers are appropriate for sustainable crop production on a low fertility soil.

11. 11
Carter et al (2013) carried out a pot experiment on the impact of biochar application on
soil properties and plant growth lettuce (Lactuca sativa) and cabbage (Brassica chinensis) and
concluded that application of biochar at the rates of 25, 50 and 150 g kg-1 to potting medium
increased the pH of the soil, and contained elevated levels of some trace metals and
exchangeable cations (K, Ca and Mg) in comparison to the soil with no biochar. The biochar
treatments were found to increase the final biomass, root biomass, plant height and number of
leaves in all the cropping cycles in comparison with no biochar treatments. The greatest biomass
increase due to biochar additions (903%) was found in the soils without fertilization, rather than
fertilized soils (483% with the same biochar application.
Kumar et al (2014) conducted a field experiment on impact of biochar on soil health and
concluded that as a soil amendmentbiochar can stabilize carbon belowground and potentially
increase agricultural and forest productivity withadded bonus of environmental function in the
mitigation of diffuse pollution and emissions of trace gases from soil. The study further revealed
thatbiochar alters soil properties, encourages microbial activity and enhances sorption of
inorganic and organic compounds, ability to increase the plant available water in the soil which
enables the plants to survive longer with water shortage, increase soil fertility and agricultural
yields, improve soil structure, aeration, water penetration, and land reclamation.

12. 12
MATERIALS AND METHODS
A field experiment will be conducted to assess the integrated effect of biochar and PK
fertilizer on maize yield and soil properties at the New Research Farm of the University of
Agriculture Peshawar, during summer 2015. The experiment will be laid out in a RCB design
with three replications. The size of treatment plot will be kept 4m by 3.5m. There will be two
factors viz., biochar, phosphorus (SSP) and potassium (SOP) fertilizer. Biochar will be applied at
the rate of 0, 5, 10 and 15 t ha-1, P and K fertilizer at (0, 0), (50, 30) and (100, 60 kg ha-1). The
recommended dose of P and K for maize is 100, 60 kg ha1 respectively. The N (Urea) will be
applied as a basal dose to all treatment plots.
The experiment will be comprised of the following treatment combinations:
Treatment Biochar
(t ha-1)
Phosphorus
(kg ha-1)
Potassium
(kg ha-1)
T1 0 0 0
T2 0 50 30
T3 0 100 60
T4 5 0 0
T5 5 50 30
T6 5 100 60
T7 10 0 0
T8 10 50 30
T9 10 100 60
T10 15 0 0
T11 15 50 30
T12 15 100 60

13. 13
Maize variety Azam will be sown in rows 75 cm apart with plant to plant distance 10 cm after
proper seed bed preparation and experimental lay out as per plan. Biochar and P, K along with ½
of recommended dose of N will be applied before sowing and thoroughly mixed into the soil.
Remaining ½ N will be applied at knee height stage. All recommended cultural practices will be
followed throughout the growing period. Data will be recorded on number of cobs and grain
yield. Grain and plant samples will be collected from each treatment plot at harvest and will be
analyzed for NPK to determine the total nutrient uptake in maize. Data on 1000 grain weight and
shelling % age will also be recorded. Soil samples (0 – 15 cm) will be collected from each
treatment plot after crop harvest and analyzed for soil fertility parameters (S.O.M, total N, total
P, total K, and bulk density).
Agronomic Parameters
Data will be recorded on the following parameters
1. Plant height
From each treatment plot five maize plants will be selected randomly at maturity and
height will be measured in centimeters from soil surface to top and average plant height
will be recorded.
2. Number of cobs plant-1
Data on number of cobs plant-1 will be recorded by counting cobs in five randomly
selected plants in each plot and then average will be taken.
3. Thousand grain weight (g)
Data on 1000 grain weight will be recorded by counting 1000 grains at random and
weighed with the help of electronic balance.

14. 14
4. Biological yield (kg ha-1)
Biological yield will be recorded by weighing dry plants harvest from two central rows of
each plot and then converted into kg ha-1.
Biological yield=
biolgical yield(kg ha−1)
r−r distance x No of rows x row length
𝑥 10000 𝑚2
5. Grain yield
Grain yield will be recorded after shelling dry ears of two central rows from each treatment
plot and will be converted into kg ha-1.
Grain yield (kg ha-1)=
grain yield of two rows
𝑎𝑟𝑒𝑎𝑜𝑓𝑡𝑤𝑜𝑟𝑜𝑤𝑠
x 10,000
6. Strove yield (kg ha-1)
Stover yield will be measured by following formula;
Total biological yield – grain yield = strove yield
Laboratory Analysis
Determination ofsoil pH (Mclean, 1982)and E.C (Richards, 1954)
The pH and E.C of soil samples will be determined in 1:5 soil suspensions. Ten gram of soil sample will
be mixed with 50 ml of distilled water and shaken for 30 minutes. The pH of the suspension will be read
using pH meter and E.C using E.C meter after proper calibration of the instruments.
Bulk density
The bulk density will be determined by core method as described by (Blake and Hartge,
1984). In this method the core sampler (100 cm3) will be inserted in soil up to certain

15. 15
depth to fill the core completely precautions will be followed to avoid the compression.
Soil will be removed from the sides of the core. The obtained soil from core sampler will
be dried at 105 c to a constant weight. The bulk density will be calculated as;
Bulk density=
𝑚𝑎𝑠𝑠
𝑣𝑜𝑙𝑢𝑚𝑒
Determination ofextractable P and K (Soltanpour And Shwab, 1977)
The extractable P in soil sample will be determined in AB-DTPA extract. In this method
10 g soil sample will be shaken with 20 ml of AB-DTPA solution for 15 minutes. After filtering
one ml aliquot will be treated with 5 ml ascorbic acid and make volume up to 25 ml. After 15
minutes of color development aliquot will be read for P on spectrophotometer at 880 nm
however, Pottash will read directly in the AB-DTPA extract on Flame photometer.
Determination of soil Organic matter (Neslson And Sommers, 1996)
One gram of air dried soil sample will be treated with 10 mL of 0.5 N K2Cr2O7 and 20 mL of
concentrated H2SO4.After 30 minutes, 200 mL of distilled water will be added and filtered. After
filtering, 2-3 drops of orthophenantholein will be added and titrated against 0.5 N FeSO4.7H2O.
The volume of FeSO4.7H2O consumed will be noted and calculation will be done to measure the
percent organic matter in the soil by following formula;
%SOM =
meq of K2Cr2O7− meq of FeSO4
weight of soil sample x 0.69
Determination oftotal nitrogen (Bremmer, 1996)
Total N in soil sample will be determined by the Kjeldhal Method of Bremmer (1996).In this
method,0.25 g of the finely ground soil sample will be digested with 3 ml of concentrated H2SO4
in the presence of K2SO4, CuSO4 and Se in 100: 10: 1 ratio. After cooling, the digest will be
distilled with 20 ml of 40% NaOH solution into 5 ml boric acid mix indicator. The distillate will

16. 16
be titrated against 0.01 M HCl and the amount of N will be determined as 1 ml of 0.01 M HCl
equals 140 ug N.
Total % N=
(sample−blank)x 0.005x 0.014 x 100 x 100
weightofsoilsample
Determination of mineral nitrogen (Mulvaney, 1996)
Total mineral N in soil samples will be determined by steam distillation method as described
in Mulvaney (1996). In this method, 20 g of soil sample will be shaken with 100 ml of 1 M
KCl for one hour and filtered. Twenty ml of the filtrate will be distilled with MgO to recover
NH4-N or with MgO + devarday’s alloy to recover total mineral N. The distillate will be
collected in 5 ml boric acid mixed indicator solution and then titrated against 0.005 M HCl.
The total mineral N will be calculated as 1 ml of 0.005 M HCl equals to 70 ug N. The NO3-N
will be determined by subtracting the NH4-N from the total mineral N.
Plant Analysis
The total nitrogen, phosphorus and potassium will be determined by using standard
methods as stated below:
Determination oftotal N in plant sample
Total nitrogen in plant sample will be determined by thekjeldhal method of Bremmer
(1996)as described for determining total N in soil samples.
Determination ofP and K in plant sample
Total phosphorus and K in plant samples will be determined by the wet digestion method
using percholoric and nitric acids as described by Kue (1996). In this method, 1.0 g plant sample
will be digested with 10 ml of concentrated HNO3 and 4 ml of perchloric acid at 100 – 350 C for
1 ½ hours. After cooling the digest will be filtered and diluted to 100 ml. One ml of the digest

17. 17
will be treated with 5 ml ascorbic acid and diluted to 25 ml with distilled water and read for P on
spectrophotometer at 880 nm. Potash will be read directly in the digest or flame photometer.
Statistical analysis and data management
The data will be statistically analyzed by using analysis of variance appropriate for
randomized complete block design. Means will be compared by using LSD test at 5% level of
significance, when the F-values will be significant (Steel and Terrie, 1984).

18. 18
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