Introduction to Soil Microbiology: Complete Lecture & Notes

[00:00:01][Music] asalam alikum my students welcome to my YouTube channel this is a lecture series of soil microbiology this lecture series consists of basic lecture points for the beginners of microbiology students I wish this lecture series will highly be fruitful for the students this is the first lecture of soil microbiology in which we will study about introduction to soil microbiology so what is soil microbiology how can we Define soil microbiology it's very simple if we know about the microbiology means study about the microorganisms so soil microbiology just shows the study of microorganisms particularly present in soil and their major role and different fun functions in soil what are the microorganisms microorganisms are divided in different groups such as bacteria fungi algae protozoa and viruses soil how can we explain the term soil soil can be defined as the uppermost loose surface of the Earth crust from which plants Drive their water and nutrition for their survival and get mechanical support soil can defined in many ways for example the region of the Earth where biology and geology made this region is also can be called as soil rolate what is the term regate in engineering soil is called as regolit means a layer of loose heterogenous material covering Solid Rock soil profile always there are two terms are commonly used in soil microbiology soil profile and soil horizontal so let first we Define the soil profile what is a soil profile soil profile indicates the vertical section of the earth up to 2 amm if we look at the arrow that clearly indicates the vertical section of the earth so this vertical section shows the soil profile now soil horizone what is soil horizone soil profile when horizontally cut into different sections so the each section will be called as a horizon types of Horizons soil horizons can be classified into different types such as Horizon a horizon B Horizon C and Horizon D Horizon a can further be classified into Horizon A1 A2 but this is the introductory clause so just we have discussed the major types of the soil horizon such as a b c and d characteristics of horizon a soil horizon a also called as top soil this is the first layer of the soil darkest layer of soil dark brown are black in color biological activities are at higher red high concentration of organic and inorganic matter presence of living organisms plant roots and in soil horizone B also called as sub soil this is the second layer of soil lighter in color fine particles and minerals are present low concentration of organic and inorganic matter is compared to Horizon a little number of microorganisms are found Horizon C also call as parent material it is a third layer of soil lightest in color no nutrients animals or plant growth we mineral materials are found partially broken down in organic material soil horizon D which consist of of B rocks it is the last layer of the soil it has not been weathered or broken down yet means these are the B rocks parent material no nutrients animals or plant growth found unweathered rocks are found no l exist difference in soil horizont soil horizon can be differentiated based on thickness chemical constitutents means organic and in organic material Iration color texture and water [Music] relation this is is the second lecture of soil microbiology lecture Series in this lecture we will discuss about the composition of soil so what is the composition of the soil what are the different components of soil a typical soil is composed of five different component such as minerals organic matter water air and living population now minerals minerals are the largest component of a typical soil and consist of 45% of the total soil volume minerals include aluminium iron calcium magnesium sodium phosphorus and silicon dioxide organic matter organic matter is the basic component of a soil and consist of approximately 4 to 5% of the total soil volume organic matter mostly found in the form of humus water water is found beneath soil particles water can make approximately 25% of the soil volume water is very essential for transporting nutrients and highly important for biological and chemical decompostion process air air consist of approximately 25% of the total soil volume air carries different gases in soil such as carbon dioxide oxygen and nitrogen oxygen is needed for microbial respiration carbon dioxide is essential for plant functions and nitrogen is important for nitrogen fixing bacteria in soil living population living population in soil consist of different living organisms such as Earth forms nematodes and large numbers of microorganisms including bacteria eoms and fungi living population makes up only 1% of the total soil volume among the living population microorganisms are very essential for the decompos comption of organic matter in soil minerals in different soils the most common minerals found in soil are iron potassium magnesium calcium and sulfur however some major minerals found in some soils of USA are chenite Mon moride and Elite soil particles and their size such as K it consist of 0.2 mm in size selit 0.2 to 0.02 mm fine s 0.02 to 0.2 mm Co s 0.2 to 2 mm fine gravel 2 mm soil less than 40% clay may be classified as sandy soil physical characteristics of soil number one texture means appearance or consistency of soil the combination of mineral fractions and organic matter fraction give soil its appearance or consistency number two color soil color can show the concentration of different organic matter the parent material and weathering of the soil the red color soils are due to the presence of iron phosphorus black color soils are due to the high concentration of organic matter in the form of humus some soils are in dark brown color due to the rich in different organic matter some soils are in yellow color and this yellow color is due to moist conditions and less weathering including restrictive drainage number three soil depth soil depth or thickness is a critical attribute of any soil the depth determines rooting moisture and nutrient storage depth of soil differs greatly for different soil types number four soil structure single particles when assembled appear as larger particles and these are called as Aggregates the aggregation of soil particles can occur in different patterns resulting in different soil structures soil structure is assembling of individual particle of sand slip and Clay number five porosity space between the particles Poe spaces facilitate the avail ility and movement of air are water within the soil environment soil porosity is the gap between solid particles which contains water and [Music] air this is the third lecture of soil microbiology lecture Series in which we will discuss about soil formation so what is soil formation soil formation also called as pedogenesis is a process of transformation a breaking down of bed rocks means parent material due to physical and chemical changes simply soil formation is a soil Genesis occurs due to weathering of rocks soil formation occurs due to some specific factors these factors vary worldwide and creating very soil combinations soil forming factors there are five major soil forming factors such as parent material weathering organisms topography and finally time parent material parent material for soil formation indicates bed drops organic material or old soil surface are deposit from water wind glaciers and volcanoes or even material moving down a slope which also will be considered as a parent material bedrocks are converted into sediments by weathering and finally into soil by other factors climate or weathering the weathering consist of heat rain snow Sunshine wind and other environmental factors organisms organisms are the major factors in soil formation the living organisms consist of plants and animals including microorganisms among the living organisms microorganisms play a major role in soil formation the microorganisms decompose and convert the remains of dead PLS and animals into organic matter that organic matter is very essential for soil formation now topography Topography is a soil forming factor which indicates location of a soil on landscape indicates how the climatic process impacts like as soils at the bottom of a hill get more water than the soils on the slopes mineral accumulations plant nutrients type of vegetation erosion and water drainage are dependent on the topography now time all the soil formation factors depend upon time soil for is not an easy process it takes hundreds or thousands of years differences in soil forming factors finally the differences in soil forming factors from one location to another influence the process of soil [Music] formation this is the fourth lecture of soil microbiology in this this lecture we will discuss about soil tonomy so what is the tonomy tonomy is the study of classification based on distinct properties and characteristics so soil tonomy particularly shows the study of soil classification system soil tonomy system was developed by United States Department of Agriculture and National Cooperative soil survey there are certain terms or units used in soil classification system such as Pon it is a 3dimensional sample of a soil characterized with all its horizont Pon is the fundamental unit of soil classification system in other term polyon a group of closely associated pedons in the field soil series a group of soils with similar profiles developed from same parent materials is called as soil series soil classification system is compared to classification system of living organisms such as Kingdom phm class order family genus and species soil classification system consist of order suborder General group subgroup family and series soil orders soil has been classified into 12 different orders based based on the distinct properties such as specific Horizons moisture and temperature contents color texture and structure of soil and also based on concentration of organic matter clay iron aluminum oxides and soil dep moreover all soil orders end with so the order names are as anti Sol inceptisol gelisol Hol andisol arisol vertisol mol ultisol alisol spodosol and oxisol antisol soils antisol soils have no welldeveloped profile no different Horizons however consist of only of horizon a inceptisol soils the term inceptum a Latin language means beginning so these are new developed soils more developed than antols however like some features is compared to the other orders jellis so soils the term jellis so right from Latin word gilar to freeze these are the soils of very cold climate dark blackish color due to accumulation of organic matter characterized with Horizon a and Horizon B hoso soils Greek hiso means tissue these type of the soils are rich in organic matter formed under water loded areas and they are characterized with layered organic matter andisol soils from Japanese Ando means black soil these are volcanic soils dried from volcanic Edge very fertile soils containing high concentration of glass and amorphous coloidal materials including alopen and fery hydde a so Latin arid means dry these are called as desert soils found in dry climate are water deficient areas with low organic matter and accumulation of lime sodium and other salts what is Soul soils Latin V means turn turning these are clear Rich soils which shrink and swell with turning into moisture content dark and black in color and are very high fertile soils consist of horizon a but no Horizon B found mol soils Latin molish means soft these are cross land soils with high concentration of organic matter and high fertility semiarid to semihumid soils characterized with Horizon a ultisol Latin ultimate means lost these are red clay soils with high concentration of clay particles rich in nutrients such as iron calcium and potassium and are acidic in nature suitable for for forestry in Indonesia ultisol soils are used for Palm o cultivation and these are very potential for Horticulture crops alisol alisol soils means indicates the aluminium and iron these are Forest soils formed under Forest areas high fertility with semiarid to human soils m L acidic in nature espoo soils Greek espod means wood Edge these are acidic soils accumulation of humus aluminum and Ferris oxide they are cool wet and Sandy soils found in Forest oxisol French oxide shows the oxide particles highly weathered soils red yellow in color due to accumulation of high concentration of iron Ferris aluminium oxides and hydroxides found in tropical and subtropical [Music] areas asalam Alum my students welcome to soil microbiology lecture Series in this lecture we will discuss about soil microbes particularly soil bacteria soils are the excellent culture media for the growth of many kinds of microorganisms one spoonful soil contains 1 million or even several billions of microorganisms most of the soil microorganisms found in the surface layers of about 6 to 12 in of the soil and the number of micro organism decreases in depth the number and kind of microorganisms found in soil dependent upon the nature of the soil and the concentration of organic matter temperature moisture death and season of the year General functions of soil microorganisms soil microbes play an important role in soil such as decomposition nitrification nitrogen fixation and denitrification and even many more other functions mainly the decomposition of various kinds of organic matter and plant and animal material is one of the major role played by soil microorganisms for the transmission of chemical substances that can be utilized by other organisms soil microorganisms serve as the biochemical agents for the conversion of complex organic compounds into simple inorganic compounds types of microbes in soil several types of living organisms are found in soil however there are five major groups of microbes found commonly in soil such as bacteria acomi seeds fungi Al and protozoa soil bacteria bacteria are the smallest and Free Living population in soil bacteria are considered as the most important soil microorganisms due to their size and simple morphology groups of bacteria found in soil vogi in 1925 classified soil bacteria into two broad groups such as autus and alas autus soil bacteria are known as the true residents in soil these are long survival and help in biological functions these type of the bacteria Drive their nutrients from from organic fraction of the soil but no any external source of energy whereas electus bacteria they are called as zymogen are fermentation producing bacteria even they are also called as Invaders they are less in quantity is compared to autus substrate is need needed to perform chemical transformation they require external source of nutrients for energy the population or growth increased after addition of organic material in soil and with exhaustion of organic nutrients their growth decreased rapidly morphological types of bacteria mostly found in soil such as coai basil and espira the bacteria with Coy morphology are not in common in soil whereas the basil are found as most numerous due to endospore formation while Spa are found in very small number in soil types of soil bacteria based on function in soil soil bacteria play an important role in soil these bacteria produce different types of the extra cellular enzymes such as amyas proteas lipas phosphates and even many more other extracellular enzymes also soil backra produce antimicrobial substances So based on different functions these type of the bacteria are classified into several groups such as decomposers which play an important role in decomposition of organic matter nitrogen fixers these bacteria extract nitrogen gas from air and convert it into different forms used by plants among the nitrogen fixers the nitrobacter species are known know as the nitrogen fixers and other group called as disease suppressors this type of the soil bacteria release antibiotic substances to suppress the growth of other bacteria or particular competitors actinobacteria actinobacteria slowly break down humic acids in soil this type of the bacteria prefer non- acid soils with more than 5 pH sulfur oxidizers these bacteria convert sulfides into sulfates used by plants the examples of sulfur oxidizers are the thiobacillus [Music] bacteria in this lecture we will study about ecology and interactions of microorganisms in soil the the most important you will see some questions related to this topic at the end of this lecture so first what is ecology it is the science that studies interactions between organisms and their environment if we look at the figure here you can see the living organisms with same species and other species they can interact with each other and finally they will interact with their environment so now what is soil ecology soil ecology is the study of interactions among soil microbes and between biotic and abiotic factors in soil environment the microbal ecosystem is the sum of the biotic and abiotic components of soil it includes the total micrell Flora together with the physical compulsion and physical characteristics of the soil the microorganisms that inhabit the soil exhibit many different types of interactions or associations and these interactions of microbes in in soil are divided into different interactions such as neutral interactions positive interactions and negative interactions now let's we talk about the neutral interaction or Association it is the interaction type between microorganisms where two different species of microorganisms occupy the same environment without affecting each other neutral interaction might be transitory as the environmental conditions change such as nutrient deficiency then this relationship may be shifted into other types of the relationships positive interaction or Association this type of interaction is divided into three types such as mutualism also called as symbiosis and other one is commercialism and protocooperation so if we talk about mutualism means it is a symbiotic relation relationship between two organisms in which each organism benefits from relationship sophism or syntropy is one kind of symbiotic relationship in which two different species exchange or transfer of nutrients an example of symm is the association between blue green algae and fungus the association between microa and primary producers is the best example of symbiosis in which primary producer such as plants give organic matter and micro give mineral nutrients now commensalism commensalism is an association or relationship in which one group or species is benefited by while the other is not affected commensalism mostly found in soil with respect to degradation of complex molecules like as cellulose and legine example of this type of relationship found in many soil fungi which can degrade cellulose to glucose this product is utilized by many soil bacteria which are unable to degrade cellulose and only they can utilize fungal breakdown products such as glucose and other organic Assets Now protocooperation protocooperation is a mutually beneficial association between two species but they do not depend on each other for survival an example of protocooperation happens between soil bacteria fungi and the plants that occur growing in soil none of these species rely on the relationship for survival but all of the fungi bacteria and higher plants take part in shaping soil composition and fertility negative interactions negative interactions are divided into four different types such as antagonism competition parasitism and predation now antagonism in this type of interaction or relationship one species is inhibited are adversely affected by an other species in the same environment in this condition several types of microorganisms produce antibiotics or other inhib substances which affect the normal growth of other microorganisms antagonistic relations are the most common in nature an example of antagonism is found between Estus RS and pseudomonas arenosa towards fungi such as esus teras pomos pigments inhibit the germination of Asus spores while styo cus orus produces antifungal agents that are responsible for distortions and highall swellings in asulas fungi now competition since soil is full of various types of microorganisms this is the reason these microorganism exhibit competition among themselves for space and nutrients in this situation the dominant microorganisms will eliminate the others for example exogenous nutrients are required for the germination of climate spores of fungi particularly fusium fungi in soil but some of the other fungi and bacteria eat up or diminish these essential nutrients required for Spore germination in this way they hinder Spore germination of fusium fungi and resulting decrease in population of fusium fungi in soil moreover some soil bacteria compete for space and suppress the growth of fungi in soil an example of computation for Limited nutrient is inter specific computation and intra specific computation if you look at the figure you can see both inter specific and intrap specific competition first the species one will compete with species two and this is called as the inter specific computation but when the nutrients will be more limited then these species are the members of the same species will compete with each other and this is the intra specific competition now parasitism parasitism is the non-mutual relationship between two organisms in which one organism lives in or on and other organism and may also harm that one parasites can be classified as ectoparasites and endoparasites based on attachment with host the parasite is dependent upon the host and feeds on the cells tissues or fluids of the host organism several types of parasites consisting of fungi protozoa and neemors are found in soil predation it is an association in which Predator organism directly feed and kills the pre organism Predators may or may not kill their prey prior to feeding on them but predation always results in death of its prey and the absorption of the praise tissue through conception several species of soil inhabitant mob bacteria also called as slime bacteria are known as predators of other microbes an example of myxobacterial species such as mocus zenas exhibit different characteristics including Fring body for formation and Spore formation with morality and group predation on both bacteria and fungi mob bacteria use gliding morality to search the soil Matrix for prey and produce a wide range of antibiotics and lighting compounds that kill and decompose prey cells moreover some fungi such as neatus fungi are the best predatory soil fungi the term Nagi means eating of nematodes by fungi nematophagous fungi are also obligate parasites of nematodes however majority of these fungi are facultative seides nematophagous funi are used for biological control of plant parasitic nematodes and these type of the fungi are also called as carnivorus fungi because they trap and diges the neats there are several species of the nemat fungi the most common species is the pomis species which are considered as the best Neato FAS funi [Music] lecture Series in this lecture we will study about organic matter and its decomposition in soil why microorganisms decompose organic matter and why do we care about the decompostion moreover some questions related to this topic are given at the end of the lecture sources of organic material in soil so what are the different sources of organic matter in soil organic matter in soil comes from several sources such as from Plants animal tissues excretory products all of these substances are materials sooner or later are subjected to microbal attack and finally converted into food of the soil organisms major forms of organic matter organic matter is divided into three major forms such as L dtis and humor so let's first discuss about the litter litter is one of the organic matter forms which shows dead plant material such as leaves bar Twigs that have been Fallen to the ground lit also shows the waste products that have been disposed improperly now de writers it shows particularly de particulate organic matter bodies are fragments of dead organisms as well as FAL deas means the vest or debris of any kind of organic matter now humus humus is a uniform and dark colored ous mass of organic matter it is an organic component of soil formed by the complete decompostion of leaves and other materials by the soil microorganisms hum serves as the source of energy essential plant nutrients there are at least 16 Essential Elements for plant growth plants must have these types of nutrients to perform various physiological functions these nutrients consist of primary nutrients which are also known as macro nutrients primary nutrients are usually required in large amounts and include carbon nitrogen hydrogen oxygen phosphorus and potassium now secondary nutrient n these type of nutrients usually required in moderate amounts compared to the primary essential nutrients the secondary nutrients are calcium magnesium and sulfur some nutrients are called as micronutrients are tress nutrients these nutrients are required in very low amounts in plant as compared to the primary or secondary nutrients micronutrients or copper iron manganes mum and zinc organic constituents of plants according to Alexander in 1961 the organic constituents of plants are classified into six br broad categories such as cellulose the most abundant chemical constitute hemicellulose ligin water soluble fractions ether and alcohol soluble fractions and proteins now decomposition of organic material in soil so what is decomposition decompostion is a biological process that includes the physical breakdown and biochemical transformation of complex organic molecules of dead material into simpler organic and inorganic molecules simply the decomposition means breakdown of dead plant and animal material resulting in release of nutrients there are five different states of decomposition such as fragmentation in which organic matter is break down into little pieces by the decomposers followed by leeching catabolism humidification and finally mineralization why microorganisms decompose organ matter microorganisms decompose organic matter for the purpose of supplying energy for the growth supplying carbon for new cell synthesis since sales of most of the microorganisms commonly contain approximately 50% of carbon that is Drive mainly from the organic substances but why we care about the decomposition decomposition is highly important in releasing nutrients tied up in dead organic matter and R it B to the soil decompostion process to understand decompostion process we can see this figure for an example this is a tree growing in soil now this is a green leaf falling to the ground now some of these day trees are eaten by insects including other animals means nutrients and energy inter food web some of these nutrients Lee into soil by chemical action and results in organic rich soil moreover these leaves are dead organic matter partially consumed by decomposers such as fungi and bacteria and become in the form of litter so further decomposition by earth worms bacteria and fungi and other organisms found in soil and finally converted into humus in soil so this organic rich soil again benefit beneficial for the plants decomposition process the decomposing process is divided into three main processes such as assimilation means the conversion of substrate materials into protoplasm mic materials for example organic carbon to microbal carbon or protein into micrel protein number two mineralization means conversion of organic substance to inorganic form for example protein from the organic matter will be converted into inorganic nitrogen in soil number third immobilization immobilization means the conversion of inorganic form into organic form such as inorganic nitrogen from soil converted into the micrel protein decompostion of cellulose cellulose is an abundant organic compound on Earth it is a carbohydrate composed of the glucose units linked with beta 14 linkage of the sugar molecules cellulose chemical formula consist of C6 h105 and it is formed in cell wall of the plants and present in the form of submicroscopic Rod shaped units known as Mells a group of meiles is known as microfibrils several other poly saturies such as xylin Menon arabos and Galatin are associated with the cellulose cellules is the enzymes that degrade the cellulose the decomposition of the cellulose is carried out by aerobic anerobic and micro alop bacteria filamentous fungi bidom my seeds thermophilic fungi acoms and certain protozoa now decompostion of hemicellulose hemicellulose is also the major component of the plants next to cellulose these are water insoluble polyat and on hydrolysis yield hexoses pentoses and uronic acids so the based on presence or absence of uranic acids this organic matter is divided into two types such as polyuronide hemicelluloses having uronic acids and celluloses no uranic acids many fungi bacteria and eomes are involved in decomposition of hemicelluloses hemicellulose is the enzyme that hydroly the hemicellulose polyat now decomposition of lignin lignin is the third major component of the plant tissue the amount of ligin is high in Woody material approximately 15 to to 35% 3 to 6% of the lignin is found in secondary layers of the cell wall and in the middle lamula ligant is always associated with the other polysacharides and never occurs in Free State the decomposition of liin is carried out by the members of higher fungi such as pdoms and few esoms the role of bacteria in ligin decomposition is not very clear but bacteria may play role after the participation of fungi Lig or lignin peroxides is the enzyme that hydroly the ligin decomposition of starch starch is a white granular organic component of the plants in photosynthetic plants Storch is accumulated in leaves in other plants it is tied in tuber bulbs underground romes fruits and seeds also the large quantity of starch is found in xylm flim or cortex and pit regions of the plants a Storch is composed of two main components such as Amo and amop pactin amyes is the enzyme which degrades or breaks down the starch the decomposition of starch is carried out by almost all of the major soil microorganisms such as achromobacter species basus species chromobacterium Clum species nocardia strepto misis asilas fusium ropas and few flous fungi decomposition of kytin kytin is a basic unit of amino sugars and it is composed of lung CH of of an atile glucose amine units the sources of origin of kittin in soil are mostly insects and fungi that live in soil the Cil walls of Bido myates and yeast are usually rich in kiteen also found in skeleton of many invertebrate animal kitinas or chobas are the enzymes which are used to degrade the kiten substances among the microorganisms Acom acides play a major role in decomposition of kytin substances bacteria and fungi usually play a little role in degradation of kiten substances now questions related to this topic number one what is the difference between lit dtis and humus what do you mean by TR elements names of water soluble components in Plants why microorganisms decompose organic matter why is decompostion of organic matter is so important what are the different stepes of decomposition of organic matter what do you mean by immobilization what is difference between polyuronide hem Solosis and celluloses which one of the organic compounds in Plants always found in associated with other polyes and never occurs in free state which type of organisms play a major role in decompos of kytin [Music] substances Series in today's lecture we will will talk about very interesting topic pesticides their use and also we'll discuss about the adverse effects of pesticides on human responsible for cancer and other serious issues moreover in the end of this lecture you will see some important questions regarding this topic so what is a pesticide a chemical used to kill paste is generally known as pesticide so what is a paste paste just shows insect or other animals plant pathogens and weeds that attack crops food and livestock pesticides are used especially in agriculture crops some pesticides are harmful to humans either from direct contact or as a residue on food types of pesticides there are different types of pesticides such as insecticides fungicides herbicides rodenticides mides and acar sides now what are the insecticides insecticides are those types of pesticides which kill particularly insects and other arthropods fungicides what are the fungicides fungicides are the types of pesticides which kill fungi causing lung diseases some examples of these fungi include pum fuser and rokna species rodenticides rdes are also the types of pesticides which kill particularly Rens rodents include rids mice squarrels nutria and beavers mol SE sides these are the types of pesticides which kill moles moles include octopus esite snails and slugs acar sites acdes are the pesticides which kill particularly ticks and mites ndes nematocytes are the types of pesticides which kill L parasites neemat neemat are the numerous multicellular parasitic worms pneumat are very small and cylinder type worms herbicides now what are the herbicides herbicides are the types of pesticides which kill weeds are these are the chemicals used to kill weed plants what are the weeds and why we want to remove or kill these these type of the plants actually in craw Fields many undesirable weeds a wild plant growing where it is not wanted not desired grow and affect damage the yields of crop so to get rid of such unwanted plant species from the fields different types of herbicides are spread over crop in agriculture effect of herbicides herbicides may have both positive and negative effects Expos of herbicides May esze soil May contaminate water herbicides may affect human health and these May last forever expire of herbicides in aquatic plants indirectly affects on fish herbicides may also kill all desirable organisms examples of different herbicides such as amop PID 24d D chlorophenoxy acetic acid 254t means TR chloro phenoxy acetic acid atrazine glyos foset amop paracord and mcpa two methy for chloro phenoxy acetic acid biodegradation of herbicides herbicides may be degraded by both bacterial and fungal species such as bacilus pseudomonas acromo aspergilus penicillum and lip ises species moreover certain factors such as temperature pH moisture Iration and other nutrient supplies which favor bacterial growth May influence the degradation process 24d D chlorophenoxy acidic acid it is the most widely used herbicide in the world and third most commonly used in the united itates it is an example of synthetic oxen plant hormone many bacterial species are involved to metabolize 24d such as acromo arror cornum flaum and micoplasma species types of pesticides based on chemical aspects chlorinated hydrocarbons carbamates chlorophenoxy acides pids Organo phosphates and many other hetrocyclic compounds among the chlorinated hydrocarbons the best known is DDT Doro dile Tri chloro ethane it is spread worldwide degradation of pesticides degradation of pesticide is a process by which a pesticide is transformed into a substance that is in environmentally adaptable with the site to which it was applied fast degradable agent or fast degradation so what is the fast degradation F degradation means the degradation of the pesticides occur within the 1 to 12 weeks moderate degradation moderate degradation of the pesticides occurs within 1 to to 18 months slow degradation slow degradation means the degradation of the pesticides occurs more than 2 years disadvantages of slow degradation of pesticides slow degradation or non biodegradation May results in accumulation of pesticides in food web and development of resistance among the best organisms moreover accumulation of pesticides in food web May induce highly adverse health problems including cancer and even effects on reproduction immune or nervous system so before use the pesticides must be examined are tested for the possible health effects on humans by the expert team resistance the resistance against the pesticides by a past population may be due to several reasons in addition to slow degradation such as overdose of same pesticides with similar mode of action and also due to Polar and apolar status of a pest and the pesticides chemical structure the use of small amount of pesticides less than lethal do or millions of past organisms may also cause resistance so if you look at the picture one of the past organisms it has a apolar skin so here apolar pesticides are able to penetrate the skin and kill them one more example if you look at this past population there is a significant number of past organisms even in millions so in this case less lethal do may be the re reason of resistance the resistance among the P population is genetically controlled and heritable process pesticide movement and degradation the movement of pesticides is based on two processes such as runoff and leeching whereas degradation of pesticide is divided into several types such as microbal degradation physical degradation such as hydrolysis photolysis and pyrolysis one more degradation type that's the volatilization so among the M run of means movement of pesticide in water generally this occurs in down slope but can also occurs on flat or even slightly uphill ground after floating rain leeching leeching also called as percolation it is a process whereby pesticide move down through soil profile now in degradation the micrell degradation means the breakdown of pesticides by bacteria fungi and other microorganisms so among the physical degradation hydrolysis means the breakdown of pesticides by water photolysis means degradation of pesticides by sunlight and other types of light pyrolysis means the degradation of pesticides by heat or fire factors increasing degradation rate there are certain factors which are involved in Faster degradation of the pesticides such as high temperature involved in Foster degradation higher levels of humidity also involving faster degradation of the pesticides higher number of microbes also cause the faster degradation of the pesticides more slope will cause the more runoff pH effect the pH effect depends on the chemical structure of a pesticide benefits of proper use of pesticides the proper use of pesticides allow agriculture producers to improve the quality quantity and diversity of our food supply use of pesticides in Timber Turf horiculture Aquatic and structural paste control Industries homeowners and home gardeners often use pesticides in their homes yards and on pets to control the P population now some important question regarding this lecture number one give some examples of microbes which play a role in biodegradation of herbicides number two what do you mean by term parol how would you define term pyrolysis what are the effects of slow degradation of pesticides why is degradation of pesticide is necessary what are the benefits of use of pesticides how do past organisms develop resistance against pesticides what is difference between rodenticides and hdes what is the full form of DDT what are acar [Music] sides