by bidyashree tripathy
TRANSCRIPT
SOIL ATTRIBUTES AS INFLUENCED BY MAIZE BASED CONSERVATION AGRICULTURE PRODUCTION SYSTEM
(CAPS) IN A Fluventic Haplustepts UNDER NORTH CENTRAL PLATEAU ZONE OF ODISHA
A
THESIS SUBMITTED TO THE ORISSA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
BHUBANESWAR
IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE IN AGRICULTURE (SOIL SCIENCE AND AGRICULTURAL CHEMISTRY)
By
Bidyashree Tripathy
DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY COLLEGE OF AGRICULTURE
ORISSA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY BHUBANESWAR-751003
2014
THESIS ADVISOR: DR. K. N. MISHRA
ORISSA UNIVERSITY OF AGRICULTURE AND TECHNOLOGY
DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL CHEMISTRY
COLLEGE OF AGRICULTURE, BHUBANESWAR
Dr. K. N. Mishra Associate Professor, Soil Science Bhubaneswar AICRP on IFS & Co-PI SMARTS Date: 31.07.14 Directorate of Research Bhubaneswar, Odisha
CERTIFICATE-I
This is to certify that the thesis entitled “Soil attributes as
influenced by Maize based Conservation Agriculture Production
System (CAPS) in a Fluventic Haplustepts under North Central
Plateau zone of Odisha” submitted in partial fulfilment of the
requirements for the award of the degree of Master of Sciences in
Agriculture (Soil Science and Agricultural Chemistry) to the
Orissa University of Agriculture and Technology is an authentic
record of bona fide research work carried out by Bidyashree
Tripathy under my guidance and supervision. No part of this thesis
has been submitted for any other degree or diploma.
It is further certified that the evidence and help obtained
by him from various sources during the course of investigation has
been duly acknowledged.
(K. N. Mishra) CHAIRMAN
ADVISORY COMMITTEE
CERTIFICATE CERTIFICATE CERTIFICATE CERTIFICATE –––– IIIIIIII
This is to certify that the thesis entitled “Soil attributes as
influenced by Maize based Conservation Agriculture Production
System (CAPS) in a Fluventic Haplustepts under North Central
Plateau zone of Odisha” Submitted by Bidyashree Tripathy to
Orissa University of Agriculture and Technology, Bhubaneswar in
partial fulfilment of the requirements for the degree of Master of
Science in Agriculture (Soil Science and Agricultural Chemistry)
has been approved/disapproved by the students’ Advisory Committee
and the external examiner.
Advisory Committee
CHAIRMAN: Dr. K. N. Mishra Associate Professor Soil Science
AICRP on IFS & Co-PI SMARTS
Directorate of Research MEMBERS: Dr. A. K. Pal
Professor and Head Dept. of Soil Science and Agricultural Chemistry
Dr. L. M. Garnayak Chief Agronomist AICRP on IFS OUAT, Bhubaneswar
EXTERNAL EXAMINER:
ACKNOWLEDGEMENT
One of the joys of completion is to look over the journey and remember all the persons
who have helped and supported along the ebbs and tides of this long but fulfilling road. It is my
pleasure and privilege to appreciate the persons whose constant efforts, motivation and well
wishes paved a path for me to write this column. In this moment, I am short of words to express
my feelings of gratitude and reverence and am just pouring a drop from the ocean of
indebtedness in form of words.
I ascribe all glory to the gracious, omnipotent and omnipresent Almighty, for his silent
blessing and kindness which acted as a savoir in the time of disasters and guarded me all along.
I am extremely delighted and feel blessed to have worked under the guidance of
excellent pursuing and ever helpful personality, Honourable chairman of my Advisory
committee, Dr. K. N. Mishra, Associate Professor, Soil Science and Agricultural Chemistry,
AICRP on IFS and CO-PI SMARTS, OUAT, Bhubaneswar. His invaluable and timeless
suggestion, constant inspiration, affectionate dealings, constructive criticism and advice helped
me at every stage. His innovative ideas, meticulous nature and close monitoring of the research
work molded the manuscript with perfection. My sense of obligation is negligible and
unquantifiable in respect of his energy and time spent on this endeavor. His benevolent
personality made a great impression on me and I wish to inculcate his positive energy.
I take privilege of expressing gratitude and gratefulness to Dr. L. M. Garnayak, Chief
Agronomist, AICRP on IFS for his concern and magnanimity in providing the research
laboratory and timely co-operation in all my statistical formalities. His help and advice is
always invaluable and it is my golden opportunity to have him as the member of my Advisory
committee.
It is my pleasure to express my deepest sense of regards to Dr. A. K. Pal, Professor and
Head, Department of Soil Science and Agricultural Chemistry, OUAT for his kind words,
immense patronage and encouragement in the study period.
I acknowledge with sincerity the fellowship awarded to me by the OUAT-University of
Hawaii collaborative research project “Sustainable Management of Agro-ecological Resources
for Tribal Societies (SMARTS)” for my research and study. In this context, I fell elated to
express my deepest sense of regards and infinitum gratitude to the members of SMARTS
Project Scientific team comprising of Dr. P.K. Roul, Associate Director of Research; Dr. K.N.
Mishra, Sr. Scientist (Soil Science); Dr. S.N. Dash, Associate Professor (Fruit Science) from
OUAT and Dr. C. Chan Halbrendt, Professor (NREM); Dr. T.W. Idol, Associate Professor
(NREM); Dr. C. Ray, formerly Interim Director, Water Resource Research Centre, from
University of Hawaii, USA for their immense patronage and valuable suggestions during the
course of my investigation.
I owe my heartiest gratefulness to the esteemed teachers of Department of Soil
Science And Agricultural Chemistry, Dr.S.Nanda, Dr.K.C.Pradhan, Dr.B.Dash,
Dr.S.K.Pattnayak, Dr.G.H.Santra, Dr.P.K.Das,Dr.A.Mishra, Dr.K.K.Rout, Dr.S. Mohanty,
Dr.A. K. Das, Dr.R.K.Nayak, Miss B.Jena, Dr.M.Mandal, Mr.S.Soren,Mr.M.Behera for
their timely suggestion and guidance throughout my post-graduate studies.
I am profoundly indebted to Dr. D. Jena, (former HOD of Soil Science) for his
encouragement, support and discussion during the course of formulation of the research topic.
My heartiest and sincere reverence to Dr. B. Hota (former Assoc. Professor, Dept. of Plant
Physiology) for being the anchor and guide since I stepped into this institution.
I am very much thankful to the help and cooperation of non-teaching staffs of the
department Bun bhai, Bulubhai, Anil bhai who acted as Lilliputians in handling the huge
research work. Thank you Dilip Sir, Sameer Sir, Majhi Sir, Mohanty Sir, Madhu didi,
SMARTS PC Shivashis bhai for their words of care and concern.
I express my deep love to my lovely friends Nita, Hyn, Prativa, Jessy Dee, Sipra,
Sushree, Gayatri who soothed and comforted me in my frustrations and despair. I thank all my
friends, sincere juniors and batchmates Meera, Trupti, Rahul, Shiva, Shyam bhai, Snehasish for
their kind cooperation. My heartiest gratitude is to my senior Ayesha Dee for her facile
suggestion and motivation.
I solicit the benediction of my parents, Nana and Bou for my progress and prosperity.
My Bou’s constant prayers and pious advices kept all negativity and failures in bay. I respect
the abundant love and shower of blessings of all my family members. I thank my beloved
brother, Milu for his unfathomable love and impulsiveness.
Any omission in acknowledgement does not mean lack of gratitude. Lastly, to all of
you, Thank You..!
Bhubaneswar
Dated (Bidyashree Tripathy)
ABSTRACT
Soil degradation due to loss of forest cover, water erosion and shifting cultivation
coupled with continuous monocropping of maize in intense tillage have led to a quest for
sustainable production practices with greater resource use efficiency in the rain-fed agro
ecosystem under North Central Plateau zone of Odisha. In order to reverse this harmful trend,
conservation agriculture production system (CAPS) with the components of minimum tillage,
legume based intercrops and follow up cover crop has been established in a Fluventic
Haplustepts at Regional Research and Technology Transfer Station, OUAT at Kendujhar
district of Odisha during 2011 in split plot design and the impact of CAPS on BD, WSA, SOC,
soil moisture and microbial attributes across the profile (0-5, 5-10 and 10-20 cm) was assessed
at the end of the 3rd cropping cycle. The treatment combinations are Conventional tillage (CT)
and Minimum tillage (MT) with sole Maize (M) and inter crop Maize + Cowpea (M+C) in
main-plots during wet season and Horsegram (H), Toria (T) and no cover crop (NCC) in sub-
plots during dry season. Surface accumulation and retention of SOM under MT decreased the
BD (-3.4%, -2.6%), increased the dry season moisture contents and SOC (+27.9%, +15.2%) in
the top two layers. Higher SOC in MT increase the water stable micro-aggregates (+14.9%,
+11.9%) with concomitant decrease in micro-aggregates(-14.8%, -14.5%) in 0-5 and 5-10 in
layers, indicating the low turn-over of macro-aggregates. Depletion of SOM induced by soil
conversion under CT systems increased the BD (+1.5%, +2.2%), decreased the SOC (9.8%, -
15.7%), macro-aggregates (-5.3%, -5.7%). The higher population of bacteria (+31.0%, +
25.5%), fungi (+22.0%, +18.6%) and actinomycetes (+ 19.9%, + 14.8%) and MBC (+88.1%,
+49.9%) in the top layers in MT over CT is due to higher build up and protection of SOM. The
pronounced effect of cover crops due to litter inputs was reflected on SOC (+13.0%), Macro-
aggregates (+7.2%), population of bacteria (+21.8%), fungi (+15.1%), actinomycetes (+12.2%)
and MBC (+21.5%) in the surface layer of 0-5 cm. The attributes in the bottom layers (10-20
cm) remain unaffected by tillage practices because of low and lack of variation in SOC
contents. The study singles out SOC as the most dominant soil parameter affecting soil BD (r =
- 0.85** , r = -0.89** ), water stable macro-aggregates (r = 0.90** , r = 0.76** ), soil moisture ( r =
0.82** , r = 0.82** ), MBC ( r = 0.98** , r = 0.99** ), population of bacteria ( r = 0.91** , r = 0.77** ),
fungi ( r = 0.86** , r = 0.88** ) and actinomycetes ( r = 0.87** , r = 0.86** ) in the surface (0-5 cm)
and sub surface (5-10 cm) layers. Though the MEY of MT and CT systems are at par, the
established positive trend in restoration and enrichment of soil attributes at the end of the 3rd
year will enhance the productivity of soil on long term basis.
CONTENTS
CHAPTER PARTICULARS PAGE
I INTRODUCTION 1
II REVIEW OF LITERATURE 4
III MATERIALS AND METHODS 25
IV RESULTS 39
V DISCUSSION 69
VI SUMMARY AND CONCLUSION 80
BIBLIOGRAPHY i-xiv
LIST OF TABLES
3.1 Mean Monthly meteorological data during the cropping season 28
(2013 - 2014)
3.2 Treatment details 31
3.3 Crop varieties and their duration 33
3.4 Fertiliser dose for different experimental crops grown 33
4.1 Soil BD (Mg m-3) as influeneced by different CAPS 40
4.2a Effect of CAPS on water stable macro-aggregates (>0.25mm) 43
4.2b Effect of CAPS on water stable micro-aggregates (0.053-0.25mm) 45
4.3a Effect of CAPS on soil moisture content (%) at 0-5cm depth 47
4.3b Effect of CAPS on soil moisture content (%) at 5-10cm depth 48
4.3c Effect of CAPS on soil moisture content (%) at 10-20cm depth 49
4.4 Effect of CAPS on soil pH (1:2.5) 51
4.5 Soil Organic Carbon (g kg-1) as influenced by CAPS 53
4.6 Bacterial population (×106 cfu g-1) as influenced by CAPS 56
4.7 Population of fungi (×104 cfu g-1) as influenced by CAPS 58
4.8 Population of actinomycetes (×106 cfu g-1) as influenced by CAPS 60
4.9 Impact of CAPS on soil MBC (µg C g-1) 62
4.10 Microbial quotient (MBC/ SOC) [%] as influenced by CAPS 65
4.11 Effect of CAPS on Maize Equivalent Yield (q ha-1) 66
TABLE PARTICULARS PAGE
LIST OF FIGURES Figure Particulars Page
3.1 Agroclimatic zones of Odisha 26
3.2 Study area with profile site and external land features 27
3.3 Mean monthly rainfall and rainy days during the cropping 29 season (April 2013-March 2014)
3.4 Mean monthly temperature and relative humidity data during 29 the cropping season (April 2013-March 2014)
3.5 Layout plan of the experiment plot 30
3.6 Representative pedon of the experimental site 32
3.7 Many coarse and medium lime nodules and carbonate coats 32 in ‘B’ horizon
3.8 Site features around the pedon site 32
3.9 Wet-sieving of Water stable aggregates 35
3.10 Chloroform (CH3Cl) fumigation for MBC 35
3.11 Actinomycetes population in both CT and MT type of 35 cropping systems
3.12 Maize stalk and residue incorporation in MT system 35
4.1 Soil BD (Mg m-3) as influenced by CAPS. Treatmnets with 41 same lower case letter within main plots or sub-plots were not significant at P = 0.5
4.2a Effect of CAPS on water stable macro-aggregates (>0.25mm) 44 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.2b Effect of CAPS on water stable micro-aggregates (0.053-0.25mm) 46 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.3 Periodical soil moisture content across the profile 50
4.4 pH of soils of 0-5cm depth as influenced by CAPS. Treatments 52 with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.5 Soil Organic Carbon (g kg-1) as influenced by CAPS. Treatments 54 with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.6 Bacterial population (×106cfu g-1) as influenced by different CAPS. 57 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.7 Fungal population (×104cfu g-1) as influenced by different 59 CAPS. Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.8 Population of actionomycetes (×106cfu g-1) as influenced 61 by different CAPS
4.9 Microbial Biomass Carbon (µg of C g-1) as affected by CAPS. 64 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.10 Microbial quotient across the profile as influenced by CAPS. 65 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.11 Effect of different CAPS on Maize Equivalent Yield (q ha-1) 66 Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
4.12a Depth wise graph showing distribution of SOC, WSA 67 under different tillage systems
4.12b Depth wise graph showing distribution of MBC and Microbial 68 quotient under different tillage systems
5.1 Correlation of SOC with BD 70
5.2 Correlation of SOC with water stable macro-aggregates 71
5.3 Correlation of SOC with water stable micro-aggregates 72
5.4 Correlation of SOC with soil moisture content at sowing and 73 flowering at 0-5cm soil depth
5.5 Correlation of SOC with pH in 0-5cm soil layer 74
5.6 Correlation of SOC with MBC of the soils 76
5.7 Correlation of SOC with bacterial population of the soils 77
5.8 Correlation of SOC with fungal population of the soils 78
5.9 Correlation of SOC with actinomycetes population of soils 78
ABBREVIATION
FAO : Food and Agriculture Organisation CAPS : Conservation Agriculture Production System CA : Conservation Agriculture CT : Conventional Tillage MT : Minimum Tillage SOC : Soil Organic Carbon HG : Horsegram NCC : No Cover Crop BD : Bulk Density NT : No Tillage WSA : Water Stable Aggregate MBC : Microbial Biomass Carbon Mg : Megagram µg : microgram ha : Hectare CD : Critical Difference SE(m) : Standard Error mean SMC : Soil Moisture Content NS : Non-significant
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INTRODUCTION
Food security for our country’s burgeoning population is becoming
increasingly difficult and this challenge needs to be met in the face of the changing
consumption patterns, impacts of the climate change and degradation of the finite land
and water resources. Management of land resources, in general, encompass, crop
production methods that will keep pace with country’s food needs, sustaining
environment, blunting impacts of climate change, preserving and enhancing natural
resources, and supporting livelihood of farmers and rural population of the country.
Sustainable crop production without any degradation of natural resources can be
achieved through a set of crop-nutrient-water-landscape system management practice
popularly known as conservation agriculture production system.
Conservation agriculture (CA) involves minimal soil disturbance, continuous
retention of residues on the soil surface and a diverse and rational use of crop
rotations (Erenstein et al., 2008). Conservation agriculture production systems
(CAPS) are tailor-fit system approaches for successful adoption and implementation
of CA to specific locations (Agustin et al., 2012).
Soil organic matter (SOM) is an important determinant of soil fertility,
productivity and sustainability and is a useful indicator of soil quality in tropical
agricultural systems where nutrient pool and highly weathered soils are managed with
little external input (Lal, 1997). In the humid and sub-humid tropics, climate is
especially aggressive and soils are frequently deficient in nutrients and prone to
erosion, while the rate of SOM decomposition is usually high. The role of SOM in
moderating the major soil quality indicators like SOC, BD, aggregation, moisture, and
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microbial biomass carbon is well documented. The dynamics of SOM are influenced by
agricultural management practices such as tillage, crop residues and cropping systems as
the basic components of CAPS. Conventional tillage practices and removal of crop residues
can lead to a reduction of SOM due to accelerated decomposition and loss of organic matter
in rich top soils (Arshad et al., 1990), thereby adversely affecting soil properties.
In response to above challenges, scientists have focused on developing alternative
cropping system over the past few decades and conservation agriculture production
systems are among those that have been the most extensively tackled. They rely on
three principles:
i. A significant reduction in soil tillage
ii. A permanent soil protection through cover crops
iii. Increased bio-diversity through diversification of crop rotation and/or
intercropping
Minimum tillage are those systems which are ploughless but do not
completely abandon tillage and such reduced tillage systems vary largely in terms of
machinery used and of tillage depth. The tillage systems reaching a maximum depth
of 10 cm are defined as minimum tillage (MT). Several studies world over indicate
that MT soils increases SOM, MBC, aggregation and microbial densities. Crop
rotation can affect SOM because the SOM content depends on the type of crop
rotation, the quality and quantity of crop residues and since crop residues are
precursors of the SOM pool, returning more crop residues to the soil is associated
with an increase in SOC concentration (Fuentes et al., 2012). Cover crops or crop
residues should be maintained on the soil surface as dead or live mulch and the
objective is to protect the soil against weather aggressions and water erosion, to
maintain soil moisture, to suppress weed growth and to provide shelter and food for
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the soil biota. Therefore, conservation agriculture production systems (CAPS) appear
to be interesting options to achieve sustainable and intensive crop production under
different agro-ecological environments because they use available resources
efficiently and maintain soil fertility.
Despite the considerable research done world over, which show the benefits of
CAPS on SOC, very little effort has been done in the rainfed agro-ecosystem under
North Central Plateau zone of Odisha to investigate the influence of CAPS on soil
attributes. Keeping these facts in view, a field experiment with maize based CAPS has
been established at Regional Research and Technology Transfer Station, Kendujhar
during 2011 and objectives of the present study are described below.
Objectives
The objective of the study is to assess the influence of maize based CAPS
involving tillage practices (minimum tillage and conventional tillage), cropping
systems (maize sole and maize+cowpea intercrop) and both with and without cover
crops (horsegram and toria) on soil attributes across the profile at the end of 3rd
cropping cycle (2013-14). The studies are:
1. Determination of soil BD and water stable macro and micro
aggregates
2. Determination of gravimetric moisture content (during rabi season
cover crops)
3. Monitoring the pH, and organic carbon status of the soils
4. Monitoring the microbial attributes viz. population of bacteria, fungi,
actinomycetes and microbial biomass carbon (MBC) of the soils
5. Assessing the impact on Maize Equivalent Yield (MEY)
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REVIEW OF LITERATURE
Conservation agriculture production system (CAPS) is a tool box of practices
for successful adoption and implementation of conservation agriculture (CA) to
specific locations. Some of the significant research findings on CA, relevant to the
present study “ Soil attributes as influenced by maize based conservation
agriculture production system (CAPS) in a Fluventic Haplustepts under North
Central Plateau Zone of Odisha” have been thoroughly reviewed and presented in
this chapter under the following heads.
2.1 Conservation Agriculture Production System (CAPS),
Definition, Principles and Importance.
2.2 Impacts of Conservation Agriculture Production System
(CAPS) on soil health
2.2.1 Soil physical properties
2.2.1.1 Bulk density
2.2.1.2 Water stable aggregates
2.2.1.3 Soil Moisture Content
2.2.2 Soil chemical properties
2.2.2.1 Soil reaction (pH)
2.2.2.2 Organic carbon
2.2.3 Soil microbial properties (population of bacteria, fungi
actinomycetes and microbial biomass carbon)
2.3 Conservation Agriculture Production System (CAPS ) -Yield
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2.1 Conservation Agriculture Production System (CAPS), Definition, Principles and Importance.
2.1.1 Definition of conservation agriculture
Conservation agriculture (CA) can be defined as “ a concept for
resource-saving agricultural crop production that strives to achieve acceptable
profits together with high and sustained production levels while concurrently
conserving the environment” (FAO,2007).
‘ Conservation Agriculture’ refers to a general set of practices that are focused on
three main concepts - minimum tillage to reduce soil disturbance; continuous soil
cover to reduce rainfall impact, suppress weeds and conserve organic matters and
optimal crop rotation to maintain soil fertility and provide nutritional self-efficiency
(FAO, 2010).
Conservation tillage is a widely-used terminology to denote soil
management systems that result in at least 30% of the soil surface being
covered with crop residues after seeding of the subsequent crop to reduce soil
erosion. (Jarecki and Lal, 2003; Uri, 1999).
Conservation agriculture (CA) can be defined as “ a concept for resource-saving
agricultural crop production that strives to achieve acceptable profits together with
high and sustained production levels while concurrently conserving the environment”
(FAO,2007).
‘Conservation Agriculture’ refers to a general set of practices that are focused on
three main concepts - minimum tillage to reduce soil disturbance; continuous soil cover
to reduce rain fall impact, suppress weeds and conserve organic matters and optimal crop
rotation to maintain soil fertility and provide nutritional self-efficiency (FAO,2010).
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2.1.2 Principles of conservation agriculture
Conservation agriculture makes use of soil biological activity and cropping
systems to reduce the excessive disturbance of the soil and to maintain the
crop residues on the soil surface in order to minimize damage to the environment
and provide organic matter and nutrient.
Conservation agriculture production system is characterized by three
principles which are linked to each other (FAO, 2010), namely:
1. Continuous minimum mechanical soil disturbance, mainly through
direct seeding = No-tillage
2. Permanent organic soil cover, organic matter supply through the
preservation of crop residues and cover crops = Mulching and
Cover cropping
3. Diversification of crop species grown in sequence or associations
for biocontrol and efficient use of the soil = Rotation
Reduced tillage or no-tillage is also a principal component of CA as it is
designed to improve soil quality. This differs from conventional tillage by
advocating minimum soil disturbance and promoting direct seeding which involves
growing crops without mechanical seedbed preparations after harvesting the
previous crop (Calegari, 2008).
Cover crops are grown to provide soil cover and are killed before seeding. They
have been used to augment biomass of crop residues, protect soils against erosion and
promote build up of soil organic matter (Muza et al., 2007). They are an integral
component of CA and the main focus of this study.
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Generally planned rotations involving cereals and legumes are
necessary to promote nutrient recycling because of distinct rooting depths in cereal-
legume systems (Tsubo et al., 2003).
2.1.3 Importance of conservation agriculture
Conservation agriculture advocates the combined social and
economic benefits gained from combining production and protecting the
environment, hence it becomes in integration of ecology management with
modern scientific agricultural production. This is compounded by the fact that
yield improvement under farming takes a few years to be manifested
(Hubbs et al., 2007).
Conservation agriculture production system are recommended as a general
solution to the problems of rural communities facing poor agricultural
productivity and declining natural resource quality (Derpsch, 2003; Hubbs,
2007; Hubbs et al., 2008).
Compared to conventional tillage there are several benefits from conservation
tillage such as economic benefits by labour, cost and time saved, erosion
protection, soil water conservation and increases of soil organic matter (Uri et
al.1998; Wang and Gao, 2000)
2.2 Impacts of Conservation Agriculture Production System (CAPS) on soil health
Doran and Parkin (1994), Doran and Safley (1997) initially
distinguished between “ soil quality” and “ soil health” before inclusively using
the term “ soil health” and defining it as “ the continued capacity of soil to
function as a vital living system, within ecosystem and land-use boundaries, to
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sustain biological productivity, promote the quality of air and water environments,
and maintain plant, animal and human health”.
However, the general perception of a healthy or high-quality soil is one that
adequately performs functions, which are important to humans, such as providing a
medium for plant growth and biological activity, regulating and partitioning
water flow and storage in the environment and serving as an environmental buffer in
the formation and destruction of environmentally hazardous compounds.
Reeves (1997) noted that “ SOC is the most often reported attribute from long-
term agricultural studies and is chosen as the most important indicator of soil
quality and agronomic sustainability because of its impact on other physical,
chemical and biological indicators of soil quality” .
For example, the humic fraction is considered the principal pool in contributing
to the soilís CEC, whereas soil structure is provided and maintained by both the
humic and particulate organic carbon (POC) fractions. Here, the POC fraction plays a
greater role in sandy soils as a means of physically binding particles together. In
turn, this means that with an increase in SOC content, there is increased aggregation
and decreased Db, which tend to increase the total pore space as well as the number
of small pore sizes (Haynes and Naidu,1998).
Over a long period, improved organic matter under the practice of
Conservation Agriculture promoted good soil structure and macro-porosity. Water
infiltrates easily, similar to forest soils (Machado, 1976).
Tillage and residue management increased soil profile water content.
(Nicou and Chopart, 1979, Unger, 1991 and Bruce et al., 1995) reported that
soil nutrients become stratified when no-till management is employed.
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Cover crop residues remaining on the surface can reduce evaporation, thus
conserve soil moisture, lower soil surface temperatures, provide a certain degree of
weed control, and minimize erosion (Liebl et al., 1992).
Reducing tillage affects several aspects of the soil. With time, conservation
tillage improves soil quality indices (Dick, 1983; Lal et al., 1998), including
soil organic C storage (Dick, 1983; Lamb et al., 1985; Unger, 1991; Bruce et
al.,1995; Potter et al., 1998).
Conservation tillage is an effective practice to control soil degradation on
intensively farmed cropland (Larney and Kladivko, 1989; Grant and Lafond,1993)
and to increase soil water storage (Dao, 1993).
The advantages of conservation tillage practices over crop residues to act as
an insulator and reducing soil temperature fluctuation; (N. D. Uri,1999) building up
soil organic matter; conserving soil moisture (Schwab and Reeves, 2002; West and
Post, 2002).
No-tillage is a sustainable cropping management system that protects soil,
water, air, and biodiversity (Hubbs et al., 2007; Campbell et al., 2006;
Calegari et al., 2008).
Soils managed using reduced tillage generally have more surface plant
residues, higher moisture content, and better structure and aggregation
compared to soils managed under Conventional tillage. (Reeves 1997)
Crop residues left on the soil surface lead to improved soil aggregation and
porosity, and an increase in the number of macro-pores, and thus to greater
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infiltration rates. On bare soil, runoff and thus soil erosion is greater than when the
soil is protected with residue cover (Ruedell, 1994).
No tillage retained the highest moisture followed by minimum tillage, raised bed and
conventional tillage in inceptisols under semi- arid regions of India (Sharma et al., 2011).
Karlen et al. (1994) showed that normal rates of residue combined with
zero-tillage resulted in better soil surface aggregation, and that this could be
increased by adding more residues.
Surface (0-30 cm) soil in a no-till system was shown to contain more moisture
and to be cooler than a comparable plough tillage soil (Doran et al.,1998).
Residue retention and direct seeding have a major influence on improving
water infiltration, organic matter content and fertility of a soil (Wall,1999).
No-tillage practices featuring residue cover and less soil disturbance have
been shown to reduce runoff by 52.5% and reduce erosion by 80.2% compared
to traditional tillage (Wang, 2000). Landers (2001) concluded an improvement of
the infiltration capacity under NT farming.
Trials conducted in the higher potential areas of Zimbabwe between 1988
and 1995 indicated that mulching significantly reduced surface runoff and hence
soil loss (Erenstein, 2002).
Luo et al. (2005) reported that conservation tillage can improve soil physical
properties and soil fertility in northern China and Bescanca et al. (2006) reported
that Conservation tillage leads to positive changes in the physical, chemical
properties of a soil. Conservation agriculture improves soil quality such as improved
exä|xã Éy _|àxÜtàâÜx
11
sequestration of organic carbon and improved soil fertility reported by (Hobbs and
Gupta, 2004).
Bolliger (2006) observed that positive changes on soil physical and chemical
properties occur only after several years of practicing conservation agriculture. NT
has positive effects on soil properties, yields and prevents erosion (Derpsch, 2006).
2.2.1 Soil physical properties
2.2.1.1 Bulk density
Bulk density is related to natural soil characteristics such as texture,
organic matter, soil structure (Chen et al., 1998).
A study on long term impact of no-till on soil properties and crop productivity
on Canadian prairies by Lafond et al. (2011) revealed that the lower soil BDs for the
native soil is likely due to more aggregation and higher litter content at the soil
surface. The higher soil BD on the convex areas of LTNT and STNT would have
also been strongly influenced by a combination of tillage and water erosion moving
soil into the concave areas, thus explaining the lower soil BD for concave areas.
While reviewing some of the studies on the effect of no- tillage on soil BD,
Fengyun et al. (2011) observed that the lower soil bulk density when compared with the
traditional methods by the end of the growing season may be derived from the more
intense plant root operation, soil organism movement and the function of soil freeze and
melt, as well as the well known increased soil water content and increased crop residue
amounts, would also decrease bulk density in the 0 to 5 cm soil layer.
Experiments on different tillage practices in sloppy terrains of North- West
Tuinisia by Jemai et al. (2013) showed significant reduction of BD and enhancement
exä|xã Éy _|àxÜtàâÜx
12
of TP (Total Porosity) under NT 7, that may be attributed to the considerable
improvement in SOM and biotic activity by residue incorporation.
The study on the effect of conservation tillage practices on soil water holding
capacity in the Loess plateau, China has indicated that conservation tillage practices
can increase the water and nutrient contents of the soil, reduce soil erosion, improve
soil structure and increase crop yields. NTS (NT with corn straw) treatments
decreased the soil bulk density and increased the soil porosity in 2008 and 2009
relative to the PT (Plough Tillage without corn straw) treatment (Liu et al., 2013)
The studies of Latif et al. (1992) revealed that legume intercrops in a
conservation agriculture system significantly decreased the soil bulk density and
penetration resistance.
Ekeberge and Riley (1997) found that bulk density was lower with minimum tillage
than with conventional tillage at a depth of 3-7cm in a loam soil in Southeast Norway.
Kay and Vanden Bygaart (2002) observed that bulk density was lower under
minimum tillage than mouldboard plough in the top 20cm of the soil profile
with the greatest difference at 5-10cm. This was probably due to organic matter
content at 0-5cm was greater under minimum tillage than mouldboard plough.
D’Haene et al. (2008) reported that bulk density was lower in 5-10cm soil
layer under minimum tillage than conventional tillage on silt loam soils with
crop rotations in Belgium.
Hernanz et al. (2002) found significantly lower bulk density under minimum
tillage than conventional tillage from 0-10cm with cereal mono-culture and
exä|xã Éy _|àxÜtàâÜx
13
from 0-15 cm in a wheat-vetch (Vicia sativa l.) rotation. But the more
compacted top soil with minimum tillage had no adverse effect on crop yield
with either rotation.
Blanco-Canqui et al. (2006) reported that maize residue retention at 5 and
10 Mg/ha for a period of one year reduced bulk density in 0-5cm layer from
1.42 Mg/m3 ( control) to 1.26 Mg/m3 and 1.22 Mg/m3 respectively in minimum
tillage system in a silt loam soil.
Thomas et al. (2007) reported that bulk density was lower with minimum
tillage than with conventional tillage in the top 10cm of a Luvisol in Southern
Queensland.
2.2.1.2 Water stable aggregate
Several researchers related increased macro-aggregate contents to
higher inputs of fresh organic material due to increased microbial activity and the
production of microbial and fungal derived binding agents (Mikha and
Rice, 2004).
This increase in the concentration of SOC is considered to be the result of
different interacting factors, such as less mixing and soil disturbance, increased residue
return, reduced surface soil temperature, higher moisture content and decreased
risk of erosion (Logan et al., 1991; Blevins and Frye, 1993).
Six et al. (2000b) and Jacobs et al. (2009) found for long-term agricultural
field experiments a decrease of macro-aggregate contents under CT in
comparison with no-tillage (NT) and reduced tillage (rotary harrow to 5-8 cm
depth), respectively.
exä|xã Éy _|àxÜtàâÜx
14
In contrast, conventional tillage (CT) disrupts macro-aggregates and formerly
incorporated Corg is exposed to microbial decomposition (Balesdent et al.,
2000; Six et al., 2000a; Tan et al., 2007; Zotarelli et al., 2007)
Greater aggregate stability was anticipated because the conservation
management practices were expected to increase the amount of labile C
available for use by microbial communities, which in turn, would produce more
organic binding agents and sticky fungal hyphae as a means to stabilize soil
Conceptual model of the ‘life cycle’ of a macro-aggregate (Six et al., 2000a)
Macro-aggregates (Roberson et al. 1991 ; Angers et al. 1992). Macro-
aggregation, in turn, may increase the proportion of labile organic C that is
physically protected from microbial decomposition (Boehm and Anderson 1997).
exä|xã Éy _|àxÜtàâÜx
15
The classical theory of aggregate formation and turnover has been postulated
by Six et al., 2000a. Following incorporation of fresh residues, soil micro-organisms
utilize the more easily available C and produce mucilages (solution gum) resulting
the formation of macro-aggregates around coarse (>250 µm) Intra-aggregate
Particulate Organic Matter (coarse iPOM). Coarse iPOM is further decomposed and
fragmented into fine iPOM. The fine iPOM and associated mucilages bind the
minerals, form the organic core of a newly developed micro-aggregates within
macro-aggregate. The latter process is cut short if the macro-aggregate turnover is
increased by disturbance resulting in a reduced sequestration of C.
It has been established that the inclusion of organic materials within soil
aggregates reduces their decomposition rate. Increases in aggregation concomitant
with increases in organic C have been observed in NT systems. Tillage has been
found to induce a loss of C-rich macro-aggregates and a gain of C-depleted micro-
aggregates However, this decrease in macro-aggregates cannot explain the total C
loss associated with tillage. The increased macro-aggregate turnover under CT is a
primary mechanism causing decreases of soil C. Macro-aggregate formation and
degradation (i.e. aggregate turnover) is reduced under NT compared to CT and leads
to a formation of stable micro-aggregates in which carbon is stabilized and
sequestered in the long term( Six et al., 2000).
The fractionation of water-stable aggregates and density fractionation may
thus be helpful for an improved understanding of C dynamics affected by soil
management, since aggregate and density fractions are more sensitive to changes
in soil management than total Corg Water-stable macro-aggregates were enriched
in younger organic material and have faster turnover times than micro-aggregates
(Andruschkewitsch et al., 2013).
exä|xã Éy _|àxÜtàâÜx
16
Aggregate stability in the surface soil of a sloping land is an important
predictor of run-off, sediment and carbon loss through water erosion. It mainly
depends on SOC which is influenced by land use practices. The contribution of
coarse soil aggregate (>0.05 mm) in adsorption of SOC is more than micro
aggregates (<0.05 mm), while it is damaged by improper agriculture activities
(such as heavy tillage practices, burning of crop residue), grazing and forest
clearance. Furthermore, the coarse soil aggregate is reduced mainly by long- term
conventional tillage practices (Heshmati et al., 2011).
The study of Li and Pang (2010) on a silty clay loam soil in China revealed that
long-term (33 years) practices of this tillage resulted in reduction of 22% in coarse
aggregates and increase of 34% in fine aggregates (Li, G.L. and X.M. Pang, 2010).
When no tillage was continuously practiced for 4 years, 11 years and 20 years
in Typic Xerofluvents of north east Spain, it was observed that small macro- aggregates
(0.250-2.0mm) & micro-aggregates(0.053-0.250mm) increased at a depth of 0-5cm
and 5-10cm. In contrast, small macro-aggregates and micro- aggregates reduced in
conventional tillage (D. Plaza Bonilla et al, 2013).
Conventional tillage (CT) disrupts macro-aggregates (Gale et al., 2000). Micro-
aggregates are more stable than macro-aggregates and tillage subsequently disrupts large
aggregates more than smaller aggregates (Cambardella and Elliot, 1993).
In red tropical latosols in Brazil, it was found that no-tillage system had the
best aggregation indices for the 0-20 cm layer due to the increase in the organic
carbon content. , Castro Filho et al. (2002).
exä|xã Éy _|àxÜtàâÜx
17
In Florida, a no tillage chronosequence study of 0, 6, 10 and 15 years in
commercial plots revealed that there exist a relationship between the increase
in the surface soil water stable macro aggregate and the hydrolysable organic carbon
with longer years under no tillage (Ochoa et al., 2009).
2.2.1.3 Soil moisture contents
In a seven-year study (Jones, 2000), it was found that zero tillage systems with
cereal residue retention could enhance the soil moisture status.
Minimum tillage treatments produced higher maize yields than conventional tillage
treatments and conserved more soil moisture in the soil. The results also indicated that
minimum tillage treatments had more compact and moister soil surface than conventional
tilled treatments. Overall increased crop yield under minimum tilled treatments was
associated with improved soil moisture conservation (Gicheru et al., 2005).
Minimum tillage with vegetative barriers not only reduced soil loss though erosion,
also conserved soil moisture in the dry season that was reflected in improved yield
(Guto et al., 2012).
Tillage reduction in association with residue retention significantly increased the
water holding capacity in the present study, mainly due to large increase in soil
organic C in residue retained treatments in dryland agro-ecosystem at BHU, Varnasi
(Kushwaha et al., 2001).
Daraghmeh et al., 2009 observed that tillage reduction in association with residue
retention significantly increased the moisture contents in the surface layers mainly due to
large increase in SOC in a typical Danish morainic sandy loam Agrudalfs.
exä|xã Éy _|àxÜtàâÜx
18
2.2.2 Soil chemical properties
2.2.2.1 Soil reaction (pH)
Soils under NT practice are frequently more acidic in the surface layers but less acidic
in deeper layers than under CT practice as a result of an increase in organic matter and
associated organic acids and changes in the proportions of cations and anions in soil under
NT practice (Logan et al., 1991; Prasad and Power, 1991; Kern and Johnson, 1993).
Increase in soil organic C and N and a slight pH decline in the seed zone
under conservation agriculture practices improves the soil quality (Bessam
and Mrabet, 2003).
There was a significant negative correlation between pH and organic carbon
concentration ( r = -0.88, P ˂0.01), indicating that greater organic carbon under NT
may at least partially have had an acidifying effect. (Thomas et al., 2007 ).
2.2.2.2 Organic carbon and organic matter
On a Vertisols in southern Queensland, highest concentration of organic C in
the surface soil was found with a combination of NT, stubble retention and fertilizer
N (Dalal, 1989) or NT and stubble retention (Thompson, 1992).
Heenan et al. (1995) also found greater amount of organic C in 0ñ10 cm
depth under NT and stubble retained than under CT and stubble burned in a
coarse- textured red earth with 29% clay.
The studies of Six et al., (2000a) and Tan et al., (2007) revealed that the lower
physical impact of conservation tillage increases aggregate stability, leading to lower
aggregate turnover rates and therefore improved physical protection of Corg from
decomposition and thus higher Corg stocks in arable soils. In contrast, conventional
exä|xã Éy _|àxÜtàâÜx
19
tillage (CT) disrupts macro-aggregates and formerly incorporated Corg is exposed to
microbial decomposition
When no tillage was practiced for 7 years continuously in the sloppy
terrains of North-West Tuinisia, the soil organic matter was found to be more i.e.
31.0 g kg-1 & 24.1 g kg-1 at depths of 0-10 cm & 10-20 cm. But soil organic matter
was much lower i.e. 20.6 g kg-1 & 22.4 g kg-1 at depths of 0-10 cm and 10-20
cm respectively when conventional tillage was practiced (Jemai et al., 2013).
Long term studies on no tillage in a Typic Xerofluvents of North east Spain
indicated that the increase in the proportion of stable macro-aggregates and the
enrichment of C concentration of micro-aggregates are the main mechanisms of
SOC protection when NT is maintained over time (D. Plaza- Bonilla et al., 2013).
Studies conducted under a wide range of climatic conditions, soil types, and
crop rotation systems showed that soils under no-tillage and reduced tillage
have significantly higher soil organic matter contents compared with conventionally
tilled soils (R. Alvarez, 2005).
Havlin et al. (1990) determined that reducing tillage and maintaining surface
residues in a long-term study increased soil organic carbon content. He conducted an
experiment having three crop rotation-continuous soybean, continuous sorghum,
sorghum-soybean. These were managed for 12 years under conventional and no
tillage systems (0 and 100% surface residue cover respectively). Under no tillage soil
organic matter increased up to 45% as the level of residue increased from 1 to 3 t/ha/yr.
A study in eastern Paraguay about “changes in soil organic matter after
land use change” showed that no tillage practices had a significant higher
exä|xã Éy _|àxÜtàâÜx
20
organic matter content compared with conventional tillage practices (Riezebos
and Loerts, 1998).
In Texas, Zibilske et al. (2002) recorded that no tillage resulted in soil
organic matter increase up to 58% in the top 4cm of soil for no till treatment.
Six et al. (2002) concluded that there is an increase in soil organic matter
after doing a literature review about soil organic matter dynamics in tropical
and temperate countries under the NT system. He concluded that in the upper 40
cm the soil organic matter increases after 6-8 years.
Balota et al. (2004) showed that in Brazil in a 20-year experiment
residue retention and minimum tillage increased organic carbon by 45% at 0-
50cm depth compared with traditional tillage.
Madari et al. (2005) and Riley at al. (2005) showed that conservation tillage
with residue cover had higher total organic carbon in soil aggregates than
traditional tillage in Brazil. He reported that addition of crop residues in
combination with minimum tillage can yield attainable carbon
accumulation rates up to 0.36 Mg C ha-1 yr-1.
Li et al. (2006) conducted a 4 years no-tillage experiment and showed that
active C and total organic C down to 10 cm depth were up to 5% higher in no-
tillage than traditional tillage systems.
Liang et al. (2007) demonstrated that no tillage significantly increased the
concentration of soil organic C in 5-20 cm soil layer by 5.6-5.9% on the clay
loam soils after 3 years in the humid north eastern China.
exä|xã Éy _|àxÜtàâÜx
21
Field experiment conducted in Santo Antonio de Goias, Brazil by A.S.
Nascente et al. (2013) revealed that the use of cover crops such as millet and the no-
tillage system increased C and N concentrations in each of the light fractions of the SOM.
Although total SOM was little changed during the two years of this experiment, the
various C fractions were significantly affected by the tillage. They concluded that SOM
physical fractionation is good indicator to show significant differences caused by the soil
management in the organic matter dynamics in a short period of time.
2.2.3 Soil microbial properties (population of bacteria, actinomycetes and microbial biomass carbon)
Roldan et al. (2003) showed that after 5 years of NT maize in Mexico, soil
wet aggregate stability had increased over conventional tillage (TT) as had soil
enzymes, soil organic carbon (SOC) and microbial biomass (MB). They
conclude that NT is a sustainable technology.
CA results in more biotic diversity in the soil as a result of the mulch and
less disturbance. The surface mulch also helps moderate soil temperatures and
moisture, which is more favorable for microbial activity. MBC is 83% higher in
MT that CT (Balota et al., 2004).
Studies on Impact of tillage and residue incorporation on soil microbial
biomass C and N in dry land farm (Inceptisols) of BHU by Kushwaha et al.
(2001) indicated that when flushes of C are supplied to the soil in the form of
crop residues, the microbial biomass increases in size until the substrate is
depleted. In the present study, residue retention and tillage reduction both
increased the level of soil microbial biomass, the maximum effect on microbial
biomass being recorded in MTCR, either alone or in combination.
exä|xã Éy _|àxÜtàâÜx
22
It has been reported that use of minimum and zero tillage retained more crop
residue C as soil organic C and soil MBC compared to conventional tillage
(Salinas-Gracia et al., 1997). Singh and Singh (1993) stated that microbial
growth due to the application of organic matter such as straw is mainly
dependent on the availability of C in the soil; they reported 77% increases for
MBC and MBN under straw C fertilizer, and 51 and 84% increases under
straw treatment for MBC and MBN, respectively.
Soil organic matter (SOM) also plays a key role in soil quality The size of
the microbial community is directly proportional to SOM content and soil
microbes are the principal mediators of nutrient cycling (Hamel at al.,
2006). Although soil microbial biomass represents only a small proportion of
overall SOM, it is more dynamic than total SOM and a better indicator of how
tillage and cropping systems impact soil health and productive capacity (Lupwayi
et al., 1998, 1999; Campbell et al., 2001).
Although fungal dominance is commonly assumed in no-till soils, the relative
abundance of fungi over bacteria is not consistently greater in the Northern
Great Plain soils under long-term no-till practices compared with intensive
tillage (Helgason et al., 2009).
Using NT and/or cover crop systems can alter enzymatic activity
(Bandick and Dick 1999; Dick 1994), microbial biomass (Linn and Doran
1984; Wagner et al., 1995; Kirchner et al., 2003; Zablotowicz et al., 1998a),
microbial community structure (Lupwayi et al., 1998; Feng et al., 2003), and
macroflora diversity (Gaston et al., 2003; Reeleder et al., 2006).
exä|xã Éy _|àxÜtàâÜx
23
Results of many researchers indicated the importance of reducing tillage as a
means of increasing soil biological activity of the topsoil. (Zibilske & Bradford,
2003; Mijangos, et al., 2006; M̧ ler et al., 2009). Authors have shown that
even a reduction in tillage leads to increased microbial activity and biomass in
contrast to surface soil under conventional tillage (Von Lu zow et al., 2002).
Alternation to no tillage or increased cropping intensity increases microbial
biomass C (MBC) in response to increase nutrient reserves and improved soil
structure and water retention (Biederbeck et al., 2005).
The microbial diversity, measured by the Shannon diversity index (SDI),
was significantly higher in samples from no-tillage system plots in four
taxonomic levels (order, family, genus and species), which agree with Ceja-
Navaro et al. (2010), who found that soils under no-tillage had the highest levels of
microbial diversity compared to the conventional tillage system.
2.2 Conservation agriculture production system (CAPS) - Yield
In the Douglas-Daly and Katherine districts of the Northern Territory,
dryland crops of maize, sorghum, soybean and mungbean sown using no- tillage
with adequate vegetative mulch on the soil surface have produced yields
comparable with, or higher than (especially in drier years), those obtained
under conventional tillage (Thiagalingamb et al., 1996).
Tarkalsona et al. (2006) reported that application of NT system in a long term
period led to indicative improvement in wheat productivity in comparison with CT
system.
exä|xã Éy _|àxÜtàâÜx
24
Shams-Abadi and Rafiee (2007) resulted that using MT, leads to increase
wheat production. Higher yields obtained in conservation agriculture through better
water use and improved soil quality. (Mrabet, 2000).
At Pinnarendi in a similar environment under semi-commercial conditions,
but where surface mulch was apparently not sufficient to reduce soil temperature and
weeds were poorly controlled, yields of peanut, maize and sorghum were lower
under no-tillage than under reduced tillage (Cogle et al., 1995)
Lal (1991) reported from two studies of 8 years or more that larger
maize grain yields were maintained with a mulch based no tillage system than
with a plough based system.
`tàxÜ|tÄá tÇw `xà{Éwá
25
MATERIALS AND METHODS
Conservation agriculture practices with the three components of reduced
tillage, residue retention and crop rotation have potential benefits on soil health that
has been well documented. However, the results vary due to soil type, cropping
system, residue management and climate. A long term field experiment has been
initiated during 2011 at the Regional Research and Technology Transfer Station
(RRTTS) of OUAT, Kendujhar located under the rainfed agro-ecosystem of the North
Central Plateau zone of Odisha (Fig.3.1) and the programme is a joint collaboration of
Orissa University of Agriculture and Technology and University of Hawaii, USA
named ‘SMARTS’ (Sustainable Management of Agricultural Resources for Tribal
Societies). The impact of Conservation Agriculture Production System (CAPS) at the
end of 3rd cropping cycle was assessed in this study with the following materials and
methods.
3.1. MATERIALS
3.1.1 Description of the study area
The experimental site is located in ‘B’ block of RRTTS Kendujhar (Fig. 3.2)
(85˚ 34’ 30.61” E, 20˚ 50’ 55.38”N, 499m above MSL) and the tract is under Agro
Ecological Sub-region (AESR) 12.3 and North Central Plateau Agro-climatic zone of
Odisha. The soils of the experimental sites developed from colluvial-alluvial deposits
in piedmont plain with sandy clay loam to sandy loam texture and belong to Fluventic
Haplustepts as per soil taxonomy.
`tàxÜ|tÄá tÇw `xà{Éwá
26
Fig. 3.1. Agroclimatic zones of Odisha
RRTTS, Keonjhar
North Central
Plateau Zone
`tàxÜ|tÄá tÇ
w `xà{Éwá
26
`tàxÜ|tÄá tÇw `xà{Éwá
27
STUDY AREA WITH PROFILE SITE AND EXTERNAL LAND FEATURES
Fig. 3.2. Study area with profile site and external land features
`tàxÜ|tÄá tÇ
w `xà{Éwá
27
`tàxÜ|tÄá tÇw `xà{Éwá
28
3.1.2. Climate and weather parameter
The climate of the study area is hot, moist, sub-humid with average annual
rainfall of 1527.3mm and more than 75% of the rainfall is received in the months
from May to September. The mean maximum and minimum temperatures are 31.3˚C
and 19.5˚C, respectively and the afternoon relative humidity varies from 34.7% in
March to 87.5% in September.
The weather parameters during growing season of the study year are presented
in Table 3.1 and Fig. 3.3 and 3.4.
Table 3.1 Mean monthly meteorological data during the cropping season (2013 –2014)
Month Mean
Monthly Rainfall (mm)
Rainy Days
Mean monthly Temperature (0C)
Mean Monthly Relative Humidity (%)
Max. Min. FN AN
2013 April 52.7 5 36.66 20.06 65.3 29.1 May 35.0 3 39.16 23.96 83.8 29.8 June 312.7 16 32.20 21.93 82.8 48.5 July 277.9 18 30.71 22.41 87.1 57.9 August 253.0 13 30.16 22.83 87.3 58.6 September 196.6 14 30.80 21.90 87.8 59.5 October 296.0 14 28.03 19.29 91.9 70.6 November 1.1 0 27.93 13.53 79.5 43.5 December 0 0 26.29 9.41 77.7 38.0 2014 January 0 0 26.70 10.00 76.5 34.2 February 46.3 3 29.25 11.93 65.2 26.8 March 26.7 2 31.96 16.38 62.2 23.7
3.1.3 Experimental design and Treatment details
The design of the experiment is split-plot with three replications. The treatment
details are conventional (CT) and minimum (MT) tillage with maize
`tàxÜ|tÄá tÇw `xà{Éwá
29
Fig. 3.3 Mean monthly rainfall and rainy days during the cropping season (April 2013 – March 2014)
Fig. 3.4 Mean monthly temperature and relative humidity data during the cropping season (April 2013 – March 2014)
0
2
4
6
8
10
12
14
16
18
20
0
50
100
150
200
250
300
350
April May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March
No
. o
f D
ay
s
Ra
infa
ll (
mm
)
Month
Rainfall (mm) Rainy days
0
10
20
30
40
50
60
70
80
90
100
5
15
25
35
45
55
65
75
April May June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. March
Re
lati
ve
Hu
mid
ity
(%
)
Tem
pe
ratu
re (◦C
)
Month
Min. Temp. Max. Temp. AN R.H. FN
`tàxÜ|tÄátÇw`xà{Éwá
30
RI RII RIII
CT-M-NCC
MT-M+C-T
MT-M-H
MT-M+C-H
CT-M-T
CT-M+C-NCC
CT-M-H MT-M+C-NCC MT-M-NCC MT-M+C-T CT-M-H CT-M+C-T
CT-M-T MT-M+C-H MT-M-T MT-M+C-NCC CT-M-NCC CT-M+C-H
MT-M-NCC CT-M+C-H CT-M-T CT-M+C-NCC MT-M-T MT-M+C-H
MT-M-H CT-M+C-NCC CT-M-H CT-M+C-T MT-M-H MT-M+C-NCC
MT-M-T CT-M+C-T CT-M-NCC CT-M+C-H MT-M-NCC MT-M+C-T
Fig. 3.3 Layout plan of the experiment
Main plot (Kharif) Sub plot (Rabi)
Experimental Design: Split plot CT-M - Conventional til lage with sole maize NCC-No cover crop Number of treatments: 12 CT-M+C - Conventional tillage with maize +cowpea T-Toria Number of replication: 03 MT-M - Minimum tillage with sole maize H-Horse gram Individual plot size: 7.2m43.2m MT-M+C - Minimum tillage with maize + cowpea
`tàxÜ|tÄá tÇ
w `xà{Éwá
30
N
`tàxÜ|tÄá tÇw `xà{Éwá
31
sole (M) and maize cowpea intercrop (M+C) in main plots during wet season
(Kharif) and no cover crop (NCC), horse gram (HG) and toria mustard (T) in sub-
plots during dry season (Rabi), resulting a total of twelve different combinations.
The treatment details and layout design are depicted in Table3.2 and Figure3.5
respectively.
Table 3.2. Treatment details
Treatment Descriptions
Main plot ( Kharif season)
CT-M Conventional tillage with sole maize
CT-M+C Conventional tillage with maize + cowpea
MT-M Minimum tillage with sole maize
MT-M+C Minimum tillage with maize + cowpea
Sub-plot (Rabi season)
NCC No cover crop
HG Horsegram as cover crop
TORIA Toria as cover crop
3.1.4 Field preparation
The conventional tillage (CT) involves three mould board ploughing without
residue to a depth of 20-25 cm and in minimum tillage (MT), one shallow disking is done
up to a depth of 10 cm with addition of chopped main crop (maize, cowpea) and cover crop
(horsegram, toria) biomass as surface residues.
3.1.5 Crop management
The crop varieties used in the experiment, their duration, date of sowing as
well as harvesting is given below.
`tàxÜ|tÄá tÇw `xà{Éwá
32
Fig. 3.6 Representative Pedon of the experimental site
Order- Inceptisol
Sub-oder- Ustepts
Great group- Haplustepts
Sub-group- Fluventic Haplustepts
Fig.3.8. Site features around the pedon site
Fig.3.7. Many coarse and medium lime nodules
`tàxÜ|tÄá tÇw `xà{Éwá
33
Table 3.3 Crop varieties and their duration
Crops Variety Duration
Maize Pioneer 30R-77 90-100days
Cowpea Utkalmanika 75days
Horsegram Athagarh local
100days
Toria (Mustard) Anuradha 75-80days
3.1.6 Fertilizer management
The recommended chemical fertilizers applied to Maize, Cowpea, Toria and
Horsegram were indicated in the Table 3.4. The fertilizer applied for Maize +
Cowpea was based on additive series, taking into consideration 100 per cent
plant population of maize and 50 percent plant population of cowpea. The fertilizers
were applied i n l i n e basally for the crops except maize where nitrogen was applied
in three split viz. 25% basal, 50% at first earthing up and rest 25% at second
earthing up stage.
Table3.4 Fertilizer dose for different experimental crops grown
Crops
Fertilizer Dose (kg ha-1)
N P2O5 K2O
Maize 80 40 40
Cowpea 20 40 20
Mustard 40 20 20
Horsegram 20 40 20
3.1.7 Sowing, Seedrate and Spacing
During kharif season, for sole maize, spacing of 60cmx30cm was adopted
for which a seed rate of 15kg ha-1 was required. But, maize + cowpea as intercrops
were sown in 1:1 ratio at a uniform spacing of 30cm. The spacing adopted for
`tàxÜ|tÄá tÇw `xà{Éwá
34
cowpea was 15cm from plant to plant within the row. A seed rate of 10 kg ha-1 was
required taking into consideration that the cowpea plant population was 50% of
normal sole cowpea. In Minimum tillage practice, Maize and Cowpea seeds
were sown by dibbling in line. In Conventional tillage practice, line sowing of
seeds was done and the seeds were covered with soil after sowing. A seed rate of
7.5kg and 25 kg ha-1was required for toria and horsegram, respectively.
3.2 METHODS
3.2.1 Collection and processing of soil samples
Soil samples were collected after harvest of the cover crops in the month of
February, 2014.
Soil samples from each plot consisted of composite samples that were
collected with a narrow spade and divided into segments of 0-5, 5-10 and 10-20cm,
placed in plastic bags and brought to the laboratory immediately for analysis. Field
moist samples were gently passed through a 10mm sieve and dried at 40˚C for 48
hours and 100g of dry soil samples were used for determining water stable aggregates.
A portion of fresh soil samples were sieved through a 2mm sieve and stored at 4˚C for
analysis of various microbiological tests. Another portion of the sieved soils were air
dried (2-3 days) and used for determination of organic carbon and pH. Undisturbed
core samples from each layers were collected with a core sampler (5.0cm diameter)
for determination of soil bulk density. Soil cores from each depth were also collected
during sowing, flowering and harvesting of dry season cover crops for determination
of gravimetric moisture content.
`tàxÜ|tÄá tÇw `xà{Éwá
35
Fig.3.9. Wet-sieving of Water stable aggregates Fig.3.10. CH3Cl Fumigation for MBC
Fig. 3.11. Actinomycetes population in both CT and MT type of cropping systems
Fig.3.12. Maize stalk and residue incorporation in MT system
`tàxÜ|tÄá tÇw `xà{Éwá
36
3.2.2 Methods of Soil Analysis
a) Physical analysis
3.2.2.1 Bulk density
The bulk density of the soils from the experimental plots was analysed by core
method (Blake, 1965).
3.2.2.2 Water stable aggregates (WSA)
The WSA in the soils were determined using 250µm and 53µm mesh sieve
by wet sieving method (Kemper and Rosenau,1986). A sample of 100g air-dried (8-
mm sieved) soil was placed on the top of a 2-mm sieve and submerged for 5 min in
deionized water at room temperature to allow slaking (Kemper and Rosenau, 1986).
Sieving was manually done (when the sample was submerged) by moving the sieves up
and down 3 cm, 50 times in 2 min to achieve aggregate separation. A series of two sieves
(0.25 and 0.053 mm) was used to obtain the two aggregate fractions: (1) 0.25–2-mm
(macro-aggregates), (2) 0.053–0.25-mm (micro-aggregates). Soil aggregate fractions
retained on different sieves, were oven dried (500C), weight expressed in percentages.
3.2.2.3 Soil Moisture Content (SMC)
The SMC in the soils were determined by gravimetric method. The soil
samples are collected and dried in the hot air oven at 105˚C for 24 hours. Moisture
content is determines by measuring moist weight and dry weight of the soil. It is
expressed as percentage of moisture content per weight of dry soil (Dastane, 1972).
b) Chemical analysis
3.2.2.4 Soil pH
As suggested by Jackson (1973) the pH of soil samples of the
experimental plots was determined in 1:2.5 soil:water suspension after equilibration
`tàxÜ|tÄá tÇw `xà{Éwá
37
for half an hour with intermittent stirring using the glass electrode digital pH meter,
‘SYSTRONICS’ (modelM.K.VI).
3.2.2.5 Organic carbon
The organic carbon of soils of representative pedon and experiment was
determined by modified Walkley and Black’s rapid titration method (Jackson,
1973) using Ferroin indicator (Chopra and Kanwar, 1986).
c) Microbial analysis
3.2.2.6 Enumeration of soil microbial population
Soil microbial population was determined by serial dilution and spread plate
technique. One gram of the soil sample was added to test tube containing 9 ml of distilled
water, serially diluted (Dhingra and Sinclair, 1993) spread over Nutrient Agar,
Actinomycetes Isolation Agar and Potato Dextrose Agar for enumeration of bacteria,
actinomycetes and fungi, respectively. The plates were incubated at 30˚C for 24 hours
for bacterial isolation and at 30˚C for 48 hours for actinomycetes and fungal isolation.
Calculation
The following mathematical deduction was followed for enumeration of the
microbial colony and expressed as CFU per gram of soil.
CFU/ml = No. of colony Inverse of dilution taken
Volume of inoculum taken
×
3.2.2.7 Soil microbial biomass carbon
Microbial biomass carbon was estimated employing fumigation and
extraction procedure as described by Vance et al.,(1987). The process
involved collection of filtrate using Whatman filter paper no.2 by shaking
unfumigated soil (20 g) with 0.5 M K2SO4 for 30 minutes. Similarly another set
`tàxÜ|tÄá tÇw `xà{Éwá
38
of filtrate was collected using fumigated soil exposed to ethanol free
chloroform for 24 hours. Organic carbon in both the extract was analyzed using
the method of digestion titration. For digestion of organic carbon 10 ml of
filtrate was transferred into a conical flask and 10 ml of K2Cr2O7 followed
by 20 ml of conc. H2SO4 were added and the entire content was digested for
30 minutes at 1700C .After the content in the flask cooled down, 25 ml
distilled water and 5 ml, ortho-phosphoric acid were added to the digested
material and titrated against 0.04 M Ferrous ammonium sulphate with
Ferroin as the indicator.
Calculation
Microbial biomass carbon = EC fumigated soil - EC of unfumigated soil
Kc
where, EC = Extractractable carbon
Kc = 0.379 (Kc is the K2SO4 extract efficiency factor (Hu and Cao, 2007)
3.2.2.8 Maize-equivalent yield
Maize equivalent yield (MEY) was calculated by the formula as follows :
MEY (q/ha) = Yield of other crop produce (q/ha) price of that produce(Rs/q)
Price of maize grain (Rs/q)
×
The maize equivalent yield of the cropping system was obtained by addition
of yield of maize component and the maize equivalent yield of other component
crop taken in intercropping and the Rabi crop if any (toria and horsegram).
3.2.2.9 Statistical analysis
Data in respect of soil physical and chemical properties for various
treatments were subjected to analysis of variance following standard statistical
procedure (Gomez and Gomez, 1984).
exáâÄàá
39
RESULTS
The impact of Conservation Agricultural Production System (CAPS)
involving tillage methods and cropping systems (intercrop, cover crop) on soil health
has been assessed after three cropping years in the present study. Results pertaining to
some of the major soil physical, chemical and biological parameters influenced by
adoption of CAPS, have been described in this section.
4 SOIL PARAMETERS OF THE EXPERIMENT
4.1 SOIL PHYSICAL PARAMETERS
4.1.1 Bulk Density (BD)
Soil Bulk Density is one of the most common variables used to assess soil
physical properties. Conventional and minimum tillage with cropping systems like sole
or intercrop of maize and follow-up cover crops affected the soil BD (Table 4.1,
Fig.4.1)significantly across the soil profile at the end of third cropping cycle. Practice of
minimum tillage (MT) reduced the soil BD in the tune of 3.4% and 2.6% over the initial
values (1.32 and 1.37 Mg m-3) in 0-5 and 5-10 cm depths, respectively, whereas, these
soils under conventional tillage (CT) registered higher BD (+1.5%, + 2.2%).Cover
cropping (HG, TORIA) also lowered the soil BD by 1.3% and 1.0% in the depth ranges
of 0-5 cm and 5-10 cm, respectively over the soil under NCC (1.32 and 1.38 Mg m-3).
For 10-20 cm range, no significant variation in soil BD was observed among different
treatments.
exáâÄàá
40
Table 4.1 Soil BD (Mg m-3) as influenced by CAPS
0-5 cm layer
Particulars NCC HG TORIA Mean
CT-M 1.38 1.35 1.36 1.36 CT-M+C 1.34 1.32 1.31 1.32 MT-M 1.29 1.28 1.29 1.28 MT-M+C 1.28 1.26 1.28 1.27 Mean 1.32 1.30 1.31 Initial 1.32
M S M within S S within M SEm(±) 0.010 0.003 0.012 0.007
CD (0.05) 0.04 0.01 NS NS
5-10cm layer
Particulars NCC HG TORIA Mean
CT-M 1.42 1.41 1.40 1.41 CT-M+C 1.41 1.38 1.39 1.39 MT-M 1.35 1.33 1.34 1.34 MT-M+C 1.34 1.32 1.33 1.33 Mean 1.38 1.36 1.36 Initial 1.37
M S M within S S within M
SEm(±) 0.007 0.003 0.009 0.007
CD (0.05) 0.02 0.01 NS NS
10-20cm layer
Particulars NCC HG TORIA Mean
CT-M 1.47 1.45 1.46 1.46 CT-M+C 1.46 1.44 1.44 1.45 MT-M 1.46 1.45 1.44 1.45 MT-M+C 1.45 1.44 1.44 1.45 Mean 1.46 1.45 1.45 Initial 1.44
M S M within S S within M
SEm(±) 0.009 0.004 0.011 0.009
CD (0.05) NS NS NS NS
exáâÄàá
41
Fig. 4.1 Soil BD (Mg m-3) as influenced by CAPS. Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
1.22
1.24
1.26
1.28
1.3
1.32
1.34
1.36
1.38
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
1.32
a
b
cc
a
cb
BD
(M
g m
-3)
Treatments
0-5 cm
1.28
1.3
1.32
1.34
1.36
1.38
1.4
1.42
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
1.37
a
b
c
c
a
b b
BD
(M
g m
-3)
Treatments
5-10 cm
1.43
1.44
1.45
1.46
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
1.44
NS
NSNS
NS
NS
NS NS
BD
(M
g m
-3)
Treatemnts
10-20 cm
exáâÄàá
42
4.1.2 Water Stable Aggregates
Aggregate measurement is very often used as surrogates of the complex soil
matrix for studies of soil organic matter dynamics.
4.1.2.1 Macro-aggregates (>0.25mm)
The organic binding by-products resulting from accumulation of organic matter
in the surface layers (0-5 cm) significantly increased the water stable macro-aggregated
in different MT treatments. The data pertaining to macro-aggregates in different layers
are depicted in Table 4.2a. and Fig.4.2a. Practices of MT resulted in significant increase
in proportion of macro-aggregates in 0-5 cm and 5-10 cm layers and the gain was in the
tune of 14.9% and 11.9%, respectively, over the initial values (58.2%, 52.88%). Soils
under CT in these two top layers exhibited a reduction of macro-aggregates by 5.3% and
5.7%. The soils in the layer of 10-20 cm did not show any variation in macro-aggregates
among different treatments. Treatments with cover crops elevated the status of macro-
aggregates in the tune of 7.2% and 4.9% in the two top layers over NCC at the end of
the 3rd cropping year.
4.1.2.2 Micro-aggregates (0.053 – 0.25 mm)
Tillage reduction and residue retention decreases the proportion of micro-
aggregates in the soil because of slower turnover of macro-aggregates. The proportion of
micro-aggregates under MT treatments was distinctly reduced by 14.8% and 14.5% in 0-
5 cm and 5-10 cm layers (Table 4.2b. and Fig.4.2b.) over the initial value of 17.7% and
19.2%, respectively. The concomitant increase of micro-aggregates in the soils under CT
treatments was 5.9% and 4.3% for the top two layers. The bottom layers (10-20 cm) of
both MT and CT exhibited no noticeable variation in the proportion of micro-aggregates
(Table 4.2b). Treatments with cover crops could not influence the status of micro-
aggregates much.
exáâÄàá
43
Table 4.2a. Effect of CAPS on water stable macro-aggregates (>0.25mm) (%)
0-5cm layer
Particulars NCC HG TORIA Mean CT-M 52.88 56.67 53.99 54.51 CT-M+C 52.80 57.39 56.92 55.70 MT-M 62.16 67.29 65.37 64.94 MT-M+C 64.86 72.03 69.93 68.94 Mean 58.17 63.34 61.55 Initial 58.22 M S M within S S within M SEm(±) 1.269 1.087 2.182 2.174 CD (0.05) 4.39 3.17 NS NS
5-10cm layer
Particulars NCC HG TORIA Mean CT-M 46.08 50.24 49.94 48.75 CT-M+C 48.06 52.63 51.76 50.82 MT-M 57.47 59.07 58.96 58.50 MT-M+C 58.39 61.13 59.77 59.76 Mean 52.50 55.76 55.11 Initial 52.82
M S M within S S within M SEm(±) 1.538 1.096 2.360 2.192
CD (0.05) 5.32 NS NS NS
10-20cm layer Particulars NCC HG TORIA Mean
CT-M 39.86 43.70 42.87 42.15 CT-M+C 42.86 44.38 43.67 43.64 MT-M 44.36 47.52 46.56 46.15 MT-M+C 44.42 47.31 46.39 46.04 Mean 42.88 45.73 44.87 Initial 44.72 M S M within S S within M SEm(±) 0.900 1.244 2.221 2.487
CD (0.05) NS NS NS NS
exáâÄàá
44
Fig. 4.2a. Effect of CAPS on water stable macro-aggreagtes (>0.25 mm) Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05.
58.2b b
aa
b
a a
0
10
20
30
40
50
60
70
80
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
WS
A (
> .
25
0 m
m)
[%]
Treatments
0-5 cm
52.8b b
a a
NSNS NS
0
10
20
30
40
50
60
70
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
WS
A (
> .
25
0 m
m)
[%]
Treatments
5-10 cm
44.72
NS
NS
NS NS
NS
NS
NS
40
41
42
43
44
45
46
47
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
WS
A (
> .
25
0 m
m)
[%]
Treatments
10-20 cm
exáâÄàá
45
Table 4.2b. Effect of CAPS on water stable micro-aggregates (0.053-0.25 mm)(%)
0-5cm layer
Particulars NCC HG TORIA Mean
CT-M 20.72 18.27 19.57 19.52 CT-M+C 18.20 16.75 17.05 17.33 MT-M 15.97 15.48 15.83 15.76 MT-M+C 14.57 13.58 13.60 13.92 Mean 17.37 16.02 16.51 Initial 16.16
M S M within S S within M SEm(±) 0.506 0.654 1.182 1.308
CD (0.05) 1.75 NS NS NS
5-10cm layer
Particulars NCC HG TORIA MEAN
CT-M 23.57 19.36 21.05 21.33 CT-M+C 19.00 18.38 18.63 18.67 MT-M 17.91 16.35 17.15 17.14 MT-M+C 16.25 15.14 15.69 15.69 Mean 19.18 17.31 18.13 Initial 18.10
M S M within S S within M SEm(±) 0.506 0.621 1.133 1.241
CD (0.05) 1.75 NS NS NS
10-20cm layer
Particulars NCC HG TORIA Mean
CT-M 23.77 22.98 23.60 23.45 CT-M+C 22.47 20.75 21.99 21.73 MT-M 20.94 20.45 20.70 20.70 MT-M+C 20.31 19.61 20.24 20.05 Mean 21.87 20.95 21.63 Initial 19.60
M S M within S S within M
SEm(±) 0.708 0.709 1.357 1.418
CD (0.05) NS NS NS NS
exáâÄàá
46
Fig. 4.2b. Effect of CAPS on water stable micro-aggregates (0.053-0.25mm).Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05.
0
5
10
15
20
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
16.16
a
bb
c
NSNS NS
WS
A (
0.0
53
-0.2
50
mm
) [%
]
Treatments
0-5 cm
0
5
10
15
20
25
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
18.1
a
bbc
c
NSNS
NS
WS
A (
0.0
53
-0.2
50
mm
) [%
]
Treatments
5-10 cm
17
18
19
20
21
22
23
24
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
19.6
NS
NS
NS
NS
NS
NS
NS
WS
A (
0.0
53
-0.2
50
mm
) [%
]
Treatments
10-20 cm
exáâÄàá
47
4.1.3 Gravimetric Water Content (w)
The gravimetric water content across the soil profile differed significantly among
the sampling time, registering higher values at sowing that went on decreasing during
flowering and harvesting time of cover crops. The surface layer (0-5 cm) under MT
treatments exhibited significantly higher water contents both at sowing (16.5%) and
flowering (11.9%) as compared to that of CT treatments ( 14.7% and 10.5%) (Table 4.3a
i. and ii.). There was no significant variation in water contents in the surface layer during
harvesting (Table 4.3a iii.). The water contents in 5-10 cm layer (Table 4.3b) and 10-20 cm
layer (Table 4.3c) did not change significantly among treatments during each sampling time.
However, an increase in overall water contents across the profile was observed at the end of
3rd cropping cycle. In general, an increasing trend in the water contents was observed down
the depth irrespective of treatments and sampling time (Fig.4.3).
Table 4.3a(i,ii,iii) Effect of CAPS on soil moisture content (%) at 0-5cm depth 0-5cm layer
Sowing (4.3a i) Particulars NCC HG TORIA Mean
CT-M 14.23 15.24 14.52 14.67 CT-M+C 14.44 14.83 14.63 14.63 MT-M 16.03 16.35 16.29 16.22 MT-M+C 16.44 16.83 16.88 16.72 Mean 15.29 15.81 15.58 Initial 14.33 M S M within S S within M SEm(±) 0.487 0.186 0.575 0.373 CD (0.05) 1.687 NS NS NS
Flowering (4.3a ii) Particulars NCC HG TORIA Mean
CT-M 10.22 10.54 10.42 10.39 CT-M+C 10.27 10.68 10.57 10.51 MT-M 11.75 11.99 11.93 11.89 MT-M+C 11.66 12.09 12.00 11.92 Mean 10.98 11.33 11.23 Initial 10.2 M S M within S S within M SEm(±) 0.384 0.136 0.444 0.272 CD (0.05) 1.329 NS NS NS
exáâÄàá
48
Harvesting (4.3a iii) Particulars NCC HG TORIA Mean CT-M 7.14 7.53 7.33 7.33 CT-M+C 7.34 7.64 7.54 7.51 MT-M 7.61 7.94 7.83 7.79 MT-M+C 7.54 7.93 8.14 7.87 Mean 7.41 7.76 7.71 Initial 7.27 M S M within S S within M SEm(±) 0.361 0.231 0.523 0.463 CD (0.05) NS NS NS NS
Table 4.3b. Effect of CAPS on soil moisture content (%) at 5-10cm depth
5-10cm layer Sowing
Particulars NCC HG TORIA Mean CT-M 14.92 15.74 15.83 15.50 CT-M+C 15.46 15.81 15.80 15.69 MT-M 16.82 17.06 17.00 16.96 MT-M+C 16.90 17.39 17.35 17.21 Mean 16.02 16.50 16.50 Initial 14.96 M S M within S S within M SEm(±) 0.530 0.159 0.589 0.317 CD (0.05) NS NS NS NS
Flowering Particulars NCC HG TORIA Mean CT-M 10.70 11.04 11.20 10.98 CT-M+C 11.02 11.22 11.34 11.19 MT-M 12.29 12.48 12.67 12.48 MT-M+C 12.28 12.76 12.69 12.58 Mean 11.57 11.88 11.98 Initial 10.73 M S M within S S within M SEm(±) 0.456 0.150 0.518 0.301
CD (0.05) NS NS NS NS
Harvesting Particulars NCC HG TORIA Mean CT-M 7.53 8.13 7.80 7.82 CT-M+C 7.64 7.94 7.84 7.81 MT-M 8.24 8.60 8.52 8.45 MT-M+C 8.18 9.02 8.83 8.68 Mean 7.90 8.42 8.25 Initial 7.55 M S M within S S within M SEm(±) 0.337 0.163 0.429 0.327 CD (0.05) NS NS NS NS
exáâÄàá
49
Table 4.3c. Effect of CAPS on soil moisture content (%) at 10-20cm depth 10-20cm layer
Sowing
Particulars NCC HG TORIA Mean
CT-M 15.86 16.51 16.40 16.26 CT-M+C 16.08 16.63 16.47 16.39 MT-M 16.89 17.54 17.50 17.31 MT-M+C 17.03 17.74 17.51 17.43 Mean 16.47 17.10 16.97 Initial 15.96
M S M within S S within M
SEm(±) 0.300 0.260 0.519 0.519
CD (0.05) NS NS NS NS
Flowering
Particulars NCC HG TORIA Mean
CT-M 11.51 11.74 12.00 11.75 CT-M+C 11.82 12.03 12.22 12.02 MT-M 12.39 12.67 12.89 12.65 MT-M+C 12.48 12.78 12.95 12.74 Mean 12.05 12.31 12.52 Initial 11.52
M S M within S S within M
SEm(±) 0.315 0.214 0.471 0.429
CD (0.05) NS NS NS NS
Harvesting Particulars NCC HG TORIA Mean CT-M 7.82 8.30 8.13 8.08 CT-M+C 7.84 8.28 8.20 8.11 MT-M 8.79 9.13 9.02 8.98 MT-M+C 9.04 9.30 9.20 9.18 Mean 8.37 8.75 8.64 Initial 7.79
M S M within S S within M
SEm(±) 0.295 0.212 0.455 0.425
CD (0.05) NS NS NS NS
exáâÄàá
50
Fig.4.3 Periodical soil moisture content across the profile
10
14
18
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
So
il M
ois
ture
Co
nte
nt
(%)
Treatments
SOWING0-5 cm 5-10 cm 10-20 cm
6
8
10
12
14
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
So
il M
ois
ture
Co
nte
nt
(%)
Treatments
FLOWERING0-5 cm 5-10 cm 10-20 cm
6
8
10
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
So
il M
ois
ture
Co
nte
nt
(%)
Treatments
HARVESTING0-5 cm 5-10 cm 10-20 cm
exáâÄàá
51
4.2 SOIL CHEMICAL PARAMETERS
4.2.1 Soil Reaction (pH)
The nutrient dynamics and microbial profile of a soil are influenced by soil
reaction, hence, it is considered as an important soil quality indicator.
The pH of the soils across the profile is presented in Table 4.4 and Fig.4.4.
Tillage with cropping systems did not influence the soil pH except the layers of 0-5cm.
The soil pH in the surface layer under MT system was reduced by 3.7% and 1.5%, over
the initial status (7.34) and that under CT system (7.18), respectively. Though the soil
pH did not exhibit any significant variation in the layers of 5-10 and 10-20cm, a
decreasing trend was observed in the soils under MT systems.
Table 4.4 Effect of CAPS on soil pH (1:2.5) 0-5cm layer
Particulars NCC HG TORIA Mean CT-M 7.22 7.17 7.17 7.19 CT-M+C 7.20 7.14 7.15 7.16 MT-M 7.10 7.07 7.09 7.09 MT-M+C 7.09 7.02 7.03 7.05 Mean 7.15 7.10 7.11 Initial 7.34 M S M within S S within M SEm(±) 0.029 0.033 0.061 0.066 CD (0.05) 0.1 NS NS NS
5-10cm layer Particulars NCC HG TORIA Mean CT-M 7.56 7.53 7.54 7.54 CT-M+C 7.57 7.50 7.51 7.53 MT-M 7.53 7.47 7.48 7.50 MT-M+C 7.53 7.46 7.48 7.49 Mean 7.55 7.49 7.50
Initial 7.46
M S M within S S within M SEm(±) 0.030 0.034 0.062 0.067
CD (0.05) NS NS NS NS
exáâÄàá
52
10-20cm layer Particulars NCC HG TORIA Mean CT-M 7.60 7.59 7.59 7.59 CT-M+C 7.62 7.61 7.62 7.62 MT-M 7.61 7.51 7.51 7.54 MT-M+C 7.54 7.58 7.57 7.56 Mean 7.59 7.58 7.57 Initial 7.51 M S M within S S within M SEm(±) 0.027 0.038 0.034 0.026 CD (0.05) NS NS NS NS
Fig.4.4 pH of soils of 0-5cm depth as influenced by CAPS.Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05.
4.2.2 Soil Organic Carbon (SOC)
Elevation in soil organic carbon due to residue retention and minimum soil
disturbances is related to physical protection of C in better preserved macro-aggregates
under MT systems. Distribution of SOC across the profile was presented in Table 4.5
and Fig.4.5. The SOC contents under MT treatments increased significantly (+27.9%
and +15.2%) over the initial status of 6.82 and 6.44 g kg-1 in the top two layers of
6.9
7
7.1
7.2
7.3
7.4
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
7.34
aab
bc
c
a
b b
pH
Treatments
0-5 cm
exáâÄàá
53
0-5and 5-10 cm. A reduction of SOC (-9.8% and -15.7%) was observed in CT
treatments for the same layers. The contribution of cover crops to SOC pool in the tune
of 13.0% and 2.6% over NCC (6.88 and 6.06 g kg-1) was also observed in the top layers
of 0-5 cm and 5-10 cm. The SOC contents under both CT and MT treatments did not
show any significant variations in the deeper layer of 10-20 cm.
Table 4.5 Soil Organic Carbon (g kg-1) as influenced by CAPS
0-5cm layer Par ticulars NCC HG TORIA Mean
CT-M 5.19 6.27 5.89 5.78 CT-M+C 6.38 6.71 6.43 6.51 MT-M 7.69 9.04 8.35 8.36
MT-M+C 8.26 9.95 9.05 9.08 Mean 6.88 7.99 7.43 Initi al 6.82
M S M within S S within M SEm (±) 0.139 0.110 0.227 0.221 CD(0.05) 0.48 0.32 NS
5-10cm layer Particulars NCC HG TORIA MEAN CT-M 4.79 5.49 5.35 5.21 CT-M+C 5.52 5.75 5.65 5.64 MT-M 6.68 7.45 7.15 7.09 MT-M+C 7.15 8.12 7.94 7.74 Mean 6.04 6.70 6.52 Initial 6.44 M S M within S S within M SEm(±) 0.137 0.094 0.205 0.188 CD (0.05) 0.47 0.27 NS NS
10-20cm layer Particulars NCC HG TORIA Mean CT-M 4.62 4.75 4.65 4.67 CT-M+C 4.76 4.85 4.80 4.80 MT-M 4.79 4.88 4.84 4.84 MT-M+C 4.86 5.24 5.14 5.08 Mean 4.76 4.93 4.86 Initial 4.72 M S M within S S within M SEm(±) 0.087 0.060 0.131 0.119 CD (0.05) NS NS NS NS
exáâÄàá
54
Fig. 4.5 Soil Organic Carbon (g kg-1) as influenced by CAPS.Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
0
2
4
6
8
10
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
6.82
dc
ab
c
ab
Org
an
ic C
arb
on
(g
kg
-1)
Treatments
0-5 cm
0
1
2
3
4
5
6
7
8
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
6.44
cc
ba
ba a
Org
an
ic C
arb
on
(g
kg
-1)
Treatments
5-10 cm
4.4
4.5
4.6
4.7
4.8
4.9
5
5.1
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
4.72NS
NSNS
NS
NS
NS
NS
Org
an
ic C
arb
on
(g
kg
-1)
Treatments
10-20 cm
exáâÄàá
55
4.3 SOIL MICROBIAL ATTRIBUTES
Gradual build up and restoration of SOC under reduced tillage system elevated
the microbial population and microbial biomass carbon (MBC) significantly in the
surface layers.
4.3.1 Microbial Population
4.3.1.1 Population of Bacteria
The population of bacteria in different layers was enhanced as compared to the
initial status at the end of the 3rd cropping year (Table 4.6). In the surface layer (0-5 cm)
an increase of 61.2% and 23.0% over the initial population of 17.6 × 106cfu g-1 was
observed in MT and CT treatments (Fig.4.6a), respectively. Similar trend was also
observed in the layer of 5-10 cm (Fig.4.6b) and no significant changes in bacterial
population could be noticed among treatments below the depth of 10 cm. Higher
amounts of organic matter in MT soils increased the bacterial abundance significantly to
the tune of 31.0% and 25.5% over the CT soils in the top two layers (0-5 cm and 5-10
cm). Again, practice of cover crops enhanced the bacterial proportion by 21.8% and
20.1% over no cover crop treatments (NCC) in the layers of 0-5 cm, and 5-10 cm,
respectively.
Table 4.6 Bacterial population (× 106cfu g-1) as influenced by CAPS
0-5cm layer Particulars NCC HG TORIA Mean CT-M 17.00 21.00 20.67 19.56 CT-M+C 21.33 26.00 23.33 23.56 MT-M 22.67 29.00 28.33 26.67 MT-M+C 26.00 33.00 31.00 30.00 Mean 21.75 27.25 25.83 Initial 17.56 M S M within S S within M SEm(±) 0.485 0.450 0.881 0.900 CD (0.05) 1.68 1.31 NS NS
exáâÄàá
56
5-10cm layer Particulars NCC HG TORIA Mean CT-M 14.33 19.33 18.33 17.33 CT-M+C 20.33 23.00 22.33 21.89 MT-M 21.33 24.67 23.33 23.11 MT-M+C 22.00 28.67 27.67 26.11 Mean 19.50 23.92 22.92 Initial 14.66
M S M within S S within M SEm(±) 0.684 0.710 1.346 1.419
CD (0.05) 2.37 2.07 NS NS
10-20cm layer
Particulars NCC HG TORIA Mean
CT-M 13.83 15.00 14.67 14.50 CT-M+C 14.33 15.67 16.00 15.33 MT-M 14.83 15.83 15.50 15.39 MT-M+C 15.37 16.57 16.20 16.04 Mean 14.59 15.77 15.59 Initial 12.94
M S M within S S within M
SEm(±) 0.337 0.523 0.918 1.046
CD (0.05) NS NS NS NS
4.3.1.2 Population of Fungi
Differential status of organic matter among treatments influenced the population
of fungi in the soil (Table 4.7 and Fig. 4.7). The soils under MT registered the maximum
fungal population and gain was of 36.8% and 28.2% over the initial values (11.8 and 9.4
× 104cfu g-1) in the layers of 0-5 cm and 5-10 cm, respectively. The treatments under CT
also exhibited an increase of 12.1% and 8.1% over the initial status (base year) in the top
two layers. Cover cropping also enhanced the fungal population in the tune of 15.1% in
0-5 cm layer and 13.6% in 5-10 cm layer over NCC treatments. The fungal population in
10-20 cm layer did not show significant changes among various treatments.
exáâÄàá
57
Fig. 4.6a
Fig. 4.6b
Fig. 4.6 Bacterial population (× 106cfu g-1) as by different CAPS. Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05.
10
12
14
16
18
20
22
24
26
28
30
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
17.56
d
c
b
a
c
ab
Ba
cte
ria
po
pu
lati
on
( ×
10
6cf
u g
-1)
Treatments
0-5 cm
10
12
14
16
18
20
22
24
26
28
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
14.66
c
b
b
a
b
aa
Ba
cte
ria
po
pu
lati
on
( ×
10
6cf
u g
-1)
Treatments
5-10 cm
exáâÄàá
58
Table 4.7 Population of fungi (× 104cfu g-1) as influenced by CAPS
0-5cm layer
Particulars NCC HG TORIA Mean
CT-M 11.34 13.64 13.22 12.73 CT-M+C 12.15 14.76 13.94 13.62 MT-M 14.50 16.70 15.81 15.67 MT-M+C 15.18 17.41 17.01 16.53 Mean 13.29 15.63 15.00 Initial 11.77
M S M within S S within M SEm(±) 0.333 0.380 0.705 0.761
CD (0.05) 1.15 1.11 NS NS
5-10cm layer
Particulars NCC HG TORIA Mean
CT-M 9.36 10.21 10.08 9.88 CT-M+C 9.88 10.77 10.67 10.44 MT-M 10.34 12.24 11.89 11.49 MT-M+C 11.24 13.51 13.14 12.63 Mean 10.21 11.68 11.44 Initial 9.44
M S M within S S within M SEm(±) 0.406 0.193 0.514 0.387
CD (0.05) 1.40 0.56 NS NS
10-20cm layer
Particulars NCC HG TORIA Mean
CT-M 8.34 8.67 8.56 8.52 CT-M+C 8.88 9.34 9.27 9.16 MT-M 8.97 9.42 9.24 9.21 MT-M+C 9.26 10.23 10.17 9.89 Mean 8.86 9.42 9.31 Initial 8.37
M S M within S S within M
SEm(±) 0.313 0.218 0.474 0.436
CD (0.05) NS NS NS NS
exáâÄàá
59
Fig. 4.7 Fungal population (× 104cfu g-1) asinfluenced by different CAPS.
Treatments with same lower case letter within main plots or sub-
plots were not significant at P = 0.05.
8
9
10
11
12
13
14
15
16
17
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
11.77
b
b
a
a
b
a
a
Fu
ng
al
po
pu
lati
on
( ×
10
4cf
u g
-1)
Treatments
0-5 cm
6
7
8
9
10
11
12
13
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
9.44
c
bc
ab
a
b
aa
Fu
ng
al
po
pu
lati
on
( ×
10
4cf
u g
-1)
Treatments
5-10 cm
exáâÄàá
60
4.3.1.3 Population of Actinomycetes
The population of actinomycetes under different treatments across the profile
was presented in Table 4.8 and Fig.4.8. Accumulation of residue inputs under MT
treatments enhanced the actinomycetes population by 34.6% and 25.3% over the initial
status (12.56 & 10.77 × 106cfu g-1) in the layers of 0-5 cm and 5-10 cm, respectively.
Soils of these two layers under MT treatments also registered significantly higher
population of actinomycetes (19.6 % and 17.4 %) over CT treatments. Growing of
follow-up cover crops enhanced the actinomycetes population in the tune of 12.2 % and
8.3 % over the NCC treatments (14.35 and 11.91 × 106cfu g-1) in the top two layers. No
significant difference in the status of actinomycetes population could be observed
among treatments in the bottom layer (10-20 cm).
Table 4.8 Population of actinomycetes (× 106cfu g-1) as influenced by CAPS
0-5cm layer Particulars NCC HG TORIA Mean CT-M 12.36 14.67 14.16 13.73 CT-M+C 13.45 15.13 14.87 14.48 MT-M 15.69 17.24 17.14 16.69 MT-M+C 15.89 17.96 17.59 17.14 Mean 14.35 16.25 15.94 Initial 12.56 M S M within S S within M SEm(±) 0.309 0.318 0.605 0.636 CD (0.05) 1.07 0.93 NS NS
5-10cm layer Particulars NCC HG TORIA Mean CT-M 10.55 11.76 11.49 11.26 CT-M+C 11.16 12.24 12.06 11.82 MT-M 12.75 13.56 13.37 13.23 MT-M+C 13.18 14.26 14.11 13.85 Mean 11.91 12.95 12.76 Initial 10.77 M S M within S S within M SEm(±) 0.544 0.212 0.645 0.424 CD (0.05) 1.882 0.619 NS NS
exáâÄàá
61
10-20cm layer Particulars NCC HG TORIA Mean CT-M 9.34 9.66 9.49 9.50 CT-M+C 9.77 10.16 9.96 9.96 MT-M 9.66 10.47 10.33 10.15 MT-M+C 10.22 10.78 10.59 10.53 Mean 9.75 10.27 10.10 Initial 9.43 M S M within S S within M SEm(±) 0.348 0.243 0.528 0.486 CD (0.05) NS NS NS NS
Fig.4.8 Population of actinomycetes (× 106cfu g-1) as influenced by different CAPS
8
10
12
14
16
18
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
12.56
b
b
aa
b
aa
Act
ino
my
cete
s p
op
ula
tio
n (
×1
04
cfu
g-1
)
Treatments
0-5 cm
6
7
8
9
10
11
12
13
14
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
10.77b
b
a
a
b
a a
Act
ino
my
cete
s p
op
ula
tio
n (
×1
04
cfu
g-1
)
Treatments
5-10 cm
exáâÄàá
62
4.3.2 Microbial Biomass Carbon (MBC)
The microbial biomass carbon (MBC) increases much more readily due to
changes in tillage system or residue supply and the increase is more conspicuous in the
tope few centimeters due to concentrated C input near the soil surface. The soil MBC of
different treatments across the soil depths were presented in Table 4.9, and
Fig.4.9.Establishment of MT systems significantly enhanced the MBC of soils by
115.1% and 66.5% over the initial status of 82.3 and 78.6 µg C g-1 in the layers of 0-5
cm and 5-10 cm, respectively and the corresponding increase over CT treatments were
88.1% and 49.9%. Accumulation of crop residues through cover crops elevated the
MBC of soils by 21.5% and 14.3% as compared to NCC treatments (118.5 and 99.6 µg
C g-1) in the top two layers (0-5 and 5-10cm). The MBC of soils under different
treatments increased from surface to downwards and at 10-20 cm layer, no significant
variations could be observed.
Table 4.9 Impact of CAPS on soil MBC (µg C g-1)
0-5cm layer
Particulars NCC HG TORIA Mean
CT-M 74.53 96.77 89.47 86.92
CT-M+C 93.23 108.67 101.80 101.23
MT-M 146.07 177.40 163.37 162.28
MT-M+C 160.10 219.17 195.70 191.66
Mean 118.48 150.50 137.58
Initial 82.3
M S M within S S within M
SEm(±) 3.175 3.195 6.107 6.389
CD (0.05) 10.98 9.32 NS NS
exáâÄàá
63
5-10cm layer Particulars NCC HG TORIA Mean CT-M 75.57 88.47 86.13 83.39 CT-M+C 87.70 94.10 91.83 91.21 MT-M 112.43 134.37 127.77 124.86 MT-M+C 122.57 147.37 140.63 136.86 Mean 99.57 116.08 111.59 Initial 78.6 M S M within S S within M SEm(±) 3.086 1.522 3.963 3.043 CD (0.05) 10.68 4.44 NS NS
10-20cm layer
Particulars NCC HG TORIA Mean
CT-M 76.4 79.4 78.3 78.0 CT-M+C 79.3 82.2 81.1 80.9 MT-M 70.3 73.2 74.1 72.5 MT-M+C 72.1 79.7 77.7 76.5 Mean 74.5 78.6 77.8 Initial 74.7 M S M within S S within M SEm(±) 1.976 1.254 2.846 2.508 CD (0.05) NS NS NS NS
4.3.3 Microbial Quotient
The microbial quotient is the ratio of MBC to SOC expressed as ratio or
percentage and it is very often used as a measure of C availability to micro-organisms.
The microbial quotients from the soils of different layers were presented in Table 4.10,
and Fig.4.10. In the surface layer (0-5 cm), the microbial quotient of MT treatments
were higher (2.03%) than CT treatments (1.53%) and that of cover crop treatments
(1.83%) were more than NCC treatments (1.68%). Similar trend was also observed in
the layer of 5-10 cm. But the microbial quotient of the soils of the bottom layer (10-20
cm) exhibited a reverse trend with the higher values in CT treatments (1.68%) as
compared to MT treatments (1.51%). There was very little variation in the values of
microbial quotient between cover crops and NCC treatments in the bottom layer.
exáâÄàá
64
Fig.4.9 Microbial Biomass Carbon (µg of C g-1) as affected by CAPS.Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05
0
50
100
150
200
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
82.3 dc
b
a
c
ab
MB
C (
µg
C g
-1)
Treatments
0-5 cm
0
20
40
60
80
100
120
140
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
78.6c
c
ba
c
a b
MB
C (
µg
C g
-1)
Treatments
5-10 cm
68
70
72
74
76
78
80
82
INITIAL CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
74.7
NS
NS
NS
NS
NS
NSNS
MB
C (
µg
C g
-1)
Treatments
10-20 cm
exáâÄàá
65
Table4.10Microbial quotient (MBC/SOC) [%] as influenced by CAPS
Fig.4.10 Microbial quotient across the profile as influenced by CAPS.Treatments with same lower case letter within main plots or sub-plots were not significant at P = 0.05.
4.4 Maizeequivalent yield (MEY)
Significant variations in maizeequivalentyield(MEY) among tillage and
cropping systems were observed at the end of 3rd cropping year (Table 4.11 andFig.
4.11). Even though the maximum MEY was obtained from MT with
1.40
1.50
1.60
1.70
1.80
1.90
2.00
2.10
2.20
CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
M-q
uo
tie
nt
(MB
C/S
OC
) [
%]
Treatments
0-5 cm 5-10 cm 10-20 cm
Treatments 0-5cm 5-10cm 10-20cm
Main plot
CT-M 1.50 1.60 1.67
CT-M+C 1.55 1.62 1.68
MT-M 1.95 1.76 1.50
MT-M+C 2.10 1.77 1.51
Sub-plot
NCC 1.69 1.64 1.57
HG 1.84 1.72 1.60
TORIA 1.81 1.70 1.61
exáâÄàá
66
maize + cowpea intercrop (105.84q ha-1), there was no significant
difference between MT and CT either withsolemaize or with maize + cowpea
intercrop. Inclusion of horsegram (HG) and toria as cover crops in dry season
increased the MEY significantly over fallow (NCC) and the increase was in the tune
of 20.3% and 29.9%, respectively. The maximum MEY of 114.39 q ha-1was produced
from the treatment MT-M+C-TORIA, followed by CT-M+C-TORIA (113.93q ha-1).
Table 4.11EffectofCAPS on MaizeEquivalent Yield(qha-1)
Particulars NCC HG TORIA Mean
CT-M 48.79 67.51 71.66 62.65
CT-M+C 90.75 106.44 113.93 103.70
MT-M 48.60 63.01 70.57 60.73
MT-M+C 97.04 106.08 114.39 105.84
Mean 71.29 85.76 92.64
M S M within S S within M
SEm(±) 1.567 0.970 2.227 1.939
CD(0.05) 5.42 2.83 NS NS
Fig. 4.11 Effect of different CAPS on Maize Equivalent Yield (q ha-1).Treatmentswith same lowercase letter within main plots or sub-plots were not significant at P=0.05
0
20
40
60
80
100
120
CT-M CT-M+C MT-M MT-M+C NCC HG TORIA
b
a
b
a
c
ba
Yie
ld (
q h
a-1
)
Treatments
exá
âÄàá
67
CT 6.15
5.43
4.74
MT 8.72
7.42
4.9
4 5 6 7 8 9 10
0-5.
5-10.
10-20.
SOC (g kg-1)
Depth (cm)
CT 55.1
49.8
42.9
MT 66.9
59.1
46.1
35 40 45 50 55 60 65 70
0-5.
5-10.
10-20.
WSA [> 0.25 mm] (%)
Depth (cm)
CT 18.4
20
22.6
MT 14.8
16.4
20.4
12 17 22 27
0-5.
5-10.
10-20.
WSA(.053-.25mm) [%]
Depth (cm)
Fig. 4.12a Depth wise graph showing the distribution of SOC, WSA under different tillage systems
exá
âÄàá
68
CT 1.53
1.61
1.68
MT 2.02
1.77
1.51
1 1.2 1.4 1.6 1.8 2 2.2
0-5.
5-10.
10-20.
Micrbial Quotient (%)
Depth (cm)
CT 94.1
87.3
79.5
MT 177
130.9
74.5
60 100 140 180
0-5.
5-10.
10-20.
MBC (µg g-1)
Depth (cm)
Fig. 4.2b Depth wise graph showing the distribution of MBC and Microbial Quotient under different ti llage systems
DiscussionDiscussionDiscussionDiscussion
69
DISCUSSION
Sustainable soil management warrants not only proper choice of tillage
techniques, cropping methods, plus ensuring a supply of nutrients; but also
subsequent soil quality evaluations. The beneficial role of Conservation Agriculture
Production System (CAPS) on soil health is well-established world over. Some
promising and interesting results have been obtained from the present study and the
relevant discussion is established below.
5.1 BULK DENSITY
The results indicated an overall reduction of soil BD under MT systems with
cover crops which are restricted to surface layers of 0-5 cm and 5-10 cm. this
remarkable decrease of BD is likely to be a reflection of considerable increase in
SOM content induced by accumulation of litter inputs over the years on the soil
surface, which corroborates the results observed by Fengyan et al., (2011) and
Arvidson (1998). SOM has a direct impact on the BD of soil or inversely on the
porosity, as the particle density of organic matter is considerably than that of the
mineral soil; furthermore, soil organic matter is often associated with increased
aggregation and permanent pore development as a result of soil biological activity
(Jemai et al., 2013). The higher BD in the top layer under CT systems may be
attributed to the loss of finer particles induced by water erosion and low SOM leading
to less aggregation (Lafond et al., 2011). The higher soil BD in 10-20 cm layer
remains unaffected due to low and lack of variations in SOM contents. The significant
negative correlation of SOC with BD with ‘r’ of -0.85** and -0.89** in the layers of0-5
and 5-10 cm, respectively justifies the favourable influence of SOC on soil BD
(Fig. 5.1).
DiscussionDiscussionDiscussionDiscussion
70
Fig.5.1Correlation of SOC with soil BD
5.2 WATER STABLE AGGREGATES
Soil structure is a key indicator in edaphic systems and the ability of the soil to
sustain the biota. Aggregation stability is an indicator of soil structure and is measured
mostly by means of SOC and soil biota. SOC acts as a central nucleus in formation of
soil aggregates, while the biota and their organic products contribute to the
development of soil structure (Sandoval et al., 2008).
The higher proportion of macro-aggregates (>0.25mm) concomitant with
lower proportion of micro-aggregates (0.053-0.25mm) observed in the surface soils
(0-5 cm) and subsoil (5-10 cm) under MT is related to reduced physical impact
y = -0.022x + 1.479
R² = 0.723
1.20
1.24
1.28
1.32
1.36
1.40
1.44
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
BD
(M
g m
-3)
Organic Carbon (g kg-1)
0-5 cm
y = -0.029x + 1.557
R² = 0.787
1.28
1.32
1.36
1.40
1.44
4.00 5.00 6.00 7.00 8.00 9.00 10.00
BD
(M
g m
-3)
Organic Carbon (g kg-1)
5-10 cm
DiscussionDiscussionDiscussionDiscussion
71
leading to lower aggregate turnover rates. Intensive disturbance of the top layer under
CT, in contrast, disrupts macro-aggregates (Six et al., 2000a, Zotarelli et al., 2007).
The higher inputs of fresh organic in MT with cover crops induces increased
microbial activity and production of microbial binding agents leading to the formation
of higher macro-aggregate in the top two soil layers (Mikha and Rice, 2004; Jacoba et
al., 2009). The proportion of soil aggregates in 10-20 cm layer under both MT and CT
is related to the contents of organic matter rather than tillage methods thatcorroborate
the findings of Zhou Hu et al., 2007. The strong positive correlation (r = 0.90** and
0.76** ) of SOC with macro-aggregates in the layers of 0-5 cm and 5-10 cm indicates
the significance of SOC in formation of macro-aggregates (Fig.5.2). The negative
correlation (r = -0.77** and -0.71** ) of SOC with micro-aggregates is related to lower
turnover of macro-aggregates (Fig.5.3).
Fig.5.2 Correlation of SOC with water stable macro-aggregates
y = 4.399x + 28.31
R² = 0.804
30
40
50
60
70
80
90
4 5 6 7 8 9 10 11
WS
A ,
>0
.25
mm
(%
)
Organic Carbon (g kg-1)
0-5 cm
y = 4.139x + 27.88
R² = 0.574
30
40
50
60
70
80
4 5 6 7 8 9 10
WS
A ,
>0
.25
mm
, (%
)
Organic Carbon (g kg-1)
5-10 cm
DiscussionDiscussionDiscussionDiscussion
72
Fig.5.3 Correlation of SOC with water stable micro-aggregates
5.3 Soil Moisture Content
Beneficial effects of crop residues maintenance on the soil surface under
conservation tillage include increased water conservation and soil aggregation
(Hubbard et al., 2013). In the dry period (Rabi season), the amount of water in the
soil reduce gradually irrespective of tillage practices and soil layers as rainfall do not
influence soil water pattern. Tillage reduction in associationwith residue retention
significantly increased the moisture contents in the surface layers mainly due to large
increase in SOC (Kushwaha et al., 2001, Pankhurst et al., 2002, Daraghmeh et al.,
2009). Soil disturbance can also lead to a less stable pore system and pore aggregate
y = -1.445x + 27.37
R² = 0.589
5
10
15
20
25
4 5 6 7 8 9 10 11
WS
A,
0.0
53
-0
.25
mm
(%
)
Organic Carbon (g kg-1)
0-5 cm
y = -1.780x + 29.63
R² = 0.503
5
10
15
20
25
30
4 5 6 7 8 9 10
WS
A,
0.0
53
-0.2
5 m
m (
%)
Organic Carbon (g kg-1)
5-10 cm
DiscussionDiscussionDiscussionDiscussion
73
development that reduce soil moisture contents and regular tillage also enhances
direct evaporation of water from soil surface (Guto et al., 2012). The role of SOC on
soil moisture contents in the surface layers justified by its strong correlation with the
later during sowing (r = 0.82** ) and flowering (r = 0.82** ). Lack of variations in
tillage practices at the deeper layers (5-10 and 10-20 cm) may be related to poor
aggregation and pores because of low SOC contents.
Fig. 5.4 Correlation of SOC with soil moisture content at sowing and flowering at 0-5cm soil depth.
y = 0.685x + 10.46
R² = 0.679
12.00
13.00
14.00
15.00
16.00
17.00
18.00
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
So
il M
ois
ture
Co
nte
nt
(%)
Organic Carbon (g kg-1)
Sowing
y = 0.524x + 7.281
R² = 0.672
8.00
9.00
10.00
11.00
12.00
13.00
14.00
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
So
il M
ois
ture
Co
nte
nt
(%)
Organic Carbon (g kg-1)
Flowering
DiscussionDiscussionDiscussionDiscussion
74
5.4 SOIL REACTION (pH)
The elevation of SOM in the soil surface through residue incorporation
reduced the soil pH in MT systems, which might be related to production of organic
acids as a result of microbial decomposition of organic matter (Logan et al., 1991,
Kern et al., 1993). The acidifying effect on soils under MT due to SOC has also been
reported by Thomas et al., 2007. The significant negative correlation (r = -0.60** )
between SOC and soil pH in the top soils justifies the above findings (Fig.5.5).
Fig. 5.5 Correlation of SOC with pH in 0-5cm soil layer
5.5 SOIL ORGANIC CARBON (SOC)
The combined effect of MT and residue retention or the accumulation of SOC
is greater than the effects of either MT or residue retention alone. In MT, the organic
matter is incorporated faster in the top few centimeters of soil than in CT, where it is
redistributed up to a depth of 20 cm. (Kushwaha et al., 2001)
Considerable buildup of SOC in MT treatments with cover crop in the top two
layers is attributed to greater residue input (5.5 to 6.5 t ha-1of biomass) as well as
lower biological oxidation due to less tillage induced soil inversion (Hel et al.,2009).
Higher SOC contents due to absence of soil redistribution were also observed by
Jemai et al., 2013. Lower physical impacts under MT systems increase aggregate
y = -0.043x + 7.444
R² = 0.365
6.85
6.95
7.05
7.15
7.25
7.35
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
pH
(1
:2.5
)
Organic C (g kg-1)
0-5cm
DiscussionDiscussionDiscussionDiscussion
75
stability resultingin lower aggregate turn over, therefore improved physical protection
of aggregate SOC from decomposition and thus higher SOC stocks. The higher
degradation of macro-aggregate induced by intense soil disturbances in CT system
exposed the formerly incorporated SOC stocks to microbial decomposition (Zotalleri
et al., 2007, Tan et al., 2007) in the top layers. Protection of SOC because of higher
proportion of macro-aggregates under MT systems also corroborates the findings of
Plaza-Bonilla et al., 2013. In the bottom layer (10-20 cm), the effect of surface
accumulated residue on SOC is minimum under MT system whereas in CT system
soil inversion results an even distribution of SOC.
5.6 Microbial Biomass Carbon (MBC)
Microbial Biomass Carbon is considered as a sensitive indicator of soil quality
and is closely related to soil fertility. In contrast to inversion tillage (CT), crop
residues in minimum tillage (MT) are left on or near the soil surface, where they
undergo decomposition. Accumulation of concentrate C input in the top few
centimeters results an increase in MBC near the soil surface and it increases much
more readily due to changes in tillage system or residue supply than SOC (Stockfisch
et al., 1999). The higher MBCin the top layers (0-5 and 5-10cm) of MT than that of
CT corroborates the above findings. Balota et al. (2004) have reported that the fresh
SOM at the surface moderates the soil temperature and moisture that is conducive to
microbial activity and higher MBC.
From the contrasting profiles of MBC observed in MT and CT systems, it may
be deduced that the high SOC near the soil surface is maintained or that the
enrichment will be even continued. In the deeper MT layers (10-20cm), low MBC
values indicate a decline in SOM contents. Similar relations of SOC with MBC in
DiscussionDiscussionDiscussionDiscussion
76
contrasting tillage systems were reported by Doran (1987) and Carter (1991). The
contribution of SOC to MBC is justified by their significant positive correlation (r =
0.98** and 0.99** ) in the layers of 0-5 and 5-10cm (Fig.5.6).
The ratio of MBCto SOC is termed as microbial quotient and is a measure of
C availability to microorganisms. In the top layers of 0-5 and 5-10cm of MT, the
MBC/SOC ratio is much higher suggesting higher substrate availability through the
accumulation of crop residues in the surface soil (Jacobs et al., 2009). On the other
hand, in deeper layers (10-20cm) of MT, the microbial quotient is relatively low
indicating ongoing decline in SOM concentration (Stockfisch et al., 1999) and the
increase of this ratio down the profile in CT may be related to an even distribution of
SOC induced by tillage.
Fig.5.6 Correlationof SOC with MBCofthe soils
y = 31.12x - 95.81
R² = 0.964
40.0
80.0
120.0
160.0
200.0
240.0
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
MB
C (
µg
C g
-1)
Organic Carbon (g kg-1)
0-5 cm
y = 22.54x - 35.05
R² = 0.976
60
80
100
120
140
160
4 5 6 7 8 9
MB
C (
µg
C g
-1)
Organic Carbon (g kg-1)
5-10 cm
DiscussionDiscussionDiscussionDiscussion
77
5.7 Microbial Population
Soil microbial biomass, even though represents only a small proportion of
overall SOM, it is more dynamic than total SOM and a better indicator of how tillage
and cropping systems impact soil health and productivity (Hamelet al., 2006).
Increased soil organic matter content associated with reduced tillage practices
enhanced the population of bacteria, fungi and actinomycetes up to a depth of 0-10cm
under MT, which could be related to availability of higher amounts of substrates for
microorganisms (Mikanova et al., 2009, Sun et al., 2011). Deeper in the soil profiles
(10-20cm), the negligible difference between the tillage treatments is due to lower and
even distribution of SOC in MT and CT, respectively. One explanation for the effect of
MT on microbial biomass is that low-tilled soils provide a more favourable habitat for
microorganisms (Balota et al., 2004). The significant positive correlation of SOC with
population of bacteria (r = 0.91** and 0.77** ) (Fig.5.7), fungi (r = 0.86** and 0.88** )
(Fig.5.8) and actinomycetes (r = 0.87** and 0.86** ) (Fig. 5.9) indicates the favourable
influence of SOC to these microbial community in the top layers (0-5 and 5-10cm).
y = 2.945x + 3.051
R² = 0.821
10.0
15.0
20.0
25.0
30.0
35.0
40.0
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
Ba
cte
ria
po
pu
lati
on
( ×
10
6cf
u g
-1)
Organic Carbon (g kg-1)
0-5 cm
DiscussionDiscussionDiscussionDiscussion
78
Fig. 5.7 Correlation between SOC with bacterial population the soils
Fig. 5.8 Correlation between SOC with fungal population of the soils
y = 2.904x + 3.462
R² = 0.588
10.0
15.0
20.0
25.0
30.0
35.0
4.00 5.00 6.00 7.00 8.00 9.00 10.00
Ba
cte
ria
po
pu
lati
on
( ×
10
6cf
u g
-1)
Organic Carbon (g kg-1)
5-10 cm
y = 1.212x + 5.626
R² = 0.731
8.00
10.00
12.00
14.00
16.00
18.00
20.00
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
Fun
gi
po
pu
lati
on
( ×
10
4cf
u g
-1)
Organic Carbon (g kg-1)
0-5 cm
y = 1.134x + 3.828
R² = 0.774
8
9
10
11
12
13
14
15
4.00 5.00 6.00 7.00 8.00 9.00 10.00
Fun
gi
po
pu
lati
on
( ×
10
4cf
u g
-1)
Organic Carbon (g kg-1)
5-10 cm
DiscussionDiscussionDiscussionDiscussion
79
Fig. 5.9 Correlation of SOC with actinomycetes population of the soils
5.8 Maize Equivalent Yield (MEY)
The MEY in MT systems, though are at par with that of CT system,
marginal increase of MEY in MT may be related to considerable buildup of SOM
that moderates the aggregation, moisture retention, microbial profile and the
dynamics of nutrient mobility at the end of 3rd cropping cycle. The intercrop of
maize and cowpea under both MT and CT systems increased the MEY over sole
maize because of additional gain from cowpea. The elevated MEY due to inclusion
of toria as cover crop is attributed to the higher selling price of mustard.
y = 1.104x + 7.302
R² = 0.748
10.00
12.00
14.00
16.00
18.00
20.00
4.00 5.00 6.00 7.00 8.00 9.00 10.00 11.00
Act
ino
my
cete
s p
op
ula
tio
n (
×1
06
cfu
g-1
)
Organic Carbon (g kg-1)
0-5 cm
y = 1.091x + 5.531
R² = 0.744
8.00
10.00
12.00
14.00
16.00
4.00 5.00 6.00 7.00 8.00 9.00 10.00
Act
ino
my
cete
s p
op
ula
tio
n (
×1
06
cfu
g-
1)
Organic Carbon (g kg-1)
5-10 cm
fâÅÅtÜç tÇw VÉÇvÄâá|ÉÇ
80
SUMMARY AND CONCLUSION
Conservation agriculture production system (CAPS) with the components of
minimum tillage, legume based intercropping and follow up cover crop has been
established at RRTTS, (OUAT) Kendujhar located in the degraded rainfed agro-
ecosystem under North Central Plateau zone of Odisha during 2011, in split plot
design, with an objective to conserve the natural resources and to keep it buffered
against risks. The treatment details are Conventional tillage (CT) and Minimum
tillage (MT) with sole Maize (M) and inter crop Maize + Cowpea (M+C) in main-
plots during wet season and Horsegram (H), Toria (T) and no cover crop (NCC) in
sub-plots during dry season. The impact of CAPS on soil attributes is assessed after
completion of the 3rd cropping cycle in the present study “Soil attributes as influenced
by maize based Conservation Agriculture Production System (CAPS) in a Fluventic
Haplustepts under North Central Plateau zone of Odisha” and the salient findings are
as follows:
� Tillage reduction (MT) lowered the soil BD in the tune of 3.4% and 2.6% over
the initial status (1.32 Mg m-3 and 1.37 Mg m-3) in 0-5 and 5-10cm layers,
respectively, whereas these soils under CT exhibited higher BD (+1.5%,
+2.2%). Cover cropping also reduced the soil BD by 1.3% and 1.0% over
NCC (1.32 Mg m-3 and 1.38 Mg m-3) in the top two layers.
� Higher proportion of macro-aggregates were formed in the surface and
subsurface layers under MT (+14.9%, +11.9%) as compared to CT (-5.3%,
-5.7%). The top soil’s micro-aggregates content on the other hand exhibited a
reverse trend with the higher values in CT (+5.9%, +4.3%) than those of MT
(-14.8%, -14.8%).
fâÅÅtÜç tÇw VÉÇvÄâá|ÉÇ
81
� The MT systems have higher water contents at sowing (16.5%) and flowering
(11.9%) times of dry season cover crops as compared to CT systems (14.7%
and 10.8%).
� The soil pH in the surface layer under MT systems was reduced by 3.7% and
1.5% over the initial status (7.34) and that under CT systems (7.18).
� The SOC contents under MT treatments increases considerably (+27.9% and
15.2%) over the initial status of 6.82 g kg-1 and 6.44 g kg-1 in the top two
layers of 0-5 and 5-10cm, whereas a reduction of SOC (-9.8%, and -15.7%)
were observed in CT treatments for the same layers. Growing of cover crops
also enhanced the SOC of soils by 13.0% and 2.6% over NCC (6.88 and 6.06
g kg-1) in the top two layers.
� An elevation in the population of bacteria (+31.0%, 25.5%), fungi (+22.0%,
+18.6%) and actinomycetes (+19.6%, +17.4%) in the soils under MT systems
over CT systems were observed in the layers of 0-5cm and 5-10cm. the
practice of cover crops also increased the bacterial (+21.8%, +20.1%), fungal
(+15.1%, +13.6%) and actinomycetes (+12.2%, +8.3%) population over NCC
in the top two layers.
� Adoption of MT systems significantly elevated the MBC of soils (+88.1%,
+49.9%) over CT systems in the surface (0-5cm) and subsurface (5-10cm)
layers. Cover cropping also contributed significantly to the MBC pools
(+21.5%, 14.3%) of the corresponding layers.
� The microbial quotient was obtained in systems were in the order MT (2.03%)
> CT (1.53%) and cover crops (1.83%) > NCC (1.69%) in 0-5cm layer,
whereas, the deeper layers (10-20cm), exhibited a reverse trend with higher
values in CT (1.68%) as compared to MT (1.51%).
fâÅÅtÜç tÇw VÉÇvÄâá|ÉÇ
82
� The maize equivalent yield (MEY) did not vary significantly among MT and
CT either with sole maize or with maize+cowpea intercrop. Cover crops of
horsegram and toria increased the MEY by 20.3% and 29.9%, respectively
over NCC. The maximum MEY of 114.39 q ha-1 was produced from the
treatment of MT – M + C – TORIA.
CONCLUSION
Contrasting land management practices resulted in distinctly different effects
on soil condition for the top 0-10 cm depth. The conservation agriculture production
system (CAPS) with the primary principles of minimum tillage, maize – cowpea
intercrop and cover crops of horsegram, alters the depth distribution and concentration
of SOC. The decrease in soil BD, low turnover of macro aggregates, high soil
moisture content and elevated MBC, microbial quotient and microbial diversity are
directly related to considerable build-up of SOC induced by surface accumulation of
crop residues promoted by conservation tillage (MT) management. Rapid depletion of
formerly incorporated SOC through biological oxidation because of continuous
exposure and redistribution of soils across the profile in CT systems imports an
adverse effect on overall soil quality. The trends in soil organic matter related
properties in the present study, indicates continuous cropping in minimum tillage are
creating a more favourable plant growth environment relative to crop sequence with
fallow in conventional tillage can be an adoptable intervention to sustain yields and
soil health in the degraded rainfed agro-ecosystems under North Central Plateau zone
of Odisha. However, information on aggregate size carbon will reflect the true
dynamics of carbon sequestration in conservation agriculture production systems.
U|uÄ|ÉzÜtÑ{ç
i
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