ABSTRACT
The effect of pesticides, chchlorodipheny trichloroethane (DDY) and
Benzene hexaxhoride (BHc) on the microflora of the three types of soil
(loamy, clay and sandy soil) was conducted. The serial dietitian
technique was employed up to 10-3 using nutrient agar, potato dextrose
agar and sabourand agar plates. The isolation of both bacterial and
fungal organisms were made before treating the soil types with the two
pesticides), D.D.T and BHC. and after treating the soil types with
D.D.T after treating and BHc. The highest bacterial count before
treating the soil types with D.D.T and BHc was got in loamy soil with
133 per ml having PH 7.1, followed by clay soil with 78 per ml and
least was sandy soil with 42 per ml. while the highest bacterial count
after treating the soil types with D.D.T was gotten in loamy soil 105
per ml, followed by clay soil with 51 and least count was got in sandy
with 28 per ml. Also the highest bacterial count after treatment with
BHc was obtained in loamy soil with 12F per ml, followed by clay soil
with 64 per ml and the least count was got from sand soil with 37 per
ml. The highest bacterial isolate from all the soil types before
treatment with the two pesticides was pseudomonas with 25 per ml,
followed by Bacillus SPP with 24 per ml, and next was achnomycetes
with 19 per ml while the least bacterial organism was Rhizobrium SPP.
The fungal organisms isolates were Aspergillus species, syncophatastrum
species, pernicillum species and mucor species. The results of this
project showed that there was reduction in microflora of the soil types
after treatment separately with the two pesticides. But the effect was
more with D.D.T than with BHc. Also the effects of the two pesticides
was highest in sandy soil followed by clay and lastly the loamy soil.
TABLE OF CONTENT
CHAPTER ONE
Introduction
1.2 Aims and objectives
1.3 Statement of problem
1.4 Hypothesis
1.5 Limitation of the study
CHAPTER TWO
Literature review
2.1 Pesticide labeling and safety
2.2 Various classes and types of pesticides.
2.3 Effects of pesticide on population of invertebrates in soil
2.4 Effects of pesticides on population of vertebrates in the soil
2.5 Effects of pesticides on population of micro organism in the soil
HAPTER THREE
3.0 Materials and methods
3.1 materials
3.2 Methods
3.2.1 Sterilization
3.2.2 Collection of pesticides
3.2.3 Collection of three types of soil loamy clay sandy
3.2.4 Preparation of media
2.2.5 Playing technique
3.2.6 Microbial count, staining and microscopic work
3.2.7 Identification of would
3.2.8 Biochemical test for identification
CHAPTER FOUR
Result
CHAPTER FIVE
Discussions
CHAPTER SIX
6.0 Conclusion and recommendation
6.1 conclusion
6.2 recommendation
References
Appendix
CHAPTER ONE
INTRODUCTION
According to crupta and Daroren (2003) soil is that portion of the
surface of the land which is essential for plant growth. Plant are
anchored in the soil by their root, which spread in all direction and
which by holding on to the soil keep the plant in position plant draw
all their water and most of their food or nutrient from the soil. Soil
is therefore the source of food for plants, animals and man. Soil is of
different types, sandy, clay and loamy soil. Sandy soil has or size
range of 0.2 to 2mm diameter. They are free draining and do not retain
any appreciable amount of soil water. It is brown loose and dry. While
clay soil range in size from 0.002mm and lower and contains more than
40% of clay particles. They are sticky, plastic and easily moldable
into shape. Another type is loamy soil which contains a fair balance of
clay , silt and sand particle and it is the best soil for agriculture,
as it has a high proportion of organic matter or content soil organic
malter represents on accumulation of partially decayed and animal
residues. Such material is continually being broken down as a result of
the work of soil micro –organism consequently. It is a rather
transitory soil constituent and must be renewed constantly by the
additionb of plant residues. The organic matter content of a soil is
small, only 3-5 percent by weight in a representative minerals topsoil.
It is a major soil source of two important mineral elements namely
phosphorous and suefur and essentially the sole source of nitrogen.
Through its effect on the physical condition of soil, organic matter
also increase the amount of water a soil can hold and the proportion of
water available for plant growth. Further more organic matter is the
main source of energy for soil microflora. Without it biochemical
activity would come practically to a stand still soil organic matter
consist of two groups (a) Original tissue and its partially decomposed
equivalent and (b) the humus. The original tissue include the under
composed roots and the tops of higher plants. The materials are subject
to vigorous attack by soil organism and both plant and animal which use
them as sources of energy and tissue building material. The gelatinous,
more resistant products of this decompository both the synthesized by
the micro organisms and those modified from the original plant tissue
are collectively known as HUMUS. This material, usually black or brown
in colour is coloidal in nature. Its capacity to hold water and nutrient
ions greatly exceeds that of clay, its inorganic counterpart. Small
amount of humus thus augment remarkably the soil capacity to promote
plant production.
According to Burges and Raw (1967) loamy like clay is a product of
degradation and synthesis. And the agencies responsible are the living
organisms in the soil both the animal (fauna) and the plant (flora).
These organism engineer a myriad of biochemical changes as decay takes
place. They also physically chum the soil and help stabilize soil
structure. A rast number of organism live in the soil. By far the
greater proportion of these belong to plant life. Yet animal are not to
be minimized especially in the early stage of organic decomposition.
Edward and lofty in 1969 explain that the activities of specific
group of soil organisms are commonly identified by (a) their numbers in
the soil (b) their weight per unit volume or area of soil (biomass) and
(c) their metabolic activity. Although the relative metabolic activities
are not shown, they are generally related to biomass of the organism.
As might be expected, the numbers are highest among the micro organism.
So great are microflora number that they do minate the biomass in spite
of the minute size of each individual organisms. The microflora
monopolize the metabolic activity in soil. It is estimated that 60-80%
of the total soiil metabolism is due to the microflora.
They further said that some of the many naturally and artificially
occuring substance have deleterious effect on the life of at least some
species of organism in the soil by inhibiting the development of these
species. However, there is continuing concern that these chemical
substance may also adversary affect various non parasitic segment of the
soil microflora. These chemical compound substance are called
pesticide. Pesticides are therefore material useful for the control
nutigation of animals detrimental to human or economy. Algaecides,
deforlant and descant herbicides plant growth regulator and fungicide
are used to regulate population of undesirable organisms which compete
with or pristine crop or namental plants. Attractant insecticides,
muticides, accredits, molluscide, nematodes, repellant and rodenticide
are used principally to reduce parasitism and trasmission in domestic
animals, the loss of crop plant, the destruction of processed food
textile wood products as well as parasitism and disease transmission to
human.
Jones (1956) and fletcher (1960) have shown the effect of different
pesticide on type, number and activities. They explain that herbicide
and insecticides can destroy soil micro organism or suppress their
activities if applied at excessive rate. But when applied at recommended
rate these chemicals reach soil concentration of more than 2 or 3 part
per million (PPm) however, some pesticide are obtained from plant and
minerals, while few other are obtained by the mixed culture of micro
organisms insecticides like pyrethin, cruelties and nicotine are
extracted from plant. Also toxin produced by bacillus thuringiesis are
active ingredient against moth and butterfly larrac. The toxins are
sometime called miracle gene”. DDt is an out standing example of
insecticide and probably the most commonly used pesticide. It is known
to contain remarkable properties and does not occur naturally too. Its
first synthesis was recorded in 1874 by a German research chemist
called. Zeidler
In the mid 60s, the benefits steaming from the ability of DDT to
control insect pest could be counter balanced by adverse effects on
other element of the enriroment. Detailed reviews of properties,
stability, prehistoric and impact upon all facets of the environment
were carried out with DDT and other chlorinated organic insecticides.
Concern over the undesirable effects of pesticide culminated
insecticides, fungicide,nd rodenticide act (FIFRA) by public. Law
o2-516, the federal environmental pesticide control act (FEPCA) in
united state of American to prevent unreasonable environmental hazard
from pesticides for general and restricted users as a function of acute
toxicity Benzene hexachloride (BHC) is an organochiloride pesticide for
its efficiency in the control of anthropoid pests. There is fear that
BHc will probable have adverse effect on non targeted microflora of the
soil the aplastic anemia reported in individual said to have been
exposed to BHC has been attributed to benzene, which causes aplastic
anaemia. But BHc is based on cylohexane. Which does not cause anaemia
(grawhill 1982).
1.2 AIM AND OBJECTIVES
i. To determine the effect of pesticide dicblorodipheny
trichloroethane (DDT) and benzene hexachloride (BHC) on the microflora
of three types of soil.
ii. To isolate soil microflora from the three types of soil.
Iii To identify soil microflora of the three type of soil.
iv. To determine the type of soil that is mostly affected by pesticides.
1.3 STATEMENT OF PROBLEM
According to (Higa 1990) Agricultural practices can have a
significant positive and negative impact on soil. For example wrong
application of pesticides (DDT) and BHC) is detrimental to soil
microflora. Therefore it is necessary to determine the effect of D.D.T
and BHC. On the microflora of three types o soil.
1.4 HYPOTHESIS
Ho Pesticides do have detrimental effect on the microflora of three types of
soil.
Ho Pesticide do not have detrimental effect on microflora of the three types
of soil.