MITIGATION OF SALINITY STRESS IN SOYBEAN USING ORGANIC AMENDMENTS

Abstract

A pot experiment was carried out in semi controlled environment at the Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur from November 2015 to March 2016 to assess the effect of organic amendments to mitigate salinity stress in BARI soybean 5. Two types of organic amendments viz. i. water hyacinth compost and ii. rice husk biochar were applied in soil at the rate 5 t/ha and 10 t/ha in both to mitigate salinity stress. Plants were irrigated with 50 and 100 mM sea water from 14 days after sowing (DAS) to maturity and control plants were irrigated with tap water. Data on different physiological parameters like exudation rate, relative water content (RWC), water retention capacity (WRC), water uptake capacity (WUC) and chlorophyll content were measured at flowering stage. Plant height, dry weight of different plant parts, yield and yield contributing characters as well as Na, K, Ca, Mg and Na: K ratio in leaf and stem were also recorded at harvest. Experimental results revealed that salinity decreased plant height, exudation rate, relative water content, water retention capacity, chlorophyll content, dry weight of different parts and K, Ca, Mg content in leaf and stem and finally yield of soybean. Application of water hyacinth compost and rice husk biochar had positive effects to mitigate salinity stress. However, rice husk biochar at the rate of 5 t/ha showed best result to mitigate salinity stress at low salinity (50 mM) condition.

Full text

MITIGATION OF SALINITY STRESS IN SOYBEAN
USING ORGANIC AMENDMENTS
A THESIS
BY
JANNATUL FERDOUS
MASTER OF SCIENCE
IN
AGRONOMY
BANGABANDHU SHEIKH MUJIBUR RAHMAN AGRICULTURAL UNIVERSITY
SALNA, GAZIPUR-1760
AUTUMN, 2016

MITIGATION OF SALINITY STRESS IN SOYBEAN
USING ORGANIC AMENDMENTS
JANNATUL FERDOUS
Registration No.: 14-11-3453
A THESIS
Submitted to
Bangabandhu Sheikh Mujibur Rahman Agricultural University
in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE
Department of Agronomy
Autumn, 2016

MITIGATION OF SALINITY STRESS IN SOYBEAN
USING ORGANIC AMENDMENTS
JANNATUL FERDOUS
Registration No.: 14-11-3453
Certificate of Approval
Prof. Dr. M. A. Mannan
Major Professor and Chairman
Advisory Committee
Prof. Dr. M. Moynul Haque Dr. Mohammad Saiful Alam
Member Member
Advisory Committee Advisory Committee

Dedicated to
My Beloved Father and Mother

MITIGATION OF SALINITY STRESS IN SOYBEAN
USING ORGANIC AMENDMENTS
ABSTRACT
by
Jannatul Ferdous
A pot experiment was carried out in semi controlled environment at the Department of
Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur
from November 2015 to March 2016 to assess the effect of organic amendments to mitigate
salinity stress in BARI soybean 5. Two types of organic amendments viz. i. water hyacinth
compost and ii. rice husk biochar were applied in soil at the rate 5 t/ha and 10 t/ha in both to
mitigate salinity stress. Plants were irrigated with 50 and 100 mM sea water from 14 days after
sowing (DAS) to maturity and control plants were irrigated with tap water. Data on different
physiological parameters like exudation rate, relative water content (RWC), water retention
capacity (WRC), water uptake capacity (WUC) and chlorophyll content were measured at
flowering stage. Plant height, dry weight of different plant parts, yield and yield contributing
characters as well as Na, K, Ca, Mg and Na: K ratio in leaf and stem were also recorded at
harvest. Experimental results revealed that salinity decreased plant height, exudation rate,
relative water content, water retention capacity, chlorophyll content, dry weight of different parts
and K, Ca, Mg content in leaf and stem and finally yield of soybean. Application of water
hyacinth compost and rice husk biochar had positive effects to mitigate salinity stress. However,
rice husk biochar at the rate of 5 t/ha showed best result to mitigate salinity stress at low salinity
(50 mM) condition.

ACKNOWLEDGEMENTS
All praises are due to the Almighty who enabled me to complete the thesis for the degree of
Master of Science (M.S.) in Agronomy.
I feel a proud pleasure and privilege to express my deepest sense of gratitude and indebtedness to
my honorable major professor Dr. M. A. Mannan, Professor, Department of Agronomy,
Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur for his
affection, inspiration, constant guidance, valuable suggestion and instructions throughout the
progress of the research work and in preparation of the thesis.
I also express my respect to the honorable member of my Advisory committee, Dr. M. Moynul
Haque, Professor, Department of Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural
University (BSMRAU), Gazipur for his co-operation, patient guidance, constructive comments,
valuable suggestions and encouragement during the study period.
Profound thanks and indebtedness are also to the honorable member of my Advisory committee,
Dr. Mohammad Saiful Alam, Associate Professor, Department of soil science, Bangabandhu
Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur and all the teachers of
Agronomy Department, Bangabandhu Sheikh Mujibur Rahman Agricultural University
(BSMRAU), Gazipur for their valuable teaching, sympathetic co-operations and inspirations
throughout this study period.
I deeply owe to my relatives, well-wishers and friends for their co-operations, inspirations and
affectionate feelings for the successful completion of my study.
Finally, I express my ever gratefulness and indebtedness to my beloved parents Mahabubur
Rahman Khan and Khadija Begum for their great sacrifice, endless prayers, blessing and support
to reach me at this level of higher education.
The Author
Title Page No.
ABSTRACT I

ACKNOWLEDGEMENTS II
LIST OF CONTENTS III
LIST OF TABLES IV
LIST OF FIGURES V
LIST OF APPENDICES VI
INTRODUCTION 1-3
REVIEW OF LITERATURE
4-10
MATERIALS AND METHODS 11-18
RESULTS AND DISCUSSION 19-43
SUMMARY 44-45
CONCLUSION 46
REFERENCES 47-64
APPENDICES 65
LIST OF CONTENTS
LIST OF TABLES

Table
No.
Title Page
No.
1. Physical and chemical properties of the experimental soil 12
2. Effect of organic amendments on chlorophyll a, chlorophyll b and total
chlorophyll of soybean under saline conditions
27
3. Effect of organic amendments on number of pod/plant and number of
seed/pod of soybean under saline conditions
36
4. Effect of organic amendmens on 100- seed weight and yield of soybean under
saline conditions
38
5. Effect of organic amendments on concentration of Na, K, Ca, Mg and Na: K
ratio in leaf of soybean under saline conditions
41
6. Effect of organic amendments on concentration of Na, K, Ca, Mg and Na: K
ratio in stem of soybean under saline conditions
43
LIST OF FIGURES

Figure
No.
Title Page No.
1. Effect of organic amendments on plant height under saline conditions. 20
2. Effect of organic amendments on exudation rate under saline conditions. 22
3. Effect of organic amendments on relative water content under saline
conditions.
23
4. Effect of organic amendments on water retention capacity under saline
conditions.
24
5. Effect of organic amendments on water uptake capacity under saline
conditions.
26
6. Effect of organic amendments on leaf dry weight under saline conditions. 30
7. Effect of organic amendments on stem dry weight under saline conditions. 31
8. Effect of organic amendments on root dry weight under saline conditions. 32
9. Effect of organic amendments on shoot dry weight under saline conditions. 33
10. Effect of organic amendments on total dry matter weight under saline
conditions.
34
LIST OF APPENDICES

Appendix No. Title Page No.
I. Rice husk biochar analysis: (Chemical analysis) 65
II. Rice husk biochar analysis: (TGI, ash, volatile content analysis) 65
CHAPTER I
INTRODUCTION

Soybean (Glycine max. L) is one of the most important oil seed crop of the world due to high
food value. It contains about 36-40% protein, 18-20% oil, 30% carbohydrate, 7.3% sugar and
9.3% dietary fiber and also contain unsaturated fatty acids, minerals like Ca and P including
vitamin A, B, C and vitamin D (Anonymous, 2012). In Bangladesh, the total cultivated area
under soybean cultivation is 41440 hectares which produces 65883 tons of oil per year (FAO,
2013). The cultivation of soybean is increasing in Bangladesh mostly due to its increasing
demand in the poultry sector.
Agricultural productivity is severely affected by soil salinity and the damaging effect of salt
accumulation in agricultural soils has become an important environmental concern all over the
world (Jaleel et al., 2007). Salinity drastically affects different physiological processes in plant
like water relation traits, chlorophyll degradation, accumulation of organic solutes and other
activities includes photosynthesis (Soussi et al., 1998), nitrogen (Cordovilla et al., 1995;
Mansour, 2000) and carbon metabolism (Delgado et al., 1994; Soussi et al., 1999). Such
physiological changes will result in a decrease in plant growth (Mensah et al., 2006) and
consequently in crop yield. Accumulation of excess Na and Cl in plant body causes ionic
imbalances that may impair the selectivity of root membranes and induce potassium deficiency
(Gadallah, 1999). The deficiency of K initially leads to chlorosis and then causes necrosis (Gopal
and Dube, 2003). Excess soluble salts reduce yields by impairing germination, or creating
osmotic gradients which interfere with the uptake of essential nutrients by plants (Bernstein,
1975; Stamatiadis et al., 1999; Tanji, 1990).
Although agro-climatic condition in Bangladesh is favorable for soybean cultivation, soybean
production is being hampered in some areas of the country due to adverse situation such as
salinity in coastal area of the country. Out of 2.86 million hectares of coastal and offshore lands,

about 1.056 million hectares are affected by varying degrees of salinity (SRDI, 2010). The area
under salinity is increasing with time (from 0.83 m ha to 1.056 m ha in 36 years; SRDI, 2010)
due to rise in sea water level with increased global temperature. A vast area of coastal land in
Bangladesh are remains fallow in winter season due to salinity. Reclamation of saline soil is
difficult. Therefore, alternative ways may be adopted like mitigation of salinity using different
organic amendments. There are evidences that soil amendments with various organic substances
such as farmyard manure, poultry manure and mulch can be used for the reduction of toxic
effects of salinity in various plant species (Idrees et al., 2004; Abou El-Magd et al., 2008; Leithy
et al., 2010; Raafat and Thawrat, 2011). Water hyacinth compost is a dark, crumbly, earthy-
smelling mixture that consists mostly of decayed organic matter. Composts are widely used as
sources of nutrients and organic matter. The beneficial influence of compost on soil physical and
chemical properties has been well documented (Debosz et al. 2002; Lynch et al. 2005; Tejada et
al. 2006; Wanas and Omran, 2006). Biochar is pyrolysed organic material intended for use as a
soil amendment to sustainably sequester C and concurrently improve soil function, while
avoiding any adverse effects, on both the short and long terms (Lehmann and Joseph, 2009;
Verheijen et al., 2009). Biochar enhanced soil water-holding capacity (Asai et al., 2009; Laird et
al., 2010); improved soil water permeability (Asai et al., 2009); improved saturated hydraulic
conductivity (SHC) (Asai et al., 2009); reduced soil strength (Chan et al., 2007, 2008) and
modification in soil bulk density (ρb) (Laird et al., 2010). Dramatic improvement of soil
chemical properties have been reported with biochar applications to agronomic soils (Chan et
al., 2007; Laird et al., 2010). However, role of organic amendments to mitigate soil salinity in
Bangladesh is not clearly understood. The aim of this research work was to mitigate the adverse

effects of soil salinity in soybean by organic amendments. However, specific objectives of the
present study were:
To evaluate the growth and yield of soybean in response to water hyacinth compost
and rice husk biochar under salinity stress;
To find out the effect of application of water hyacinth compost and rice husk
biochar on some physiological parameters related to salinity tolerance in plants;
and
To determine appropriate organic amendment rate that could effectively mitigate
the adverse effect of salinity on soybean.
CHAPTER II
REVIEW OF LITERATURE

Salinity is one of the most serious factors limiting the productivity of agricultural crops, with
adverse effects on seed germination, plant growth and crop yield. Cultivated crops under saline
condition face at least two types of stresses viz., one stress for ion toxicity and the other arises
from low water availability. A large number of researchers throughout the world have carried out
research works about the effects of salinity stress on various crops including soybean. Some of
the relevant works and their findings in connection with the present work have been reviewed
and presented in this chapter.
Effects of salinity on plants
Babu and Thirumurugan (2001) conducted a pot experiment to study the effect of salt priming on
growth and development of sesame under induced salinity condition and observed that plant
height decreased with the increased salinity levels. Similar result was also observed by Ragiba
(2000) in sesame. An experiment with 26 parental lines of hybrid rice was conducted by Islam et
al. (2011) in saline micro plots. Result revealed that plant height decreased with increasing
salinity level. Plant height is one of the important growth parameters that influence the yield. An
experiment was carried out by Hasanuzzaman et al. (2009) and observed that plant height was
negatively influenced by different salinity levels in all the rice varieties. Plant height
progressively decreased with increased in salinity levels as reported by Saxena and Pandy
(1981). Similar results were reported by many workers (Khan et al., 1997; Poway and Mehta,
1997; Hossain, 2006). An investigation was made by Cha-um et al. (2007) with the objective to
evaluate the effective salt-tolerance defense mechanisms in aromatic rice varieties. Sanker
(2007) carried out a pot experiment to study the effect of salinity on growth and development of
lentil under induced salinity condition (6 dS/m) and observed that stem and leaf weight
decreased under salinity condition compared to control. Rashid (2005) found that salinity

induced a marked reduction in plant height, branch number, root and stem weight and leaf area
of studied lentil genotypes. Similar results also reported by many workers in lentil (Singh et al.,
2003; Islam, 2004; Jahan, 2006). Further, Ali et al. (2004) found that salinity induced a mark
reduction in plant biomass production of the studied genotypes. Debnath (2003) and Rahman
(2003) worked with mustard to know the effect of different levels of salinity (5, 7, 10 and 15
dS/m) on yield attributes and dry matter partitioning and reported that harvest index decreased
with increased salinity levels. Singh et al. (2003) carried out an experiment involving 4
genotypes and three levels of salinity (0, 8 and 12 dS/m) and reported that shoot dry weight
decreased with increasing soil salinity concentration. Similar result were also observed by many
workers in lentil (Islam, 2006; Islam, 2004; Rashid, 2005; Jahan, 2006; Islam et al. 2006; Sanker
2007). Rymar et al. (1986) reported that increasing salinity levels decreased the height, root
length, fresh weight and dry weight accumulation of rice seedling.
Hakim (2003) conducted a pot experiment with two high yielding varieties and a hybrid under
different salinity levels and reported that plant height, number of tillers /plant, number of
panicles /plant, number of grains /panicle, length of panicle, 100-grain weight, and grain yield
were decreased with increasing salinity level. Balsubramania and Rao (1977) stated that in a pot
trial, 4 rice strains were grown in soil irrigated with saline water of electrical conductivity of 4
dS/m (low salt stress) or 8 dS/m (high salt stress). Grain yield per plant was 2.879 g with low
stress, 2.2- 6.6 g with high stress and 8.5-13.7 g in the unstressed control. The yield reduction
was mainly due to decrease in the number of panicles /plant.
Khan et al. (1997) observed that number of tillers was decreased with increasing salinity levels
imposed at all growth stages in rice. Similar results were also reported by many workers in rice
(Islam et al., 2004; Burman et al., 2002; Islam, 2006 and Rashid, 2005). Linhe et al. (2000)

further reported that decreased tiller number was the major causes of yield loss under salinity
stress. The effect of salinity on cultivars of champa rice was studied at various stages of growth
by Mortazainezhad et al. (2006). Rashid (2005) conducted a pot experiment with 3 salinity levels
(0, 4 and 6 dS/m) and observed that 100 seed weight decreased with increasing salinity level in
lentil. Islam et al. (2006) reported that seed size decreased with increased salinity level in lentil.
Similar results are also observed by many researchers (Singh et al. 2003; Islam 2004; Sanker,
2007). Sen (2002) conducted a pot experiment with three salinity levels (3, 6 and 9 dS/m) and
observed that 1000-grain weight decreased with increased salinity levels in rice. Similar results
were also reported by Abudullah et al. (2001) who observed that 1000-grains weight decreased
with increased salinity levels.
Islam (2004) carried out an experiment to evaluate the effect of salinity on yield and yield
attributes of rice and reported that number of filled grains/ panicle was decreased with increased
salinity levels. A study was designed by Zeng et al. (2003) to determine the interactive effects of
salinity and water depth on seedling establishment and grains yield of rice. The effects of both
salinity and water depth were significant on plant growth and grain yields. Lee et al. (2002)
showed that yield and yield components, except for panicle number, were decreased most by the
high salinity treatment regardless of the growth stage. Water culture studies of short- term
(seedling stage) and long-term (maturity) stage were conducted by Aisha et al. (2005) to evaluate
the effect of different levels of salinity. Qadar (1995) reported that elevated salinity levels
significantly decreased the total and filled grains /panicle and 1000-grains weight which resulted
decrease grains yield. Similarly, Soliman et al. (1994) conducted a greenhouse experiment and
found that grains yield reduced under saline condition.

An experiment was conducted by Dogan et al. (2011) on soybean (Glycine max. L.) to
investigate the plants protective mechanisms against salt induced oxidative stress. The results
showed that K/Na ratio was decreased with increasing salinity. The high Na adsorption capacity
of biochar has also been recently reported by Thomas et al. (2013). A greenhouse experiment
was conducted by Miah et al. (1992) at IRRI with three levels of salinity (2.4, 6.0 and 11.8
dS/m), four levels of P (0, 25, 50 and 100 mg/kg soil) and two rice varieties. They reported that
salinity decreased K concentrations and increased Na concentrations both in grain and straw. The
cultivar 1R26 had a higher concentrations of Na and a lower concentrations of K at increased
salinity levels than had 1R9884-54-3. Karmoker et al. (2008) conducted an experiment on effects
of salinity in maize and they showed that the accumulation of Na and cl- increased but K
accumulation decreased with the increase in salinity concentration from 50 to 200 mM in the
root and shoot of maize in all the three ages. It has been well documented that increased Na in
the soil solution decreases uptake of K, Ca, N and other essential nutrients (Ashraf et al., 2004).
Mitigation of salinity effects on plant by organic amendments
Composts are widely used as sources of nutrients and organic matter. The beneficial influence of
compost on soil physical and chemical properties has been well documented (Debosz et al.,
2002; Lynch et al., 2005; Tejada et al., 2006; Wanas and Omran, 2006). Shazia et al. (2004)
conducted an experiment on the effects of increasing soil fertility with sulphate of potash (SOP)
and/or farm-yard manure (FYM) on salt tolerance of two sugarcane varieties i.e. SPSG-26, and
CP77-400. They found that FYM and potash fertilizer significantly reversed the effects of
salinity, increased nitrate reductase activity (NRA), transpiration rate, flag leaf area, cane yield
and sugar recovery and decreased stomatal diffusive resistance. Biochar is considered to be an
ideal amendment to increase nutrient and water retention in soil, thereby enhancing crop growth

and yield (Akhtar et al., 2014). Despite numerous observations in both field and controlled
experiments showing that plant yield increases due to biochar additions (Chan and Xu, 2009;
Graber et al., 2010; Jeffery et al., 2011; Lehmann et al., 2015; Van Zwieten et al., 2010), the
exact mechanistic background of biochar effects is not known. Investigation of the effects of
biochar on crop growth has increased over the past years but has mainly concentrated on tropical
soil (Lehmann et al. 2003; Yamato et al. 2006; Chan et al. 2007, 2008; Steiner et al. 2007;
Kimetu et al. 2008; Hidetoshi et al. 2009; Yeboah et al. 2009; Gaskin et al. 2010; Major et al.
2010; Van Zwieten et al. 2010). Increased growth with biochar under salinity stress might be
explained by three mechanisms of action, as reported by Akhtar et al. (2015). An experiment was
conducted by Reddy and David (2012) of lettuce, tomato and blueberry in saline soil. Though
composts contain nutrients and can improve soils, there is widespread concern among growers in
arid and semiarid regions about their salt content. However, in all cases, plant growth rates of
lettuce, tomato and blueberry were significantly increased relative to the fertilized control
suggesting that the benefits of compost use outweigh the possible negative influence of compost
salts. At typical agricultural application rates, salinity added with compost amendments is
unlikely to negatively impact plant growth. Biochars affect soil properties differently depending
on feedstock and pyrolysis conditions, strongly differing in pH, nutrient contents and ion
exchange capacities reported by Lehmann and Joseph, 2015. By supplying additional nutrients
and by improving soil structure, composts also may mitigate symptoms associated with saline
soils and compost use has been suggested as a means of remediating this condition (Hanay et al.,
2004; Tejada et al., 2006). An experiment was conducted by Akhter et al. (2015) to study the
interactive effect of biochar and plant growth-promoting endophytic bacteria containing 1-
aminocyclopropane-1-carboxylate deaminase and exopolysaccharide activity on mitigating

salinity stress in maize (Zea mays L.). The results indicated that salinity significantly decreased
the growth of maize, whereas both biochar and inoculation mitigated the negative effects of
salinity on maize performance either by decreasing the xylem Na concentration ([Na] xylem)
uptake or by maintaining nutrient balance within the plant, especially when the two treatments
were applied in combination. Moreover, in biochar-amended saline soil, strain FD17 performed
significantly better than did PsJN in reducing [Na] xylem. The results suggested that inoculation
of plants with endophytic baterial strains along with biochar amendment could be an effective
approach for sustaining crop production in salt-affected soils. The potential for biochar to
positively affect crop growth are various, through effects on a range of chemical and physical
phenomena in soil, that in turn impact on biological processes in the plant, soil and rhizosphere
(root zone). Roots are the first point of contact between biochar particles and plants. Root
responses have generally been limited to biomass measurements in biochar studies (Lehmann et
al., 2003; Noguera et al., 2010; Prendergast-Miller et al., 2011). The potential of biochar to abate
salt stress in plants is still under-researched. To our knowledge, there are only very few recent
studies examining the effect of biochar on plant growth under salinity (Lashari et al., 2013;
Thomas et al., 2013; Lashari et al., 2015). Lashari et al. (2013, 2015) used a biochar manure
compost, i.e. a mixture of pyrolysed carbon and fresh organic matter, which ameliorated salt
stress, but the mechanisms behind this remained unsolved. Lax et al. (1994), Komor (1997),
Smith et al. (2001), Munns (2002),Walker and Bernal (2004) and Fathi (2010) found that the
biological amelioration methods using living or dead organic matter (green manure, barnyard
manure, compost, and sewage sludge) have two principal beneficial effects on reclamation of
saline and alkaline soils: i) improvement of soil structure and permeability thus enhancing salt
leaching, reducing surface evaporation, and inhibiting salt accumulation in surface soils and ii)

release of carbon dioxide during respiration and decomposition. Thomas et al. (2013) added salt
over a top dressing of biochar to forb pot cultures and concluded that biochar ameliorated salt
stress through salt sorption, as biochar material showed strongly increased conductivity
following salt addition. Soil amendments influence infiltration rates, bulk density, structure,
compaction, and aggregate stability and crust hardness (Helalia and Letey, 1989). We also found
a clear amelioration of salt stress in plants after biochar amendment in combination with reduced
salt strength in both plants and soil. Biochar can retain significant amounts of cations on its
surface (Liang et al., 2006; Chan and Xu, 2009), and surface affinities to Na may differ
comparted than to K ions. Biochar can affect nutrient release, retention or immobilization
(Blackwell et al., 2010) also by its surface properties. 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 to no biochar treatments reported by Jeffery et al. (2011).
CHAPTER III
MATERIALS AND METHODS

3.1 Location of the experimental site
The experiment was conducted under semicontrolled environment at the Department of
Agronomy, Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) Gazipur
from November 2015 to March 2016. The experimental site was located at 24.090 N latitude and
90.260 E longitudes at an elevation of 8.4 m from the mean sea level, with an average 12.3/11.7
hour light/dark period during the experimental period.
3.2 Experimental materials
3.2.1 Biochar production
Biochar used for the experiment was produced from rice husk by pyrolysis using biochar stove
developed by (Mia et al., 2015) and modified by Mannan, M. A. (unpublished). Rice husk was
collected from local rice mill. Then it spread on a polythene sheet for sun drying and this
feedstock was used for biochar production.12 kg dry rice husk was pyrolysed by 5 kg fuel (dry
wooden stem) and produced biochar was 5 kg. About 7 hours time was required for the
preparation of biochar. Nutrient content, TGI (Thermo Gravimetric Index), ash, volatile content
analysis of rice husk biochar was done and presented in Appendix I and Appendix II.
3.2.2 Compost production
Water hyacinth was used to produce compost. It was collected from local cannel and then kept it
in a pit for two months for decomposition.
3.2.3 Preparation of experimental pot

The soil for experiment was collected before sowing of seeds. Physical and chemical properties
of the soil was determined and presented in table 1.
Table 1. Physical and chemical properties of the experimental soil
Soil properties Analytical value
Sand (%) 40.42
Silt (%) 29.16
Clay (%) 30.42
Texture Clay loam
pH 6.93
Organic carbon (%) 0.61
Total Nitrogen (%) 0.07
Available phosphorus (ppm) 10
Exchangeable K (meq/100g soil) 0.20
CEC (meq/100g soil) 15.02
Plastic pots with 30 cm length and 24 cm diameter was used in the experiment. Each pot
received a uniform weight of 11 kg air dry soil or a soil and rice husk biochar or soil and water
hyacinth compost mixture. Biochar and compost were applied at the rate of 5 and 10 t/ha for each
pot and it was 24.4g and 48.8 g, respectively. Inorganic fertilizers were applied as 60-175-120-
115 kg/ha through urea, triple superphosphate, muriate of potash and gypsum as the
recommendation of BARI (2005). Biochar, compost and all fertilizers were added during final
soil preparation for pot filling. A total of forty five (45) pots were filled up by soil or soil and
biochar or soil and compost mixture. Then all pots were placed in vinyl house under semi control
condition.
3.2.4 Planting material

Soybean variety BARI soybean 5 was used as planting material and seeds were collected from
Bangladesh Agricultural Research Institute, Joydebpur, Gazipur.
3.2.5 Treatments
Factor A: Salinity levels: 3
i.) Control (tap water)
ii) 50 mM sea water
≅
5 ds/m
iii) 100 mM sea water
≅
10 ds/m
Factor B: Organic amendments types: 2
i.) Water hyacinth compost at the rate of 5 t/ha and 10 t/ha
ii.) Rice husk biochar at the rate of 5 t/ha and 10 t/ha
3.2.6 Saline solution preparation
Saline solution was prepared by mixing sea water with tap water to get the required concentrate
of solution. EC meter was used to measure the required EC value of the saline solution.
3.2.7 Treatment combination
The following treatment combinations were applied
1. Control
2. 50 mM sea water
3. 100 mM sea water
4. Control × 5 t/ha compost
5. Control ×10 t/ha compost
6. 50 mM sea water × 5 t/ha compost
7. 50 mM sea water × 10 t/ha compost
8. 100 mM sea water × 5 t/ha compost
9. 100 mM sea water × 10 t/ha compost
10. Control × 5 t/ha biochar
11. Control × 10 t/ha biochar
12. 50 mM sea water × 5 t/ha biochar
13. 50 mM sea water × 10 t/ha biochar
14. 100 mM sea water × 5 t/ha biochar
15. 100 mM sea water × 10 t/ha biochar
Salinity stress with sea water treatment was imposed at 1st trifoliate leaf (14 days after sowing)
stage. In control treatment, tap water was applied. The treatments were continued until
harvesting as and when necessary.

3.3 Experimental design
The experiment was laid out in Completely Randomized Design (CRD) with three replications.
Each replication was divided into 15 unit pots where the treatments were allotted randomly.
3.4 Raising of seedlings
Ten seeds were sown in each plastic pot on 15 November 2015. Light irrigation was given by
the water cane to ensure uniform germination of seeds after sowing.
3.5 Intercultural operations
Thinning: Thinning was done at the appearance of first trifoliate leaf stage and kept six uniform
and healthy plants in each pot.
Weeding: Weeding was done intensively to keep the pots weed free.
Pesticide application: To protect the plant from noxious insects Ripcord 10 EC @ 1 ml/liter of
water was sprayed when it was needed.
Fertilizer application
Full doses of chemical fertilizers viz. TSP (0.86 g /pot), MP (0.59 /pot) and gypsum (0.56g/ pot)
were added to soils during pot preparation. Urea was applied in two split doses; first dose (0.15 g
/pot) was applied during final pot preparation, second dose (0.15 g/ pot) was applied during 8-10
leaf stage.
3.6 Data collection
A brief outline of the data recording procedure is given below-
Plant height

Height of individual plant was measured using meter scale from the base at the ground level of
the pot to the tip of all sampled plants. Plant height was measured during harvesting.
Exudation rate
Xylem exudation rate was measured at 5 cm above from the stem base of plant at flowering
stage.
Exudation rate = [(Weight of cotton + sap) – (Weight of cotton)] /Time (h)
Water related data: The following water related data were recorded at flowering stage.
Relative water content (RWC)
Relative water content (RWC) was determined at flowering stage using following formula
according to Schonfeld et al. (1988):
RWC (%) = [(FW DW)/(TW DW)] × 100˗ ˗
Where, FW = Fresh weight of the leaf
DW = Dry weight of the leaf
TW = Turgid weight of the leaf
Water Retention Capacity (WRC)
WRC =
TW
DW
Where, TW = Turgid weight of the leaf
DW = Dry weight of the leaf
Water Uptake Capacity (WUC)

WUC=
TW −FW
DW
Where, TW = Turgid weight of the leaf
FW = Fresh weight of the leaf
DW = Dry weight of the leaf
Chlorophyll content
Chlorophyll content was estimated from the fully expanded uppermost leaf samples at flowering
stage had imposed using the method described by Witham et al. (1986).
Reagent: Acetone (80%)
Procedure:
The fresh leaf sample of 20 mg were taken in small vials containing 20 ml of 80% acetone and
covered with aluminum foil and preserved in the dark for 72 hours. Then reading was taken at
663 nm and 645 nm wavelengths by a visible spectrophotometer (Model: T 60 U) and the result
was expressed as mg g-1 fresh weight. The formula for computing chlorophyll a, b and total
chlorophyll were-
Chlorophyll a (mg/g fresh weight) = [12.7 (D663) – 2.69 (D645)] × [V/1000 × W]
Chlorophyll b (mg/g fresh weight) = [22.9 (D645) – 4.68 (D663)] × [V/1000 × W]
Total Chlorophyll (mg/g fresh weight) = [20.2 (D645) + 8.02 (D663)] × [V/1000 × W]
Where,
D (663, 645) = Optical density of the chlorophyll extract at wave length of 663 and 645 nm
respectively.

V = Final volume (ml) of the 80% acetone with chlorophyll extract.
W = Weight of fresh leaf sample in g.
Dry matter partitioning
At maturity stage crop was harvested. After harvest soil was washed out gently by tap water and
plants were partitioned into root, stem, leaf and pod. The plant parts were oven dried at 700C for
72 hours. Total dry weight (DW) was calculated by summing up the roots, stem and leaf of the
plants. Shoot DW was calculated by excluding dry weight of root from total dry weight.
Yield and yield contributing parameters
Yield and yield contributing characters like pod per plant, seed per pot, 100-seed weight and
yield per plant were recorded. Seeds were dried in the sun up to the seed moisture content 10%.
Then 100-seed weight was measured by using electrical balance.
3.7 Plant sample analysis
Sodium (Na), potassium (K), calcium (Ca), magnesium (Mg) content in leaf and stem
Na, K, Ca, Mg content was determined after crop harvesting by extracting plant samples with 1N
NH4OAc solution. 0.5 g plant sample and 6 ml di-acid were heated for 2 hour in sand bath and
then kept it overnight to settle. Then it was filtered in 100 ml conical flask. Then 5 ml filtrate was
taken in a 50 ml volumetric flask and 1 ml LaCl3.7H2O was added to it and volume was made up
to the marked level. Then reading was taken by using flame photometer. This method was
proposed by Brown and Lilleland (1946).
3.8 Soil sample analysis

Initial soil sample was analyzed for different physical and chemical properties like soil texture,
pH, organic carbon, N, P, K and CEC following standard methods.
3.9 Statistical analysis
The recorded data were statistically analyzed by “CROPSTAT 7.2” software to examine the
significant variation of the results due to different treatments. The treatment means were
compared by Least Significance Difference (LSD) test at 5% level of significance (Gomez and
Gomez, 1984).
CHAPTER IV
RESULTS AND DISCUSSION
The present experiment was carried out in order to observe the effect of salt stress on the growth
and yield of soybean as well as to mitigate the adverse effect of salt stress by organic
amendments. The data obtained on different parameters of soybean variety are presented and
discussed in this chapter.
4.1. Plant height

Soil salinity caused a significant effect in plant height of soybean. At control, plant height was
found 17.3 cm but it was 17.7 cm and 15.0 cm under 50 mM and 100 mM salinity levels,
respectively (Fig. 1). It was observed that plant height increased at 50 mM salinity level than
control because lower level of salinity acts as nutrient of plant growth. At 100 mM sea water
treatment caused a drastic decreased in plant height and it indicates that high level of salinity was
harmful for plant height. Organic amendments significantly increased the plant height of soybean
under both control and salt stress conditions. At control condition highest plant height (23.0 cm)
was found when soil was treated with biochar @ 10 t/ha and the lowest height (19.3 cm) was
found when water hyacinth compost was added in the soil @ 10 t/ha. At 50 mM salinity stress
highest plant height (22.0 cm) was recorded when soil was treated with water hyacinth compost
@ 10 t/ha and the lowest height (19.7 cm) was observed when soil was treated with compost @ 5
t/ha but similar plant height also recorded from biochar amendment @ 10 t/ha. On the other hand
under 100 mM salinity stress the tallest plant (20 cm) was found when soil was treated with
biochar @ 10 t/ha and the shortest plant (16.7 cm) was obtained from compost amendment @ 5
t/ha. Results indicated that plant height decreased with increasing salinity level and varied with
different organic amendments.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.0
5.0
10.0
15.0
20.0
25.0
Treatments
Plant height (cm)
Fig. 1. Effect of organic amendments on plant height under saline conditions. Bars indicate
SE (±).
Islam et al. (2011) and Miah (1992) found that plant height decreased with increasing salinity
levels in different rice varieties. Leithy et al. (2010), Abou El-Magd et al. (2008) and Raafat and
Tharwat (2011) have shown that different organic amendments increased plant height at different
levels of soil salinity on peanut, sweet funnel and rice, respectively. Kamara et al. (2015) also
reported that rice plants grown on soils treated with rice straw biochar were significantly (p <
0.05) taller than those grown on soils without biochar treatment. The results showed the positive
influence of rice straw biochar on plant height for rice varieties.
4.2. Exudation rate
When vigorously growing stem of plants are cut off just above ground level, large quantities of
sap may be seen to exude from root stumps. This phenomenon is called exudation. Naturally,
exudation rate of plant is slower in any stress condition than under normal condition. Decrease in

exudation rate indicate lower water uptake by plant. Salinity decreased the exudation rate
drastically in soybean plant and decreasing rate was higher with increasing salinity levels (Fig.
2). The lowest exudation rate (178 mg/h) was found at 100 mM salt stress level when no organic
amendment was applied in the soil. Compost and biochar amendments increased the exudation
rate of soybean plant both in control and saline conditions. At control condition highest
exudation rate (903 mg/h) was observed when biochar was added in the soil @ 5 t/ha and it was
lowest (659 mg/h) when soil was treated with compost @ 5 t/ha. At 50 mM salinity stress highest
exudation was 458 mg/ha when compost was added @ 5 t/ha. On the other hand lowest
exudation was 417 mg/ha when soil was treated with biochar @ 5 t/ha. At 100 mM salinity stress
maximum exudation (332 mg/h) was observed in the treatment when biochar was added @ 5 t/ha
and it was minimum (284 mg/h) when soil water hyacinth compost was added @ 5 t/ha in the
soil. In a study, there was clear evidence of amendment soil interaction processes affecting both
soil properties and and exudation rate particularly for biochar, that might lead to greater changes
with additional field emplacement time reported by Mukherjee et al. (2014). Salinity induced
reduction of xylem exudation rate was also observed by many investigators (Papadopoulos et al.,
1987; Pessarakli and; Kabir et al., 2005).
4.3. Relative water content
Relative water content (RWC) is consider as a measure of plant water status, reflecting the
metabolic activity in tissues and used as a most meaningful index for dehydration tolerance
(Anjum et al., 2011). RWC of control plant of soybean was greater than that of the salt treated
plant. RWC was decreasing with increasing salinity levels (Fig. 3).

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0
100
200
300
400
500
600
700
800
900
1000
Treatments
Exudation rate (mg/h)
Fig. 2. Effect of organic amendments on exudation rate under saline conditions. Bars
indicate SE (±).
The control treatment showed 89% RWC and it reduced to 73% at 100 mM salinity level.
Organic amendment significantly increased RWC of soybean under control and saline
conditions. Highest RWC (93.67%) was observed when biochar was added @ 5 t/ha and lowest
RWC (88.67%) was when biochar was added @ 10 t/ha under control condition. At 50 mM
salinity condition, highest RWC (88%) was obtained from compost @ 5 t/ha and lowest RWC
(84%) was observed when biochar was applied @ 5 t/ha. Under 100 mM saline condition highest
RWC (78.33%) was obtained when soil was treated with compost @ 5 t/ha and it was lowest
(76.33%) when biochar was added in the soil @ 5 t/ha. Salinity induced decrease of RWC was
also reported by Serraj and Drevon (1988) in alfalfa, Nandwal et al. (2000) and Stoyanov (2005)
in young bean, Kabir et al. (2005) in mungbean. Tryon (1948) showed that available soil
moisture and relative water content (RWC) in a sandy soil increased linearly with increasing
wood biochar application rate.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0
10
20
30
40
50
60
70
80
90
100
Treatments
Relative water content (%)
Fig. 3. Effect of organic amendments on relative water content under saline conditions.
Bars indicate SE (±).
4.4. Water retention capacity
Water retention capacity (WRC) of leaf is the capacity of plant cell to retain water. Soil water
retention capacity is a potential indicator of soil quality and productivity. Salinity decreased the
WRC significantly in soybean plant and the decreasing rate was higher with increasing salinity
levels (Fig. 4). Plant growth under an optimum moisture regime maintains a higher ratio that
could be due to the lower destruction of plant tissues by moisture deficit (Sangakkara et al.,
1996). Organic amendments significantly increase WRC of soybean among 5 t/ha and 10 t/ha
compost and biochar treatment at 0 mM, 50 mM and 100 mM salinity levels.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
Treatments
Water retention capacity
Fig. 4. Effect of organic amendments on water retention capacity under saline conditions.
Bars indicate SE (±).
In case of biochar, WRC were significantly increased by biochar treatment at every salt stress
level. Highest WRC (8.2) was observed when biochar was added @ 5 t/ha and it was 7.6 when
biochar was added @ 10 t/ha under control condition. At 50 mM salinity condition highest WRC
(6.5) was obtained from biochar @ 5 t/ha and lowest WRC (5.4) was observed when compost
was applied @ 5 t/ha. Under 100 mM saline condition highest WRC (4.4) was obtained when
soil was treated with compost @ 5 t/ha and it was lowest (3.8) when biochar was added in the
soil @ 10 t/ha. Organic amendments like compost has beneficial effects on reclamation of saline
soils through improvement of soil structure and permeability thus enhancing salt leaching,
reducing surface evaporation, and inhibiting salt accumulation in surface soils (Raychev et al.,
2001). The impact of biochar on soil WRC was most likely related to an effect in overall porosity
of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro

porosity with 0.5 and 1.6% for each Mgha−1 of biochar applied, respectively observed by
Carvalho et al. (2014). Biochar can improve plant productivity directly as a result of its nutrient
content and release characteristics, as well as indirectly, via: improved soil physical properties
(Chan et al., 2008), including an increase in soil water retention (Laird et al., 2010).
4.5. Water uptake capacity
Salinity had a remarkable effect on water uptake capacity (WUC) of soybean plant (Fig. 5).
WUC was increased with increasing soil salinity and highest (1.36) was found at 100 mM salinty
level. Organic amendments significantly decreased the WUC of soybean with compost and
biochar treatment at 0 mM, 50 mM and 100 mM salt level. Highest decrease of WUC (0.26) was
observed when biochar was added @ 5 t/ha and it was 0.33 when biochar was added @ 10 t/ha
under control condition. At 50 mM salinity condition, lowest WUC (0.53) was obtained from
biochar @ 5 t/ha and highest WUC (0.71) was observed when compost was applied @ 5 t/ha. At
100 mM saline condition lowest WUC (1.06) was obtained when soil was treated with biochar @
10 t/ha and it was highest (1.17) when compost was added in the soil @ 10 t/ha. Biochar may
alter the physical properties of the soil, including increasing aeration and water holding capacity
of certain saline soils reported by Sohi et al. (2010); Jeffery et al. (2011); Verheijen et al. (2012)
and Haefele et al. (2011) which helps to increase seedling resistance to wilting and can increase
water holding capacity (WHC) top soil was also reported by Case et al. (2012) and Mulcahy et
al. (2013). Inorganic ion accumulation is significant in osmotic adjustment and facilitates water
uptake along a soil-plant gradient (Khan et al., 1999).

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
Treatments
Water uptake capacity
Fig. 5. Effect of organic amendments on water uptake capacity under saline conditions.
Bars indicate SE (±).
4.6. Chlorophyll content
4.6.1 Chlorophyll a
Organic amendment significantly increased chlorophyll a of soybean under control and saline
conditions (Table 2). Highest chlorophyll a (3.21 mg/g) was observed when biochar was added
@ 5 t/ha and it was 2.72 mg/g when compost was added @ 5 t/ha under control condition. At 50
mM salinity condition highest chlorophyll a (2.43 mg/g) was obtained from biochar @ 5 t/ha and
lowest chlorophyll a content (2.15 mg/g) was observed when biochar was applied @ 10 t/ha. At
100 mM saline condition highest total chlorophyll (1.86 mg/g) was obtained when soil was
treated with compost @ 5 t/ha and it was lowest (1.48 mg/g) when biochar was added in the soil
@ 10 t/ha. Increasing salinity concentration in the rooting medium significantly reduced the
chlorophyll a, chlorophyll b, and total chlorophyll (Ashraf et al., 1989).

Table 2. Effect of organic amendments on chlorophyll a, chlorophyll b and total chlorophyll
of soybean leaf under saline conditions
Treatments Chlorophyll a
(mg/g fresh wt.)
Chlorophyll b
(mg/g fresh wt.)
Total chlorophyll
(mg/g fresh wt.)
Control 2.54 1.85 4.39
50 mM sea water 1.81 1.80 3.61
100 mM sea water 1.27 1.01 2.28
0 x 5 t/ha compost 2.72 1.91 4.63
0 x 10 t/ha compost 2.94 1.59 4.53
50 x 5 t/ha compost 2.33 1.48 3.81
50 x 10 t/ha compost 2.26 1.53 3.79
100 x 5 t/ha compost 1.86 0.63 2.49
100 x 10 t/ha compost 1.61 1.04 2.65
0 x 5 t/ha biochar 3.21 1.57 4.79
0 x 10 t/ha biochar 2.99 1.73 4.72
50 x 5 t/ha biochar 2.43 1.23 3.67
50 x 10 t/ha biochar 2.15 1.59 3.74
100 x 5 t/ha biochar 1.58 1.00 2.59
100 x 10 t/ha biochar 1.48 0.90 2.38
LSD (5%) 0.20 0.32 0.23
CV (%) 5.5 14.1 3.8
4.6.2 Chlorophyll b
Chlorophyll b content of soybean plant also was reduced significantly at salinity stress
conditions (Table 2). It was significantly lowest at 100 mM salt level than control. Organic
amendment significantly increased chlorophyll b of soybean plant under control and saline
conditions. Highest chlorophyll b (1.91 mg/g) was observed when compost was added @ 5 t/ha
and it was 1.57 mg/g when biochar was added @ 5 t/ha under control condition. At 50 mM
salinity condition, highest chlorophyll b (1.59 mg/g) was obtained from biochar @ 10 t/ha and
lowest chlorophyll b (1.23 mg/g) was observed when biochar was applied @ 5 t/ha. Under 100
mM saline condition highest chlorophyll b content (1.04 mg/g) was obtained when soil was

treated with compost @ 10 t/ha and it was lowest (0.63 mg/g) when compost was added in the
soil @ 5 t/ha. Both chlorophyll a and chlorophyll b decreased with increasing salinity. Our
findings are in line with the findings of Hajer et al. (2006).
4.6.3 Total chlorophyll
Total chlorophyll of soybean plant also was reduced significantly at salinity conditions.
Chlorophyll content was increased after amendment application (Table 2). Organic amendment
significantly increased total chlorophyll of soybean under control and saline conditions. Highest
total chlorophyll (4.79 mg/g) was observed when biochar was added @ 5 t/ha and the lowest was
4.53 mg/g when compost was added @ 10 t/ha under control condition. At 50 mM salinity
condition, highest total chlorophyll (3.81 mg/g) was obtained from compost @ 5 t/ha and lowest
total chlorophyll (3.67 mg/g) was observed when biochar was applied @ 5 t/ha. At 100 mM
saline condition, highest total chlorophyll (2.65 mg/g) was obtained when soil was treated with
compost @ 10 t/ha and it was lowest (2.38 mg/g) when biochar was added in the soil @ 10 t/ha.
When plants are grown under saline conditions, photosynthetic activity decreases leading to
reduced chlorophyll content and chlorophyll fluorescence reported by Muhammad et al. (2007).
Ali et al. (2004) also showed that the chlorophyll concentrations was reduced by salinity.
4.7. Dry matter production in different plant parts
4.7.1 Leaf dry matter
Leaf dry matter weight/ plant was reduced due to salinity (Fig. 6). The lowest leaf dry mass (1.97
g) was recorded at 100 mM salt condition. Organic amendment significantly increased leaf dry
matter of soybean under control and saline conditions. Highest leaf dry matter (7.11 g) was
observed when biochar was added @ 5 t/ha and it was 6.32g when compost was added @ 10 t/ha
under control condition. At 50 mM salinity condition, highest leaf dry matter (4.57 g) was

obtained from compost @ 5 t/ha and lowest leaf dry matter (3.9 g) was observed when compost
was applied @ 10 t/ha. At 100 mM saline condition, highest leaf dry matter (2.69 g) was
obtained when soil was treated with biochar @ 10 t/ha and it was lowest (2.43 g) when compost
was added in the soil @ 10t/ha. Organic amendment increase plant dry weight observed in a
variety of plants by numerous authors (Idrees et al., 2004; Abou El-Magd et al., 2008; Leithy et
al., 2010; Raafat and Thawrat, 2011). Dry weight of stem, leaves and whole plant showed
approximately decrease with salinity observed by Hussein et al. (2007).
4.7.2 Stem dry matter
Stem dry matter/ plant of soybean was reduced due to salinity and reduction was higher with
increasing salinity levels (Fig. 7). The lowest stem dry mass (2.02 g) was recorded at 100 mM
salt condition. At every case of compost and biochar treatment the stem dry mass was increasing
compare to normal condition. Highest stem dry matter (6.18 g) was observed when biochar was
added @ 5 t/ha and the lowest value (5.40 g) was recorded when compost was added @ 5 t/ha
under control condition. At 50 mM salinity condition highest stem dry matter (4.70 g) was
obtained from biochar @ 5 t/ha and the lowest stem dry matter (4.21 g) was observed when
compost was applied @ 5 t/ha. Under 100 mM saline condition highest stem dry matter (2.69 g)
was obtained when soil was treated with compost @ 5 t/ha and it was lowest (2.28 g) when
biochar was added in the soil @ 10 t/ha. Reduction in stem dry matter due to salinity as
compared to control was reported earlier by Karim et al. (1992) in triticale. At each salinity
level, incorporation of biochar increased shoot biomass, root length and volume reported by
Akhtar et al. (2015).

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
Treatments
Leaf dry weight (g/plant)
Fig. 6. Effect of organic amendments on leaf dry weight under saline conditions. Bars
indicate SE (±).
4.7.3 Root dry matter
Experimental results revealed that root dry matter was significantly affected by salinity (Fig. 8).
The lowest root dry mass (0.50 g) was recorded at 100 mM salt condition. Organic amendment
significantly increased root dry matter of soybean under control and saline conditions. Highest
root dry matter (2.53 g) was observed when biochar was added @ 5 t/ha and the lowest (2.17 g)
was obtained when compost was added @ 10 t/ha under control condition. At 50 mM salinity
condition highest root dry matter (1.70 g) was obtained from biochar @ 5 t/ha and lowest root
dry matter (1.37 g) was observed when compost was applied @ 5 t/ha. At 100 mM saline
condition highest root dry matter (0.90 g) was obtained when soil was treated with compost @ 5
t/ha and it was lowest (0.77 g) when biochar as well as compost were added in the soil @ 10 t/ha.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
Treatments
Stem dry weight (g/plant)
Fig. 7. Effect of organic amendments on stem dry weight under saline conditions. Bars
indicate SE (±).
Salinity induced root mass reduction was reported earlier by Ali et al. (2005) in sesame, Raptan
et al. (2001) and Sultana et al. (2007) in mungbean.
4.7.4 Shoot dry matter
The shoot dry weight is defined as the sum total of leaf, stem, and petiole dry weight. Shoot dry
matter was negatively affecting by increasing salinity level (Fig. 9). The lowest shoot dry mass
(3.99 g) was recorded at 100 mM salt condition. Organic amendment significantly increased
shoot dry matter of soybean under control and saline conditions. Highest shoot dry matter (13.30
g) was observed when biochar was added @ 5 t/ha and it was 11.71 g when biochar was added
@ 10 t/ha under control condition. At 50 mM salinity condition highest shoot dry matter (8.93 g)
was obtained from biochar @ 5 t/ha and lowest shoot dry matter (8.08 g) was observed when
compost was applied @ 10 t/ha.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
0.50
1.00
1.50
2.00
2.50
3.00
Treatments
Root dry weight (g/plant)
Fig. 8. Effect of organic amendments on root dry weight under saline conditions. Bars
indicate SE (±).
Under 100 mM saline condition highest shoot dry matter (5.26 g) was obtained when soil was
treated with compost @ 5 t/ha and the lowest (4.97 g) was observed when biochar as well as
compost were added in the soil @ 10 t/ha. Reduction in shoot dry weight due to salinity as
compared to control was reported by Sultana et al. (2007) in six mungbean varieties. Increasing
salinity level resulted in significant reductions of shoot biomass, root length and volume. At each
salinity level, incorporation of biochar increased shoot biomass, root length and volume observed
by Akhtar et al. (2015).
4.7.5 Total dry matter
Reduction in total dry matter production under saline condition and the positive effect of organic
amendment on total dry matter production are present in Fig. 10. Both 50 mM and 100 mM
salinity affect significantly on the total dry matter production in soybean plant.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
Treatments
Shoot dry weight (g)
Fig. 9. Effect of organic amendments on shoot dry weight under saline conditions. Bars
indicate SE (±).
Total dry matter of plant was decreased with the increase of soil salinity and the highest (4.36 g)
reduction occurred at 100 mM salt level. Organic amendment significantly increased total dry
matter of soybean under control and saline conditions. Highest total dry matter (15.66 g) was
observed when biochar was added @ 5 t/ha and the lowest (13.94 g) value was obtained when
biochar was added @ 10 t/ha under control condition. At 50 mM salinity condition highest total
dry matter (10.53 g) was obtained from biochar @ 5 t/ha and the lowest total dry matter (9.72 g)
was observed when compost was applied @ 10 t/ha. Under 100 mM saline condition highest
total dry matter (6.16 g) was obtained when soil was treated with compost @ 5 t/ha and it was
lowest (5.46 g) when biochar was added in the soil @ 5 t/ha.

Control
50 mM sea water
100 mM sea water
Control x 5 t/ha compost
Control x 10 t/ha compost
50 mM sea water x 5 t/ha compost
50 mM sea water x 10 t/ha compost
100 mM sea water x 5 t/ha compost
100 mM sea water x 10 t/ha compost
Control x 5 t/ha biochar
Control x 10 t/ha biochar
50 mM sea water x 5 t/ha biochar
50 mM sea water x 10 t/ha biochar
100 mM sea water x 5 t/ha biochar
100 mM sea water x 10 t/ha biochar
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
Treatments
Total dry weight (g)
Fig. 10. Effect of organic amendments on total dry matter weight under saline conditions.
Bars indicate SE (±).
Similar results have been observed in a variety of plants by numerous authors (Idrees et al.,
2004; Abou El-Magd et al., 2008; Leithy et al., 2010; Raafat and Thawrat, 2011). Reduction in
total dry matter production under salinity was also reported by Gill (1988), Patil et al. (1992) and
Raptan et al. (2001) in mungbean.
4.9. Yield and yield contributing characters
4.9.1 Number of pod
Soybean plants exposed to salinity caused a significant reduction in number of pod/plant (Table
3). Organic amendments with water hyacinth compost and rice husk biochar increased at 50 mM
and 100 mM salinity stress. The lowest number of pod/plant was found at 100 mM salinity level
(16). But due to organic amendment the number of pod/plant was increased as compare to the
control. Highest number of pod/plant (51) was observed when biochar was added @ 5 t/ha and

the lowest (33.67) was observed when compost was added @ 10 t/ha under control condition. At
50 mM salinity condition highest number of pod/plant (35.33) was obtained from biochar @ 5
t/ha and lowest number of pod/plant (27.67) was observed when compost was applied @ 5 t/ha.
Under 100 mM saline condition highest number of pod/plant (22.67) was obtained when soil was
treated with compost @ 5 t/ha and the lowest number of pod/plant (20.33) was recorded when
biochar as well as compost were added in the soil @ 10 t/ha. Similar result was found by Leithy
et al. (2010) on peanut at different levels of salinity. Haq et al. (2001) reported that combined
application of gypsum, pressmud and FYM produced the maximum number of effective tillers in
a saline-sodic soil.
4.9.2 Number of seed
The number of seed/pod also hampered by salinity stress in soybean plant (Table 3). This rate of
reduction was increasing with the increasing of salinity stress. Application of compost and
biochar (5 and 10 t/ha) significantly increased the number of seed/pod in soybean at 0 mM, 50
mM and 100 mM salinity stress. The lowest number of seed/pod (0.8) was observed at 100 mM
salinity level. But due to organic amendment the number of seed/pod was increased than control.
The highest number of seed/pod (2.17) was observed when biochar was added @ 5 t/ha and the
lowest (1.84) was obtained when compost was added @ 10 t/ha under control condition. At 50
mM salinity condition highest number of seed/pod (1.80) was obtained from biochar @ 5 t/ha
and lowest number of seed/pod (1.27) was observed when compost was applied @ 10 t/ha.
Under 100 mM saline condition highest number of seed/pod (1.31) was obtained when soil was
treated with biochar @ 5 t/ha and it was lowest (1.05) when compost was added in the soil @ 10
t/ha.

Table 3. Effect of organic amendments on number of pod/plant and number of seed/pod of
soybean under saline conditions
Similar result was also found by Leithy et al. (2010) on peanut at different levels of salinity.
Abou El-Magd et al. (2008) on sweet funnel, Raafat and Thawrat (2011) and Shazia et al. (2004)
on sugarcane also showed that organic amendments increased the number of grains per cob on
different salt stress condition. Surface mulching with compost has shown to reduce evaporation
and decrease salinity hazards to improve wheat production (Yeboah et al., 2009). Biochar has
been reported to significantly increase grain per plant and plant productivity (Glaser et al., 2002).
4.9.3 100- seed weight
Treatments Number of pod/plant Number of seed/pod
Control 33.33 1.43
50 mM sea water 25 1.17
100 mM sea water 16 0.80
Control × 5 t/ha compost 37 1.96
Control × 10 t/ha compost 33.67 1.84
50 mM sea water × 5 t/ha compost 27.67 1.40
50 mM sea water × 10 t/ha compost 32 1.27
100 mM sea water × 5 t/ha compost 22.67 1.17
100 mM sea water × 10 t/ha compost 20.33 1.05
Control × 5 t/ha biochar 51 2.17
Control × 10 t/ha biochar 46 2.02
50 mM sea water × 5 t/ha biochar 35.33 1.80
50 mM sea water × 10 t/ha biochar 32.33 1.71
100 mM sea water × 5 t/ha biochar 21.67 1.31
100 mM sea water × 10 t/ha biochar 20.33 1.17
LSD (5%) 3.92 0.2
CV (%) 7.8 8.2

Salt stress caused a significant decrease in 100- seed weight of soybean plant (Table 4). Organic
amendments with both compost and biochar significantly increased the 100-seed weight of
soybean at o mM, 50 mM and 100 mM salinity stress conditions. Highest 100-seed weight (14.9
g) was observed when biochar was added @ 5 t/ha and the lowest 100-seed weight (13.86 g) was
obtained when compost was added @ 5 t/ha under control condition. At 50 mM salinity
condition highest 100-seed weight (12.40 g) was obtained from biochar @ 5 t/ha and lowest 100-
seed weight (11.20 g) was observed when compost was applied @ 5 t/ha. Under 100 mM saline
condition, highest 100-grain weight (11.2) was obtained when soil was treated with compost @ 5
t/ha and it was lowest (9.67) when biochar was added in the soil @ 5 t/ha. Research findings of
many other researcher illustrated that salinity induced a marked reduction in yield attributes like
pod per plant and 1000 seed weight and seed yield. Islam et al. (2006), Abou El-Magd et al.
(2008) on sweet funnel, Raafat and Thawrat (2011) and Shazia et al. (2004) on sugarcane also
showed that organic amendments increased 100 grains weight on different salt stress condition.
Surface mulching with compost has shown decrease salinity hazards to improve wheat
production (Yeboah et al., 2009).
4.9.4 Yield
Salt stress caused a significant decrease in yield of soybean plant (Table 4). Organic amendments
with both compost and biochar significantly increased the yield of soybean at 0 mM, 50 mM and
100 mM salinity stress conditions. Under 50 mM salinity stress, both compost and biochar also
showed a considerable yield in soybean plant. At 50 mM salinity stress yield was higher at 10
t/ha than 5 t/ha compost treatment but at 100 mM salt level the increment of yield occurred at 5
t/ha compost treatment. In case of biochar, at 0 mM, 50 mM and 100 mM salt condition yield
was higher at 5 t/ha than 10 t/ha.

Table 4. Effect of organic amendments on 100-seed weight and yield of soybean under
saline conditions
Treatments 100- seed weight (g) Yield (g/plant)
Control 13.1 6.18
50 mM sea water 10.4 2.94
100 mM sea water 8.9 1.16
Control × 5 t/ha compost 13.9 11.42
Control × 10 t/ha compost 14.30 9.41
50 mM sea water × 5 t/ha compost 11.2 4.79
50 mM sea water × 10 t/ha compost 12.2 4.87
100 mM sea water × 5 t/ha compost 11.2 2.95
100 mM sea water × 10 t/ha compost 10.4 2.19
Control × 5 t/ha biochar 14.9 15.65
Control × 10 t/ha biochar 14.5 13.33
50 mM sea water × 5 t/ha biochar 12.4 8.63
50 mM sea water × 10 t/ha biochar 12.1 7.54
100 mM sea water × 5 t/ha biochar 9.7 2.74
100 mM sea water × 10 t/ha biochar 10.3 2.61
LSD (5%) 0.68 2.15
CV (%) 3.4 20.1
Highest yield (15.65 g) was observed when biochar was added @ 5 t/ha and the lowest (9.41 g)
yield was observed when compost was added @ 10 t/ha under control condition. At 50 mM
salinity condition highest yield (8.63 g) was obtained from biochar @ 5 t/ha and the lowest yield
(4.79 g) was observed when compost was applied @ 5 t/ha. Under 100 mM saline condition
highest yield (2.95 g) was obtained when soil was treated with compost @ 5 t/ha and it was
lowest (2.19 g) when compost was added in the soil @ 10 t/ha. Shazia et al. (2004) on sugarcane
also showed that organic amendments increased the yield of soybean on different salt stress
condition. At salinity level, biochar increased tuber yield reported by Khattak et al. (2007).
Organic mulching has been used to obtain good vegetable growth and yield in crops like sweet

potato, potato, tomato and pepper (Rahman et al., 2003). Application of only biogas slurry or
vermicompost enhanced the vegetative and reproductive yield of sunflower but the highest yield
was recorded in combined treatment of the both was reported by Ahmed et al. (2009). The
sustainable cane and sugar yields with good quality juice can be obtained by applying
gypsum/FYM or both under sodic and only FYM under saline-sodic water irrigation. Amanullah
(2008) showed that among the reclamation practices of coastal saline soils, FYM recorded better
growth, yield parameters, yield and nutrient uptake by rice crop.
4.10. Mineral ions accumulation in different plant parts of soybean
4.10.1 Concentration of Na, K, Ca, Mg and Na: K ratio in leaf
Leaf was taken into account for estimation of concentration of Na, K, Ca, Mg and Na: K ratio.
There was variation in accumulation of these elements in leaf of soybean plant due to different
salinity levels (Table 5). Salinity significantly increase the concentration of Na and Na: K ratio in
leaf of the soybean, while that of K and Ca decreased with increasing salinity levels. Organic
amendments with both compost and biochar significantly decreased Na and Na: K ratio of
soybean as well as increased the K, Ca, and Mg in leaf of soybean plant at 0 mM, 50 mM and
100 mM salinity stress conditions. At control condition, the lowest Na (0.63%) was found when
soil was treated with biochar @ 5 t/ha and the highest rate (0.69%) was obtained when compost
was added in the soil @ 5 t/ha and the lowest Na: K (0.48) ratio was found when soil was treated
with biochar @ 5 t/ha and the highest rate was (0.63) observed when compost was added in the
soil @ 5 t/ha. At 50 mM salt condition, lowest Na (0.75%) was found when soil was treated with
biochar @ 5 t/ha as well as compost @ 10 t/ha and the highest rate was (0.79%) obtained when
biochar was added in the soil @ 10 t/ha and lowest Na: K (0.68) ratio was found when soil was
treated with biochar @ 5 t/ha and it was highest (0.94) when compost was added in the soil @ 5

t/ha. On the other hand under 100 mM salinity stress condition lowest Na (0.81%) was found
when soil was treated with compost @ 10 t/ha and it was highest (0.84%) when biochar was
added in the soil @ 10 t/ha and lowest Na: K (0.91) ratio was found when soil was treated with
biochar @ 5 t/ha and it was highest (1.07) when compost was added in the soil @ 5 t/ha.
Application of 5 t/ha biochar performed the best among the organic amendments. At control
condition, highest K (1.29%), Ca (2.43%), Mg (0.67%) was found when soil was treated with
biochar @ 5 t/ha and the lowest K (1.08%), Ca (2.07%), Mg (0.58%) when compost was added in
the soil @ 10 t/ha, 5 t/ha and both 5 t/ha as well as 10 t/ha respectively. At 50 mM salt condition
highest K (1.11%), Ca (1.7%), Mg (0.59%) was found when soil was treated with biochar @ 5
t/ha, 10 t/ha, 5 t/ha respectively and the lowest K (0.82%), Ca (1.27%), Mg (0.52%) when
compost was added in the soil @ 10 t/ha. At 100 mM salt stress condition highest K (0.91%), Ca
(1.07%), Mg (0.48%) was found when soil was treated with biochar @ 5 t/ha, 5 t/ha and 10 t/ha
respectively and the lowest K (0.76%), Ca (0.95%), Mg (0.44%) when compost was added in the
soil @ 5 t/ha, 10 t/ha and 5 t/ha respectively. The compost and manure increased markedly the
shoot growth, this seemed to be related to decreases in the shoot concentrations of Na and Cl and
increases in K (David et al., 2008). Conversely Leithy et al. (2010) found that organic
amendments did not show any changes of nutrient content except Na. Organic manures have
been shown to increase K/Na ratio in sweet fennel (Abou El-Magd et al., 2008). Biochar can
increase nutrient content and improved retention of nutrients (Lehmann et al., 2003; Wardle et
al., 1998); Amanullah (2008) showed in rice crop.
Table 5. Effect of organic amendments on concentration of Na, K, Ca, Mg and Na: K ratio
in leaf of soybean under saline conditions

Treatments Na (%) K (%) Ca (%) Mg (%) Na:K
ratio
Control 0.71 1.03 1.15 0.54 0.68
50 mM sea water 0.83 0.73 1.07 0.50 1.14
100 mM sea water 0.90 0.62 0.86 0.40 1.44
Control × 5 t/ha compost 0.69 1.09 2.07 0.58 0.63
Control × 10 t/ha compost 0.67 1.08 2.27 0.58 0.62
50 mM sea water × 5 t/ha compost 0.78 0.83 1.43 0.54 0.94
50 mM sea water × 10 t/ha compost 0.75 0.82 1.27 0.52 0.91
100 mM sea water × 5 t/ha compost 0.82 0.76 1.06 0.44 1.07
100 mM sea water × 10 t/ha compost 0.81 0.78 0.95 0.47 1.04
Control × 5 t/ha biochar 0.63 1.29 2.43 0.67 0.48
Control × 10 t/ha biochar 0.66 1.16 2.23 0.63 0.57
50 mM sea water × 5 t/ha biochar 0.75 1.11 1.63 0.59 0.68
50 mM sea water × 10 t/ha biochar 0.79 1.09 1.70 0.57 0.73
100 mM sea water × 5 t/ha biochar 0.83 0.91 1.07 0.44 0.91
100 mM sea water × 10 t/ha biochar 0.84 0.85 1.06 0.48 0.99
LSD (5%) 0.29 0.57 0.15 0.36 0.60
CV (%) 2.3 3.7 6.1 4.0 4.2
4.10.2 Concentration of Na, K, Ca, Mg and Na: K ratio in stem
Plant parts such as stem, leaf and root were taken into account for estimation of concentration of
Na, K, Ca, Mg and Na: K ratio. There was variation in accumulation of these elements in stem of
soybean plant due to different salinity levels (Table 6). The concentration of Na in stem of the
soybean increased, while that of K, Ca and Mg decreased with increasing salinity levels. Organic
amendments with both compost and biochar significantly decrease Na and Na: K ratio of
soybean as well as increase the K, Ca, Mg in stem of soybean plant at 0 mM, 50 mM and 100
mM salinity stress conditions. At control condition lowest Na (0.60%) was found when soil was
treated with biochar @ 5 t/ha and it was highest (0.67%) when compost was added in the soil @
10 t/ha and lowest Na: K (0.48) ratio was found when soil was treated with biochar @ 5 t/ha and

it was highest (0.64) when compost was added in the soil @ 10 t/ha. At 50 mM salt condition
lowest Na (0.75%) was found when soil was treated with compost @ 10 t/ha and it was highest
(0.87%) when biochar was added in the soil @ 10 t/ha and lowest Na: K (0.71) ratio was found
when soil was treated with biochar @ 5 t/ha and it was highest (0.82) when biochar was added in
the soil @ 10 t/ha. On the other hand under 100 mM salinity stress condition, lowest Na (0.86%)
was found when soil was treated with biochar @ 10 t/ha and it was highest (0.97%) when
compost was added in the soil @ 10 t/ha and lowest Na: K (0.90) ratio was found when soil was
treated with both biochar @ 10 t/ha and 10 t/ha compost, whereas, the highest ratio (1.07) was
found when compost was added in the soil @ 10 t/ha. At control condition, highest K (1.24%),
Ca (1.07%), Mg (0.86%) were found when soil was treated with biochar @ 5 t/ha and the lowest
K (1.05%), Ca (0.86%), Mg (0.46%) were obtained when compost was added in the soil @ 10
t/ha and 5 t/ha, respectively. At 50 mM salt condition, highest K (1.15%), Ca (0.92%), Mg
(0.62%) were found when soil was treated with biochar @ 5 t/ha, 10 t/h and 5 t/ha, respectively
and the lowest K (0.98%), Ca (0.71%), Mg (0.55%) when compost was added in the soil @ 5
t/ha, 10 t/ha and 10 t/ha respectively. At 100 mM salt stress condition, highest K (1.0%), Ca
(0.55%), Mg (0.53%) was found when soil was treated with biochar @ 5 t/ha, 10 t/ha and
compost @ 5 t/ha, respectively and the lowest K (0.91%) ,Ca (0.44%) @ 10 t/ha compost and Mg
(0.42%) when biochar was added in the soil @ 5 t/ha, respectively.
Table 6. Effect of organic amendments on concentration of Na, K, Ca, Mg and Na: K ratio
in stem of soybean under saline conditions
Treatments Na (%) K (%) Ca (%) Mg (%) Na:K
ratio
Control 0.67 1.11 0.69 0.43 0.60

50 mM sea water 0.89 0.99 0.63 0.41 0.91
100 mM sea water 1.06 0.84 0.38 0.37 1.28
Control × 5 t/ha compost 0.64 1.14 0.90 0.46 0.57
Control × 10 t/ha compost 0.67 1.05 0.86 0.57 0.64
50 mM sea water × 5 t/ha compost 0.76 0.98 0.82 0.56 0.79
50 mM sea water × 10 t/ha compost 0.75 1.06 0.71 0.55 0.71
100 mM sea water × 5 t/ha compost 0.95 0.92 0.45 0.53 1.03
100 mM sea water × 10 t/ha compost 0.97 0.91 0.44 0.48 1.07
Control × 5 t/ha biochar 0.60 1.24 1.07 0.86 0.48
Control × 10 t/ha biochar 0.62 1.19 0.99 0.79 0.52
50 mM sea water × 5 t/ha biochar 0.82 1.15 0.87 0.62 0.71
50 mM sea water × 10 t/ha biochar 0.87 1.06 0.92 0.59 0.82
100 mM sea water × 5 t/ha biochar 0.93 1.0 0.46 0.42 0.93
100 mM sea water × 10 t/ha biochar 0.86 0.96 0.55 0.45 0.90
LSD (5%) 0.38 0.71 0.34 0.32 0.75
CV (%) 2.9 4.1 2.9 3.6 5.6
Incorporation of organic materials for reducing deleterious effects of saline water was reported
by many scientists (Minhas et al., 1995; Choudhary et al., 2002). In relation to the application of
compost and its benefits, researchers (Graber et al., 2010, Zhang et al., 2012) confirm that
biochar can be also an important tool to increase Ca, K and Mg in soybean plants.

CHAPTER V
SUMMARY
A pot experiment was carried out at the Department of Agronomy, Bangabandhu Sheikh Mujibur
Rahman Agricultural University, Gazipur from November 2015 to March 2016 to investigate the
effect of organic amendments to mitigate salinity stress on soybean variety BARI soybean 5.
Two types of organic amendments i. water hyacinth compost ii. rice husk biochar were used in
soil @ of 5 t/ha and 10 t/ha of both. Saline solution was prepared by adding tap water in sea
water to make 50 and 100 mM salinity level equivalent to 5 and 10 dS/m, respectively. Plants
were irrigated with 50 and 100 mM saline solution from 14th days after sowing (DAS) to maturity
and control plants were irrigated with tap water. The treatments of the experiment were: i.
Control ii. 50 mM sea water iii.100 mM sea water iv. Control × 5 t/ha compost v. Control ×10
t/ha compost vi. 50 mM sea water × 5 t/ha compost vii. 50 mM sea water × 10 t/ha compost viii.
100 mM sea water × 5 t/ha compost ix. 100 mM sea water × 10 t/ha compost x. Control × 5 t/ha

biochar xi. Control × 10 t/ha biochar xii. 50 mM sea water × 5 t/ha biochar xiii. 50 mM sea water
× 10 t/ha biochar xiv. 100 mM sea water × 5 t/ha biochar xv. 100 mM sea water × 10 t/ha
biochar. Data on different physiological parameters like exudation rate, relative water content
(RWC), water retention capacity (WRC), water uptake capacity (WUC) and Chlorophyll content
were measured at flowering stage. Plant height, dry weight of different plant parts, yield and
yield contributing characters as well as Na, K, Ca, Mg and Na: K ratio in leaf and stem were
recorded at harvest. Results revealed that salinity decreased plant height and highest reduction
was found at 100 mM salinity level. Organic amendments increased plant height under control
and saline conditions. Water hyacinth compost @ 10 t/ha was the most effective treatment in
enhancing plant height under 50 mM salinity stress. Exudation rate of soybean plant was reduced
significantly at salinity stress. Highest exudation rate was found when soil was treated with 5 t/ha
compost at 50 mM saline condition. Salinity stresses remarkably affects relative water content
(RWC), water retention capacity (WRC) in BARI soybean-5. On the other hand, both biochar
and compost resulted in a significant increase RWC, WRC in soybean plant. Highest relative
water content was found when soil was treated with 5 t/ha compost at 50 mM saline condition
but maximum WRC was observed when soil was treated with rice husk biochar @ 5 t/ha under
50 mM salinity. Salinity increased water uptake capacity (WUC) in soybean plant. Water
hyacinth compost and rice husk biochar decreased water uptake capacity under saline conditions.
At 50 mM saline condition lowest WUC was found when soil was treated with 10 t/ha rice husk
biochar. Highest chlorophyll a was obtained from biochar @ 5 t/ha under 50 mM salinity level
and highest chlorophyll b was observed in treatment @ 10 t/ha biochar under same salinity level.
But highest total chlorophyll was obtained from compost @ 5 t/ha under 50 mM salinity level.
Highest leaf dry matter was obtained from compost @ 5 t/ha at 50 mM salinity condition on the

other hand highest stem, root, shoot and toatl dry matter were obtained from treatment 5 t/ha rice
husk biochar under 50 mM salinity stress. Highest number of pod/plant, number of seed/pod,
100-seed wight and seed yield/plant were recorded from rice husk biochar @ 5 t/ha at 50 mM
salinity level. In leaf lowest concentration of Na and highest concentration of K, Ca and Mg were
found in treatment 5 t/ha biochr at 50 mM salinity level. But in stem lowest concentration of Na
was obtained from @ 10 t/ha compost under 50 mM salinity and highest K and Mg were
observed in 5 t/ha biochar under same salinity level.
CHAPTER VI
CONCLUSION
From the results it could be concluded that
Salinity decreased plant height, exudation rate, relative water content, water retention
capacity, chlorophyll content, dry matter production and yield but increased water uptake
capacity of soybean plant.
Application of water hyacinth compost and rice husk biochar were found to mitigate the
negative effects of salinity stress at low salinity level (50 mM) but did not show
appreciable performance to alleviate the adverse effect of salinity at high saline
conditions (100 mM).
Among the organic amendments used rice husk biochar @ 5 t/ha showed better
mitigating effect than water hyacinth compost.

Therefore, salinity induced reduction in the plant growth, physiology and yield of
soybean could be mitigated by application of organic amendments in soil under low
salinity stress.
REFERENCES
Abdullah, Z., M. A. Khan and T. J. Flowers. 2001. Causes of sterility in seed set of rice under
salinity stress. Journal of Agronomy and Crop Science. 187(1): 25-32.
Abou El-Magd, M. M., M. F. Zaki and S. D. Abou-Hussein. 2008. Effect of organic manure and
different levels of saline irrigation water on growth, green yield and chemical content of
sweet fennel. Australian J. of Basic and Applied Sci. 2(1): 90-98.
Ahmad, R. and J. Nusrat. 2009. Vegetative growth and yield of tomato as affected by the
application of organic mulch and gypsum under saline rhizosphere. Pak. J. Bot., 41(6):
3093-3105.
Ahmadullah, M., B. H. Niazi and G. R. Sandhu. 2008. Effectiveness of gypsum, HCL and
organic matter for the improvement of saline sodic soils. Pak J. Agric. Res. 9(3): 373-
378.

Aisha, S., S. Mumtaz, S. Raza, M. A. Khan and S. Solangi. 2005. Salinity effects on seedling
growth and yield components of different inbred rice lines. J. Bot. 37(1): 131-139.
Akhtar, S. S., N. A., Mathias, N. Muhammad, A. Z. Zahir and L. Fulai. 2015. Interactive effect
of biochar and plant growth-promoting bacterial endophytes on ameliorating salinity
stress in maize. Functional Pl. Biology. 42: 770–781.
Ali, M. A., M. T. Islam and M. T. Islam. 2005. Effect of salinity on some morphophysiological
characters and yield in three seasame cultivars. J. Bangladesh Agric. Univ. 3: 209-214.
Ali, Y., Z. Aslam and M. Y. Ashraf. 2004. Effect of salinity on chlorophyll concentration, leaf
area, yield and yield components of rice genotypes grown under saline environment. Int.
J. of Envi. Sci. & Tech. 1(3): 221–225.
Anjum, S. A., Xie, X., Wang, L., Saleem, M. F., Man, C. and Lei, W. 2011. Morphological,
physiological and biochemical responses of plants to drought stress. African Journal of
Agricultural Research. 6(9): 2026-2032.
Anonymous, 2012.en.wikipedia/wiki/soybean @ google.com
Asai, H., B. K. Samson, H. M. Stephan, K. Songyikhangsuthor, K. Homma, Y. Kiyono, Y. Inoue,
T. Shiraiwa and T. Horie. 2009. Biochar amendment techniques for upland rice
production in Northern Laos 1. Soil physical properties, leaf SPAD and grain yield. Field
Cr. Resh. 111: 81-84.
Ashraf, M. 1989. The effect of Salinity on water relations, chlorophyll, and protein and proline
contents of two cultivars of blackgram (Vigna mungo L.). P. & Soil. 119(2): 205-210.
Ashraf, M., S. Hasnain, O. Berge and T. Mahmood. 2004. Inoculating wheat seedlings with
exopolysaccharide-producing bacteria restricts sodium uptake and stimulates plant
growth under salt stress. Bio. & Fertility of Soi. 40: 157–162.

Babu and Thirmurugan. 2001. Rice can acclimate to lethal level of salinity by pretreatment with
sub lethal level of salinity through osmotic adjustment. Pl. and Soil. 284(1/2): 56-59.
Balasubramania, V. and S. Rao. 1977. Physiological basis of salt tolerance in rice. Riso. J. 26:
291-294.
Bernstein, L. 1975. Effects of salinity and sodicity on plant growth. Annu. Rev. Phytopathol., 13:
295-312.
Blackwell, P., E. Krull, G. Butler, A. Herbert and Z. Solaiman. 2010. Effect of banded biochar on
dryland wheat production and fertiliser use in south-western Australia: an agronomic and
economic perspective. Aust. J. Soil Res. 48: 531–545.
Burman, U., B. Garg and K. S. Kathju. 2002. Interactive effect of saline water irrigation and
nitrogen fertilization on growth and metabolism of rice. J. Plant Biol. 29: 249-255.
Carvalho, M. T., A. H. N. Maia, B. E. Madari, L. Bastiaans, P. A. J. Oort, A. B. Heinemann, M.
A. S. Silva, F. A. Petter, B. H. J. Marimon and H. Meinke. 2014. Biochar increases plant-
available water in a sandy loam soil under an aerobic rice crop system. Solid Earth. 5:
939–952.
Case, S. J., N. P. McNamara, D. S. Reay and J. Whitaker. 2012. The effect of biochar addition on
N2O and CO2 emissions from a sandy loam soil—The role of soil aeration. Soil Biol.
Biochem. 51: 125–134.
Chan, K. Y., L. V. Zwieten, I. Meszaros, A. Downie and S. Joseph. 2007. Agronomic values of
greenwaste biochar as a soil amendment. Austr. J. Soil Res. 45: 629–634.

Chan, K. Y., L. V. Zwieten, I. Meszaros, A. Downie and S. Joseph. 2008. Using poultry litter
biochars as soil amendments. Austral. J. Soil Res. 46:437–444.
Chan, K.Y. and Z. Xu. 2009. Biochar: nutrient properties and their enhancement. In: Lehmann,
J., Joseph, S. (Eds.), Biochar for Environmental Management: Science and Technology.
Earthscan, London. 67–84.
Cha-um, S., P. Vejehasarn and C. Kirdmanee. 2007. An effective defensive response in Thai
aromatic rice varieties (Oryza sativa L. spp. indica) to salinity. J. Crop Sci. Biotech.
10(4): 257-264.
Choudhary, O. P., A. S. Josan and M. S. Bajwa. 2002. Role of organic materials in mobilizing
intrinsic calcium carbonate to ameliorate sodic irrigations. In: Proceedings of the 17th
World Congress Soc. Sci. 34(3): 22–36.
Cordovilla, M. P., A. Ocana, F. Ligero and C. Lluch. 1995. Growth and macronutrient contents of
faba bean plants: Effects salinity and nitrate nutrition. J. Plant Nutr. 18:1611-1628.
Debnath S. C. 2003. Effect of salinity on growth and yield in three mustard 79 gnotypes. M.S
Thesis, Dept. Crop Bot., Bangladesh Agril. Univ., Mymensingh.
Debosz, K., S .B. O. Petersen, L. K. Kure and P. Ambus. 2002. Evaluating effects of sewage
sludge and household compost on soil physical, chemical and microbiological properties.
Appl. Soil Ec. 19: 237-248.
Delgado, M. J., F. Ligero and C. Lluch. 1994. Effects of salt stress on growth and nitrogen
fixation by pea, faba-bean, common bean and soybean plants. Soil Biol. Biochem. 26:
371-376.

Dogan, M. 2011. Antioxidative and proline potentials as a protective mechanism in soybean
plants under salinity stress. African J. of Biotech. 10(32): 5972-5978.
FAO. 2013. Land and Plant Nutrition Management Service. http://www.fao.org/ag/agl/agll
/spush.
Fathi, N. O. 2010. Impact of compost on the availability and nutrients content of Vicia faba
grown on saline water-irrigated soil. Minu¯ya J. Agr. Res. 35(42): 1573-1585.
Gaballah, M. S. and M. S. Mandour. 1999. Increasing drought resistance of wheat plants during
grain filling byusing chemical desiccants.J. Sci. Mansoura Univ., 25(2): 833-841.
Gaskin J. W., R. A. Speir, K. Harris, K. C. Das, R. D. Lee, L. A. Morris and D. S. Fisher. 2010.
Effect of peanut hull and pine chip biochar on soil nutrients, corn nutrient status, and
yield. Agron J. 102:623–633.
Gill, K. S. 1988. Effect of saline water application on growth and yield at different growth stages
in mung [Vigna radiate (L) Wilezek]. Natio. Symp. Manage. Irrig. Sys. Pp. 24-27.
CSSRL, Karnal, India.
Glaser, B., J. Lehmann and W. Zech. 2002. Ameliorating physical and chemical properties of
highly weathered soils in the tropics with charcoal—a review. Bio. F. Soi. 35:219–230.
Gomez, A. A. and A. A. Gomez. 1984. Statistical procedure of agricultural Research. John Wiley
and Sons. New York. 20-2015.
Gopal and K.S. Dube. 2003. Influence of soil and foliar application of potassium on growth,
nutrient utilization, yield and quality of sugarcane (Saccharum officinarum L.). New
Botanist. 21(1-4): 13-20.

Graber, E. R., Y. M. Hare, M. Kolton, E. Cytryn, A. Silber, D. R. David, L. Tsechansky, M.
Borenshtein and Y. Elad. 2010. Biochar impact on development and productivity of
pepper and tomato grown in fertigated soilless media. Plant Soil. 337: 481–496.
Haefele, S., Y. Konboon, W. Wongboon, S. Amarante, A. Maarifat, E. Pfeiffer and C. Knoblauch.
2011. Effects and fate of biochar from rice residues in rice-based systems. Field Crops
Res. 121: 430–441.
Hajer, A. S., A. A. Malibari, H. S. Al-Zahrani, and O. A. Almaghrabi. 2006. Responses of three
tomato cultivars to sea water salinity 1. Effect of salinity on the seedling growth. Afri. J.
of Biotechnology. 5 (10): 855-861.
Hakim, M. A. 2003. Effect of salinity stress in two high yielding boro rice varieties and a hybrid.
M.S. Thesis, Department of Crop Botany. Bangladesh Agricultural University,
Mymensingh. 26-51.
Hanay, A., F. Büyüksönmez, F. M. Kiziloglu and M. Y. Canbolat. 2004. Reclamation of Saline-
Sodic Soils with Gypsum and MSW Compost. Com. Sei. Util., 12:175-179.
Haq, I., S. G. Khattak, H. Rahman, A. Ali, M. Salim. 2001. Effect of various amendments on
yield of rice crop under saline-sodic conditions in Mardan/Swabi districts. Inter. Jo. Agril.
Biol. 3: 289-291.
Hasanuzzaman, M., M. Fujita, M. N. Islam, K. U. Ahamed and K. Nahar. 2009. Performance of
four irrigated rice varieties under different levels of salinity stress. International J. of
Integrative Bio. 6(2): 85-90.

Helalia, A. M. and J. Letey. 1989. Effects of Different Polymers on Seedling Emergence,
Aggregate Stability and Crust Hardness. Soil Sci. 148(3): 199–203.
Hidetoshi A, S. K. Benjamin, S. M. Haefele, K. Songyikhangsuthor, K. Homma, Y. Kiyono, Y.
Inoue, T. Shiraiwa and T. Horie. 2009. Biochar amendment techniques for upland rice
production in Northern Laos 1. Soil physical properties, leaf SPAD and grain yield. Field
Crops Res. 111:81–84.
Hossain, M. M. 2006. Effect of salinity level on growth and yield of advanced mutant rice in
Boro season. M. S. Thesis, Dept. Crop Bot., Bangladesh Agril. Univ. Mymensingh.
Hussein, M. M., L. K. Balbaa and M. S. Gaballah. 2007. Salicylic acid and salinity effects on
growth of maize plants. Research Journal of Agriculture and Biological Sciences, 3(4):
321-328.
Idrees, S., M. S. Qureshi, M. Y. Ashraf, M. Hussain and N. H. Naveed. 2004. Influence of
sulphate of potash (Sop) and farmyard manure (Fym) on sugarcane (Saccharum
officinarum L.) grown under salt stress. Pak. J. Life Social Sci. 2(1): 65–69.
Islam, M. M. 2004. Effect of salinity on growth and yield of advanced mutant rice in boro
season. M. S. Thesis, Dept. Crop Bot., Bangladesh Agril. Univ. Mymensingh.
Islam, M. T., P. C. Sharma, R. K. Gautam, D. Singh, S. Singh, B. Panesar and S. Ali. 2011. Salt
tolerance in parental lines of rice hybrids through physiological attributes molecular
markers. Int. J. of Exp. Agri. 2(1) 1-7.

Islam, M.S. 2006. A baseline study on the groundwater quality of Magura and Thenaidah district.
M.S. Thesis. Department of Agricultural Chemistry, Bangladesh Agricultural University,
Mymensingh.
Jahan, A. H. 2006. Salinity tolerance in rice varieties at different growth stages. Aust. J. of Agri.
28: 343-349.
Jaleel, C. A., R. Gopi, P. Manivannan and R. Panneerselvam. 2007. Responses of antioxidant
defense system of Catharanthus roseus L. G. Don. to paclobutrazol treatment under
salinity. Acta. Physiologiae. Plantanirn. 29: 205-209.
Jeffery, S., F. G. A. Verheijen, M. van der, Velde and A. C. Bastos. 2011. A quantitative review of
the effects of biochar application to soils on crop productivity using meta-analysis. Agric.
Ecosyst. Environ. 144: 175–187.
Kabir, M. F. A. Hamid, M. M. Haque, E. Nawata and M. A. Karim. 2005. Effect of nitrogen
fertilizer on salinity tolerance of mungbean (Vigna radiate L. Wilczek). J. Crop Sci. 61
(3): 439-446.
Karim, M. A., M. A. E. Nawata and S. Shigenaga, 1992. Dry matter production and distribution
of mineral ions in different parts of plant in hexaploid triticale under salt stress condition.
Jap. J. Crop Sci. 61 (3):439-446.
Karmoker, J. l., F. Sharmin and R. Parveen, 2005. Effects of salinity on ion accumulation in
maize (zea mays l. cv. bari-7), Bangladesh j. bot. 37(2): 203-205.

Kamara A, S. K. Hawanatu and S. K. Mohamed. 2015. Effect of Rice Straw Biochar on Soil
Quality and the Early Growth and Biomass Yield of Two Rice Varieties, Agricultural
Sciences, 2015, 6, 798-806.
Khan, M. A., A. U. Irwin and M. S. Allan. 1999. Effects of salinity on growth, water relations
and ion accumulation of the subtropical perennial halophyte, atriplex griffithii var.
stocksii. Annals of Botany. 85(2): 225-232.
Khan, M. S. A., A. Harnid, A. B. M. Salahuddin, A. Quasem and M. A. Karim. 1997. Effect of
sodium chloride on growth, photosynthesis and mineral ions accumulation of different
types of rice. J. Agron. Crop Sci. 179: 149-161.
Khattak, S. G., I. Haq, U. Malik, A. Khattak and M. J. Naveedullah. 2007. Effect of various
levels of gypsum application on the reclamation of salt affected soil grown under rice
followed by wheat crop. Sarhad J. of Agri. 23: 675-680.
Kimetu J, J. Lehmann, S. Ngoze, D. Mugendi, J. Kinyangi, S. Riha, L. Verchot, J. Recha and A.
Pell. 2008. Reversibility of soil productivity decline with organic matter of differing
quality along a degradation gradient. Ecosystems. 11:726–739.
Komor, S. C. 1997. Boron contents and isotopic compositions of hog manure, selected fertilizers,
and water in Minnesota. J. Environ. Qual. 26: 1212-1222.
Laird, D. A., P. D. Fleming, D. D. Davis, R. Horton, B. Wang, D. L. Karlen. 2010. Impact of
biochar amendments on the quality of a typical Midwestern agricultural soil. Geoderma
in press: Geoderma doi:10.1016/j.geoderma.2010.1005.1013.

Lashari, M. S., Y. Ye, H. Ji, L. Li, G.W. Kibue, H. Lu, J. Zheng and G. Pan. 2013. Effects of
amendment of biochar-manure compost in conjunction with pyroligneous solution on soil
quality and wheat yield of a salt-stressed cropland from Central China Great Plain. Field
Crop Res. 144: 113–118.
Lashari, M. S., Y. Ye, H. Ji, L. Li, G.W. Kibue, H. Lu, J. Zheng and G. Pan. 2015. Biochar–
manure compost in conjunction with pyroligneous solution alleviated salt stress and
improved leaf bioactivity of maize in a saline soil from central China: a 2-year field
experiment. J. Sci. Food Agric. 95 (5): 1321–1327.
Lax, A., E. Diaz, V. Castillo and J. Albaladejo. 1994. Reclamation of physical and chemical
properties of a salinized soil by organic amendment. Arid Soil Res. Rehabil. 8: 9-17.
Lee, C. K., Y. H. Yoon, J. C. Shin, B. W. Lee and C. K. Kim. 2002. Growth and yield of rice as
affected by saline water treatment at different growth 82 stages. Korean J. Crop Sci. 47
(6): 402-408.
Lehmann, J. and S. Joseph. 2015. Biochar for environmental management: an introduction. In:
Lehmann, J., Joseph, S. (Eds.), Biochar for Environmental Management: Science and
Technology. Earthscan, London. 1–14.
Lehmann, J., D. Silva, J. P, J. Steiner, C. Nehls, T. Zech and B. Glaser. 2003. Nutrient availability
and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin:
fertilizer, manure and charcoal amendments. Plant &Soil. 249: 343–357.
Leithy, S., M. S. Gaballah and A. M. Gomaa. 2010. Associative impact of bio- and organic
fertilizers on geranium plants grown under saline conditions. Electron. J. Environ. Agric.
Food Chem. 9(3): 617-626.

Liang, B., J. Lehmann, D. Solomon, J. Kinyangi, J. Grossman, B. O’Neill, J. O. Skjemstad, J.
Thies, F.J. Luizão, J. Petersen and E.G. Neves. 2006. Black carbon increases cation
exchange capacity in soils. Soil Sci. Soc. Am. J. 70: 1719–1730.
Liang, Y., J. Si, M. Nikolic, Y. Peng, W. Chen and Y. Jiang. 2005. Organic manure stimulate
biological activity and barley growth in soil subject to secondary salinization, Soil Biol.
Biochem. 37: 1185-1195.
Linhe, Z., M. C. Shannon and L. H. Zeng. 2000. Salinity effects on seedling growth and yield
components of rice. Crop Sci. 40: 996-1003.
Lynch, D. H., R. P. Voroney and P. R. Warman. 2005. Soil physical properties and organic matter
fractions under forages receiving composts, manure or fertilizer. Compost Sei. Util., 13:
252-261.
Major J, M. Rondon, D. Molina, S. Riha and J. Lehmann. 2010. Maize yield and nutrition
during 4 years after biochar application to a Colombian savanna oxisol. Plant Soil
333:117–128.
Mansour, M. M. F. 2000. Nitrogen containing compounds and adaptation of plants to salinity
stress. Biol. Plant. 43: 491-500.
Mensah, J. K., P. A. Akomeah, B. Ikhajiagbe and E. O. Ekpekurede. 2006. Effect of salinity on
germination, growth and yield of five groundnut genotypes. Afr. J. Biotechnol., 5:1973-
1979.
Mia, S., M. Abuyusuf, M. A. Sattar, A. B. M. Islam, T. Hiemstra and S. Jeffery. 2015. Biochar
amendment for high nitrogen and phosphorous bio-availability and its potentiality of use
in Bangladesh Agriculture: a review. J Patuakhali Sci Technol Univ. 5: 145–156.

Miah. 1992. Salinity tolerance evaluation at the young stage of three new rice (Oryza sativa L.)
lines by morpho-agronomic markers. Cultivars Crop. 22(2): 58-62.
Minhas, P. S., D. R. Sharma and Y. P. Singh. 1995. Response to paddy and wheat to applied
gypsum and FYM on an alkali water irrigated soil. J. Indian Soc. Soil Sci. 43, 452–455.
Mortazainezhad, F., R. Khavarinejad and M. Emami. 2006. Study of some parameters of yield
and proline in rice plants under Salinity salinity stress. Journal New Agricultural Science
2(4): 93-98.
Muhammad, M., M. A. T. Chowdhury and I. Sarwar. 2007. Floristic condition and species
distribution in Sundarban mangrove forest community, Bangladesh. J. Bio. Sci. 7(2): 384-
388
Mulcahy, D. N. D. L. Mulcahy and D. Dietz. 2013. Biochar soil amendment increases tomato
seedling resistance to drought in sandy soils. J. Arid Environ. 81: 222–225.
Munns, R. 2002. Comparative physiology of salt and water stress. Plant Cell Environ. 25, 239–
250.
Nandwal, A. S. M., D. V. Godara, B. S. Kamboj, A. Kundu, B. K. Mann and K. P. Sharma. 2000.
Nodule functioning in pentafoliate mungbean genotypes as influenced by salinity. Biol.
Plant. 43: 459-462.
Noguera, D., M. Rond, K. R. Laossi, V. Hoyos, P. Lavelle and C. Carvalho. 2010. Contrasted
effect of biochar and earthworms on rice growth and resource allocation in different soils.
Soil Bio. & Biochemistry. 42: 1017–1027.

Papadopoulos, I., V. V. Rending and F. E. Broadbent. 1987. Growth, nutrition and water uptake
of tomato plants with divided roots growing in differentially salinized soil. Agron. J. 77:
21-26.
Patil, S. L., C. S. Hunsal, D. P. Viswanwth, V. P. Chimmad, V. S. Kubsad, S. B. Salimath and R.
M. Hosmani. 1992. Effect of saline water irrigation on soil properties, growth and yield
of greengram during summer. J. Maharastrra Agric. Univ. 17: 229-231.
Pessarakli, M. and T. C. Tucker. 1985. Uptake of nitrogen-15 by cotton under salt stress. Soil Sci.
Soc. Amer. J. 49:149-152.
Poway, S. L. and V. B. Mehta. 1997. Salt tolerance of different rice varieties under coastal saline
condition. Annals Agric. Res. 18: 536-538.
Prendergast-Miller, M. T., M. Duvall and S. P. Sohi. 2011. Localisation of nitrate in
therhizosphere of biochar-amended soils. Soil Bio. & Biochemistry. 43: 2243–2246.
Qadar, A. 1995. Requirement of rice crop for phosphorus and potassium at varying sodicity
levels. J. Plant Nut. 18 (11): 2291-2303.
Raafat, N. Z. and E. E. R. Tharwat. 2011. Improving wheat grain yield and its quality under
salinity conditions at a newly reclaimed soil using different organic sources as soil or
foliar applications. J. Applied Sci. Res. 7: 42-55.
Ragiba, M. 2000.Germination and seedling growth of seasame as affected by salinity. Annals of
Agricultural Res. 21:303-304.

Rahman, M. M. 2003. Effect of salinity stress on physiological features and yield in three
mustard genotypes. M.S Thesis, Dept. Crop Bot., Bangladesh Agricultural University,
Mymensingh.
Raptan, P. K., Hamid, A., Khaliq, Q. A., R. M. Solaiman, A. J. U. Ahmed and M. A. Karim,
2001. Salinity tolerance of balckgram and mungbean: II. Mineral ion accumulation in
different plant parts. Korean J. Crop Sci. 46: 380-394.
Rashid, A., R. H. Qurashi, P. A. Hilington and R. G. Wyne Jones. 2005. Comparative response of
wheat (Triticum aestivum L.) cultivars to salinity at seedlingstage. J. Agron. Crop Sci.
182:199-207.
Raychev, T., S. Popandova, G. Jozefaciuk, M. Hajnos and Z. Sokolowska. 2001.
Physicochemical reclamation of saline soils using coal powder. Int. Agrophys. 15: 51.
Reddy, N. and D. M. Crohn. 2012. Compost Induced Soil Salinity: A New Prediction Method
and Its Effect on Plant Growth. Compost Science & Utilization. 20(3):133-140.
Rymar, V. T., S. I. Ignatenko, I. V. Podlesnyi and N. M. Kremzin. 1986. Growth and development
of rice seedlings in soil salinity.Int. Rice Res. Newsl. 13(3): 42-44.
Sangakkara, U. R., U. A. Hartwig and J. Nosbeger. 1996. Response of root branching and shoot
water potentials of French bean (Phaseolus vulgaris L.) of soil moisture and fertilizer
potassium. J. Agron. Crop Sci. 177: 165-173.
Sen, A. K. 2002: Salinity tolerance studies of some transplanted aman rice cultivars. M.S. Thesis,
Department of Crop Botany, Bangladesh Agricultural University, Mymensingh.

Serraj, R. and J. J. Drevon. 1988. Effect of salinity and nitrogen source on growth and nitrogen
fixation in alfalfa. J. Plant Nutr. 21: 1805-1818.
Sexcion, P. S. H., J. A. Egdane, A. M. Ismail and M. L. D. Sese. 2009. Morphophysiological
traits associated with tolerance of salinity during seedling stage in rice.
Shanker, A. K., M. Djanaguiraman, J. A. Sheeba, D. D. Devi and U. Bangrusamy. 2007. Rice can
acclimate to lethal level of salinity by pretreatment with sublethal level of salinity
through osmotic adjustment. 85 Plant Soil. 284(1/2): 363-373.
Shazia I, S. Q. Muzammil, Y. A. Muhammad, H. Mumtaz and H. N. Naima. 2004. Influence of
sulphate of potash (sop) and farmyard manure (fym) on sugarcane (saccharum
officinarum l.) Grown under salt stress.
Singh, B. and K. Usha. 2003. Salicylic acid induced physiological and biochemical in wheat
seedling under water stress. Plant Grot. Regul. 39: 137-141.
Smith, D. C., V. Beharee and J. C. Hughes. 2001. The effects of composts produced by a simple
composting procedure on the yields of Swiss chard (Beta vulgaris L. var. °avescens) and
common bean (Phaseolus vulgaris L. var. nanus). Sci. Hortic. 91: 393-406.
Sohi, S. P. 2013. Pyrolysis bioenergy with biochar production—greater carbon abatement and
benefits to soil.Glob. Change Biol. Bioenergy 5: 1–3.
Soliman, M. S., H. G. Shalabiand W. F. Cambeil. 1994. Interaction of salinity, nitrogen and
phosphorus fertilization in wheat. J. Plant Nutri. 17: 1163-1173.
Soussi, M., A. Ocana and C. Lluch 1998. Effect of salt stress on growth, photosynthesis and
nitrogen fixation in chickpea (Cicer arietinum L.). J. Exp. Bot., 49: 1329-1337.

SRDI, 2010. Saline soils of Bangladesh. SRMAF Project, Ministry of Agriculture, Bangladesh.
1–60.
Stamatiadis, S., M. Werner and M. Buchanan. 1999. Field assessment of soil quality as affected
by compost and fertilizer application in a broccoli field (San Benito County, California).
Appl. Soil Ecol., 1: 217-225.
Steiner C, W. G. Teixeira, J. Lehmann, T. Nehls, J. L. V. de Macedo, W. E. H. Blum, W. Zech.
2007. Long term effects of manure, charcoal and mineral fertilization on crop production
and fertility on a highly weathered central Amazonian upland soil. Plant Soil. 291:275–
290.
Stoyanov, Z. Z. 2005. Effects of stress on leaf water relation of young bean plants. J. Cet. Eur.
Agric. 6(1): 5-14.
Sultana, N. T., R. Ikedaand and H. Itoh. 1999. Effect of salinity on yield attributes and yield in
rice genotypes. Env. Expt. Bot. 42: 211-220.
Tanji, K. K. 1990. Agricultural salinity assessment and management. ASCE manuals and reports
on engineering practice (USA).
Tejada, M., C. J. L. Garcia, Gonzalez and M. T. Hernandez. 2006. Use of organic amendment as
a strategy for saline soil remediation: Influence on the physical, chemical and biological
properties of soil. Soil Bid. Biochem. 38:1413-1421.
Thomas, S. C., S. Frye, N. Gale, M. Garmon, R. Launchbury, N. Machado, S. Melamed, J.
Murray, A. Petroff and C. Winsborough. 2013. Biochar mitigates negative effects of salt

additions on two herbaceous plant species. Journal of Environmental Management 129:
62–68.
Tryon, E. H. 1948. Effect of charcoal on certain physical, chemical and biological properties of
forest soils, Ecol. Soc. Am. 18: 81–115.
Van Zwieten, L., S. Kimber, S. Morris, K. Y. Chan, A. Downie, J. Rust, S. Joseph and A. Cowie.
2010. Effects of biochar from slow pyrolysis of papermill waste on agronomic
performance and soil fertility. Plant Soil. 327: 235–246.
Verheijen, F.G.A.; S. Jeffery, A. C. Bastos, van der Velde and M. I. Diafas. 2009. Biochar
Application to Soils—A Critical Scientific Review of Effects on Soil Properties,
Processes and Functions; Office for the Official Publications of the European
Communities: Luxembourg. EUR 24099 EN. 61.
Walker, D. J. and M. P. Bernal. 2004. Plant mineral nutrition and growth in a saline
Mediterranean soil amended with organic wastes. Commun. Soil Sci. Plant Anal. 35:
2495-2514.
Wanas, S. A. and W. M. Omran. 2006. Advantages of Applying Various Compost Types to
Different Layers of Sandy Soil: 1-Hydro-physical Properties. Appl. Sei. Res., 2: 1298-
1303.
Wardle, D. A., O. Zackrisson and M. C. Nilsson. 1998. The charcoal effect in Boreal forests:
mechanisms and ecological consequences. Oecologia. 115:419–426.
Yamato, M, Y. Okimori, I. F. Wibowo, S. Anshori and M. Ogawa. 2006. Effects of the
application of charred bark of Acacia mangium on the yield of maize, cowpea and peanut,

and soil chemical properties in South Sumatra, Indonesia. Soil Sci Plant Nutr. 52:489–
495.
Yeboah E, P. Ofori, G. W. Quansah, E. Dugan and S. P. Sohi. 2009. Improving soil productivity
through biochar amendments to soils. Afr J Env Sci Technol 3:34–4152:489–495.
Zeng, L. H., S. M. Lesch and C. M. Grieve. 2003. Rice growth and yield respond to changes in
water depth and salinity stress. Agric. Water Management. Elsevier Sci. B.V.,
Amsterdam, Netherlands. 59(l): 67-75.
Zhang A., R. Bian, G. Pan, L. Cui, Q.Hussain, L. Li, J. Zheng, J. Zheng and X. Zhang. 2012.
Effects of biochar amendment on soil quality, crop yield and greenhouse gas emission in
a Chinese rice paddy: A field study of 2 consecutive rice growing cycles. Field Crops
Resh. 127: 153–160.

APPENDICES
Appendix I. Rice husk biochar analysis (Chemical analysis)
pH N (%) P (%) K (%) Ca (%) Mg (%) S (%) EC ms/cm
Biochar 7.15 2.57 0.21 0.231 1.024 0.458 0.339 1.325
Appendix II. Rice husk biochar analysis (TGI, ash, volatile content analysis)
Thermo Gravimetric Index
(TGI)
Volatile content Ash content
at 1050C at 3500C at 6500C at 1000C at 9000C at 1000C at7500C
Biochar 1.89g 1.53g 0.99g 1.92g 1.82g 1.90g 0.90g