study on the effect of soil amendments on persistence of triazole fungicides in soil and its terminal

109 Pages·2015·1.85 MB·English

STUDY ON THE EFFECT OF SOIL AMENDMENTS ON
PERSISTENCE OF TRIAZOLE FUNGICIDES IN SOIL AND ITS
TERMINAL RESIDUES IN TOMATO

A
THESIS
SUBMITTED TO THE
NAVSARI AGRICULTURAL UNIVERSITY
NAVSARI
IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR
THE AWARD OF THE DEGREE
OF
MASTER OF SCIENCE
(AGRICULTURE)
IN
SOIL SCIENCE AND AGRICULTURAL CHEMISTRY

BY
RRAAMMAANNII PPAANNKKAAJJKKUUMMAARR RRAAVVAAJJIIBBHHAAII
B.Sc. (Hons.) Agri.

DEPARTMENT OF SOIL SCIENCE AND AGRICULTURAL
CHEMISTRY
N. M. COLLEGE OF AGRICULTURE
NAVSARI AGRICULTURAL UNIVERSITY
NAVSARI – 396 450

GUJARAT STATE

JULY – 2015

Registration No. - 2010113065
“STUDY ON THE EFFECT OF SOIL AMENDMENTS ON PERSISTENCE
OF TRIAZOLE FUNGICIDES IN SOIL AND ITS TERMINAL RESIDUES IN
TOMATO”

Name of Student : Major Advisor :
Ramani Pankajkumar Ravajibhai Dr. Susheel Singh

DEPARTMENT OF SOILSCIENCE AND AGRICULTURAL CHEMISTRY,
N.M. COLLEGE OF AGRICULTURE,
NAVSARI AGRICULTURAL UNIVERSITY,
NAVSARI- 396 450

A B S T R A C T
The application of organic residues in the form of compost, sludge, effluent
and crop residues to soil is a common agronomic practice followed due to their well-
known benefits for soil fertility. Simultaneously, soil amendments play a vital role in
uncontrolled accumulation and disposal of toxic environmental contaminants such as
pesticides in soil. In estimation, a major chunk of crop produce is lost due to
devastative insect pest and disease incidence. Therefore, pesticides viz. insecticides,
fungicides, weedicides etc are the inseparable component of modern agriculture. Now
a day, use of pesticides has been increased in India which has been reflected from the
increasing number of total registered pesticides. Among crops the consumption of
pesticides is alarmingly higher by fruits and vegetables in India. The use of fungicides
has picked up the pace in recent past in India. Triazole fungicides are commonly used
in tomato which is one of the prominent vegetable crops of India. Of the various
triazole fungicides, hexaconazole ((RS)-2-(2,4-dichlorophenyl)-1-(1H-1,2,4-triazol-1-
yl)hexan-2-ol) propiconazole1- [[2-(2,4-dichlorophenyl)-4-propyl-1,3 dioxolan-2-
yl]methyl]-1H-1,2,4 triazole) and tebuconazole (RS)-1- p-chlorophenyl-4,4-dimethyl-
3-(1H-1,2,4-triazol-1ylmethyl) pentan-3-ol) have been applied to control various
fungal diseases such as powdery mildew, sheath blight, early and late blight of potato,
scab, leaf spot rust, bunt etc. These fungicides have a broad spectrum of activity and
show protective, curative and eradicant action against several actinomycetes and
basidiomycetes classes of fungi. The biochemical mechanism of their fungicidal effect
is by inhibiting the biosynthesis of ergosterol, an essential constituent of cell wall and
Abstract

its absence causes irreparable damage to the cell wall leading to death. As the use of
theses fungicides have been increased, information about pathways of degradation
and factors influencing their degradation is important in predicting the levels of
pesticides likely to remain in soils and allows assessment of the potential risk
associated with the exposure. Therefore, considering these points, an investigation
was carried out at Food Quality Testing Laboratory, N.M. College of Agriculture,
NAU, Navsari during 2014-15 to study the effect of soil amendments on persistence
of triazole fungicides in soil and its terminal residues in tomato with the following
objectives:
 To validate the analytical method applied for residue analysis for the
hexaconazole, propiconazole and tebuconazole from tomato fruits and soil.
 To study the effect of different amendments on the persistence of
hexaconazole, propiconazole and tebuconazole in clay soil.
 To study the terminal residues of hexaconazole, propiconazole and
tebuconazole in tomato fruits and soil.
 To study the triazole (hexaconazole, propiconazole and tebuconazole)
fungicides on microbial growth enzymatic activity in soil.
Prior to initiate the study, the acetonitrile based extraction and dispersive
cleanup approach, widely known as QuEChERS method adopted for the analysis of
residue analysis from amended, non-amended clay soil and tomatoes were validated
based on linearity, accuracy (% recovery), precision (% RSD) and detection limits
(LOD and LOQ).
The linear dynamic range of hexaconazole and propiconazole was 0.05-1.0
mg/kg while that for tebuconazole was 0.25-5.0 mg/kg on GC-ECD and GCMS-ITD,
respectively. The % residual of hexaconazole, propiconazole and tebuconazole was
also calculated and found in the acceptable range i.e. ≥20 %. To established the
accuracy and precision of the analytical method, amended clay soil (amended with
FYM, gypsum, biocompost @ 5 tonnes/ha), unamended clay soil along with tomato
fruits were fortified with hexaconazole, propiconazole and tebuconazole at different
spiking levels. Hexaconazole and propiconazole were fortified @ 0.05, 0.10 and 0.5
mg/kg while tebuconazole was spiked at 0.5 mg/kg level. The recovery of
hexaconazole, propiconazole-I, propiconazole-II and tebuconazole in clay soil
amended with FYM, gypsum and bio-compost was in the range of 74.88 to 99.69 %
Abstract

while that for tomato was 85.62 to 112.98 %. The % RSD obtained from recovery of
hexaconazole, propiconazole and tebuconazole from different matrices were in the
range of 1.56-16.00 %. The LOD and LOQ of analytical method was less than 0.1
mg/kg for all the matrices analyzed. On the basis of method validation studies, it can
be concluded that the analytical method applied for the residue analysis for amended
and unamended clay soil and tomato fruits was accurate (recovery, 70-120 %) ,
precise (RSD; <20 %), sensitive (LOQ> MRL (0.1, 3.0 and 0.7 mg/kg for
hexaconazole, propiconazole and tebuconazole) and instrument‘s response was linear
(% Residual <±20 %).
With a view to study the effect of different amendments viz., FYM, gypsum
and biocompost on the persistence behavior of triazole fungicides i.e. propiconazole,
tebuconazole and hexaconazole in clay soil was carried out along with unamended
control under controlled conditions of laboratory. The clay soil was amended with
above amendments at the rate of 5 tonnes/ha along with a non-amended control soil.
The amended and unamended soils were spiked with triazole fungicides
(hexaconazole, propiconazole and tebuconazole) at the rate of 2 mg/kg. The samples
were drawn on 0 (2hrs after application), 1, 3, 5, 7, 10, 20 and 40 days after the
fortification. The effect of different amendments on the persistence and dissipation
pattern (half-life, regression equation) of hexaconazole, propiconazole and
tebuconazole in clay soil was recorded. Before initiating the study physical and
chemical properties of soil and amendments were determined. The residue of
hexaconazole, propiconazole (I&II) and tebuconazole were built-up in the initial
period (5-7 days) and thereafter gradually started declining. The rate of disappearance
of triazole fungicides was faster in unamended clay soil. The order of persistence (t
1/2,
days) of different triazole fungicides in clay soil amended with different amendments
is as follows;
 Hexaconazole : unamended control (t 20.07 days) < FYM (t 25.08 days)
1/2, 1/2,
< biocompost (t 30.10 days) < gypsum (t 33.44 days)
1/2, 1/2,
 Propiconazole-I : biocompost = unamended control (t , 17.70 days) < FYM
1/2
(t , 20.06 days), < gypsum (t , 20.07 days)
1/2 1/2
 Propiconazole-II : un-amended control (t 18.81 days) < biocompost (t 20.07
1/2, 1/2,
days) < FYM = gypsum (t , 25.08 days)
1/2
Abstract
 Tebuconazole : unamended control (t 16.72 days) < gypsum (t 20.06 days)
1/2, 1/2,
< FYM = biocompost (t 30.10 days)
1/2,

A pot experiment was conducted to quantify the harvest time residues or
terminal residues of hexaconazole, propiconazole and tebuconazole in tomatoes and
also their residues in soil amended with FYM, gypsum and biocompost. The pots
(approx. 10 kg capacity) was filled with unamended soil (control) and clay soil
amended with FYM, gypsum and biocompost at the rate of 5 tonnes/ha. The
experiment was carried with four replications along with an untreated control. After
properly mixing of amendments to the soil, the soil was irrigated. After this, the
tomato seedlings (variety Gujarat Tomato-2, GT 2) procured from Regional
Vegetable Research Station, NAU, Navsari were transplanted in the pots. Two healthy
seedlings were transplanted in each pot at the beginning of experiment. The two foliar
sprays of hexaconazole (5 % S.C. @ 0.05 %), propiconazole (25 % EC @ 0.025 %)
and tebuconazole (25.9 % EC @ 0.035 %) were carried out twice (50 % flowering
and fruiting stage) at 15 days interval. The soil (ca. 50 g/ treatment) and fruit samples
(250 g/treatment) were collected on 3rd day after the last spray.
The results obtained in the study reveals that the maximum terminal residues
in tomato was observed in tebuconazole either grown in amended or unamended clay
soil while minimum were detected in FYM amended soil spiked with propiconazole-I.
The terminal residues of propiconazole (I & II) were less than codex MRL (3.0
mg/kg) while that for tebuconazole and hexaconazole were either on higher side or
equal to their respective MRLs (0.7 and 0.1 mg/kg). However, the harvest time
residues of triazole fungicides varied in the range of 0.54-0.92 mg/kg in clay soil
amended with FYM, gypsum and biocompost. Tebuconazole and propiconazole
recorded the maximum and minimum harvest time or terminal residues in clay soil
either amended with FYM, gypsum and biocompost or unamended, respectively.
The effect of hexaconazole, propiconazole and tebuconazole fungicides were
studied following application @ 2 mg/kg on bacterial count and enzymatic activity in
soil amended with FYM, gypsum and biocompost. The samples were drawn on 0 (2
hrs after the application), 5, 10, 20 and 40 days after the treatment and analyzed for
microbial load (total bacterial count) and phosphatase activity.
The microbial load was higher in triazole fortified clay soil amended with
organic and inorganic amendments with respect to unamended control soil. The total
Abstract

bacterial count was increased in all fungicide treated clay soil (amended and
unamended) with time. The order of total bacterial count recorded in hexaconazole,
propiconazole and tebuconazole treated clay soil is as follow: Biocompost > FYM >
gypsum > unamended control.
FYM, gypsum and biocompost treated clay soil sample have higher
phosphatase activity compared to unamended soil. Phosphatase enzyme concentration
was increased in each soil (amended and unamended) up to 10 days. At the end of the
experiment, the phosphatase concentration in fungicide treated and amended soil was
comparable to untreated control.
Although, the application of organic soil amendments has potential to improve
the microbial load and phosphatase enzyme activity due to increase in easily available
organic carbon content in the soil. This was reflected from the high total bacterial
count and phosphatase enzyme concentration in soil amended with organic
amendments (biocompost and FYM) with respect to inorganic amendment (gypsum)
and unamended control clay soil. But application of amendments had increased the
persistency of triazole fungicides. Biocompost and FYM might have improved the
sorption of triazole fungicides with clay particle which have reflected from the higher
persistency of different triazole fungicides in clay soil amended with organic
amendments. A long duration study may be helpful to get more conclusive results
regarding the effect of soil amendments on persistence of fungicides in soil.
Dr. Susheel Singh
Assistant Professor (Residue Chemistry),
Food Quality Testing Laboratary,
N. M. College of Agriculture,
Navsari Agricultural University,
Navsari - 396 450

CCEERRTTIIFFIICCAATTEE

This is to certify that the thesis entitled “STUDY ON
THE EFFECT OF SOIL AMENDMENTS ON
PERSISTENCE OF TRIAZOLE FUNGICIDES IN SOIL
AND ITS TERMINAL RESIDUES IN TOMATO‖ submitted
by RAMANI PANKAJKUMAR RAVAJIBHAI in partial
fulfillment of the requirement for the award of the degree of
MASTER OF SCIENCE (AGRICULTURE) in the subject of
SOIL SCIENCE AND AGRICULTURAL CHEMISTRY of
the Navsari Agricultural University is a record of bonafide
research work carried out by him under my guidance and
supervision and the thesis has not previously formed the basis
for the award of any degree, diploma or published for other
similar title. All the assistance and help received during the
course of the investigation have been duly acknowledged by
him.

Place: NAVSARI (Susheel Singh)
Date:
Major Advisor
DDEECCLLAARRAATTIIOONN

This is to declare that the whole of the research
work submitted in this thesis for the partial fulfillment of the
requirements for the degree of MASTER OF SCIENCE
(AGRICULTURE) in SOIL SCIENCE AND
AGRICULTURAL CHEMISTRY is the result of
investigation done by the undersigned under the direct
guidance and supervision of Dr. Susheel Singh, Assistant
Professor (Residue Chemistry), Food Quality Testing
Laboratory, N. M. College of Agriculture Navsari Agricultural
University, Navsari and that no part of the work has been
submitted for any other degree so far as a unique research.

Place: Navsari
Date: (P. R. RAMANI)

Countersigned by

(Susheel Singh)
Assistant Professor (Residue Chemistry),
Food Quality Testing Laboratory,
N. M. College of Agriculture,
Navsari Agricultural University, Navsari-396450
ACKNOWLEDGEMENT
After successful completing the long educational
journey, I look back and find that though mine has been a fairly
sail, it has been mesmerizing extravaganza of memorable
experiences. I also realize how difficult it is to wrap my feelings
with plumage of worldly words more so as I am inundated with
emotions. At this gratifying moment completion of my research
problem, I feel obliged to record my gratitude to those who have
helped me.
I express my infinite sense of gratitude to the Goddess
jay gel maa for continuously providing me spiritual energy, which
has inspired me to reach at the highest excellence during my
academic career.
Every author owes a debt to his teachers. Indeed the
words at my command are not adequate to convey the depth of my
feeling and gratitude to my major advisor Dr. Susheel Singh,
Assistant Professor (Residue Chemistry), Food Quality Testing
Laboratory, Navsari Agricultural University, Navsari for his most
valuable and inspiring guidance with his friendly nature, love and
affection, for his attention and magnanimous attitude right from
the first day, constant encouragement, enormous help and
constructive criticism throughout the course of this investigation
and preparation of this manuscript.
The revelation of concealed facts in an investigation
needs a co-operative approach. Hence I acknowledge, with
gratitude and appreciation, the ready assistance involvement and
critical suggestions of the member of my advisory committee, my
co-guide Dr. T. U. PATEL, Assistant Professor, Dept. of
Agronomy, Dr. K. G. Patel, Professor and head Food Quality
Testing Laboratory N.M.C.A. and Dr. H. R. Pandya, professor and
head, Dept. of Agril. Statistics.
I am sincerely thankful to Dr. G.G Patel, I/C Professor
and Head, Dept. of Soil Science, N. M, College of Agriculture,
Navsari Dr. Punit Mehta, Dr. H. M. Patel, Dr. Trupti Vyas. I
gratefully acknowledge the most willing help rendered byDr.
Nitesh Litoriya, VanrajBhai, KeyurBhai, KelvinBhai, Maulik,
Rahul, SwetaDidi, PrachiDidi, AvantikaDidi and other
subordinate staff of FQTL providing help for all the necessary
facilities.
I am also thankful to Dr. M. K. Arwadia (Principal)
for providing me this valuable and golden opportunity to upgrade
my qualification in the Discipline of Soil Science.
Though thanks is taboo in friendship, my conscience do
not permit to refrain myself from expressing my heartfelt feeling
towards to mybeloved, memorable and joyous friends Kanara,
Jashvant, Kamani, Panchal, Paresh, Jeetendra, Pathan, Naresh,
Vivek, Bindu, Jinal, Khyati heartly thankful to my juniors Sagar,
Bhadani, Piyush, Vanpariya, Nakum, Ram, Monika, Nirali,
Siddhi, Sachin, Mamu, Chhotesagar, Kimpal, Chigu, Pethani,
Jaishval, Niral, Divya, Vadaliya, Keyur, Marut, Pensul, Faldu,
Neeta, Rekha and all my juniors and classmate of Soil Science &
Agricultural Chemistry.
I wouldn’t like to forget the incredible co-operation
and inspiration rendered by Mr. Shiroya, Mr. Kaneriya and
Patodiya or the excellent company, love, ever present support,
undying encouragement and constant help during my research
work so my special thanks for them.
It is a time to express my deep sense of gratitude and
heartful thanks to my family members and words run short to
express my indebtedness to beloved parent’s shri Ravajibhai and
Smt. Manjulaben, my sister Daxaben, Harshaben, my brother
Piyushbhai and Truptibhabhi members of my family grand fathers
and grand mothers. I owe my existence, who always wanted for my
success, nourished and inspired me with their love and affections
and for the sacrifice made by them to shape my excellent career.
My special thanks to who always wanted for my
success, nourished and inspired me with her love and affections
and for the sacrifice made by her to shape my excellent career.

Place: Navsari
Date: (P. R. RAMANI)