Microbes in Human Welfare: Class 12 Biology Chapter 8 Hinglish mein

Upjaau garden soil ke sirf ek gram mein das crore se lekar sau crore tak bacteria ho sakte hain, saath mein fungi, protozoa aur viruses bhi. Itne chhote organisms, jinhe tum sirf microscope se study kar sakte ho, microbes (सूक्ष्मजीव) kehlaate hain. Yeh hawa, paani aur soil mein, plants aur animals ke upar aur andar, aur tumhare apne gut mein bhi rehte hain.

Inke rehne ki jagahon ki range kisi bhi plant ya animal se kahin zyada badi hai. Microbes 0 ke kareeb pH wale acidic hot springs mein, Antarctic ice mein, surface se kilometres neeche rock mein aur 100 °C se zyada garam sea-floor vents ke aas-paas bhi mile hain; record holder lagbhag 122 °C par multiply karta hai. Jahan bhi liquid water hai, wahan aksar koi na koi microbe rehne ka tareeka dhoondh hi leta hai.

Microbe shabd mein bahut alag-alag cheezein aati hain (Fig. 8.1). Bacteria, protozoa, yeasts, moulds aur microscopic algae cells se bane hote hain. Viruses kahin zyada chhote hain aur cells hain hi nahi: har virus DNA ya RNA ke around ek protein coat hai, aur woh sirf host cell ke andar hi multiply kar sakta hai. Viroids aur bhi chhote hain, RNA ke nange loops jo plants ko infect karte hain, aur prions galat fold hue proteins hain jo mad cow disease jaisi brain diseases karte hain.

Ek akela bacterium tum nahi dekh sakte, lekin laakhon ek saath dekh sakte ho. Petri dish mein jelly jaise nutrient medium par kuch cells phailao, use garam rakho, aur har cell baar-baar divide hokar ek spot banata hai jise colony kehte hain; yeh ek-do din mein naked eye se dikhne lagti hai. Aisi colonies uga kar hi microbiologists microbes ko identify karte hain, unhe count karte hain aur test karte hain ki unhe kya maarta hai.

Zyadatar logon se microbes ke baare mein poochho to unhe germs yaad aate hain, yaani woh pathogens jo tumne Chapter 7 mein padhe. Lekin pathogens ek chhoti minority hain. Hum food, medicines aur fuel ke liye, saaf paani aur upjaau soil ke liye microbes par depend karte hain, aur neeche ke sections inhe ek-ek karke dekhte hain.

8.1 Household Products mein Microbes

Tumhari kitchen ek chhoti microbiology lab hai. Jab bhi koi raat bhar curd (दही) jamata hai, idli batter ko phoolne ke liye chhodta hai ya bread bake karta hai, to microbes ki ek population yeh kaam kar rahi hoti hai.

Curd jamane ke liye tum kal ke curd ka ek chammach gungune doodh mein milate ho. Woh chammach starter, yaani inoculum hai: usmein arabon lactic acid bacteria (LAB) hote hain, jaise Lactobacillus. Garam rakhne par LAB tezi se multiply karte hain aur doodh ki sugar, lactose, ko ferment karke lactic acid banate hain (Fig. 8.2).

Acid do kaam karta hai. Jab pH lagbhag 6.6 se girkar lagbhag 4.6 tak aata hai, to milk protein casein ke particles apna charge kho dete hain, aapas mein chipak jaate hain aur liquid ko ek soft gel mein phansa lete hain: doodh jam jaata hai. Acid aur bacterial enzymes protein ke kuch hisse ko tod bhi dete hain, isliye curd doodh se zyada aasaani se digest hota hai. Fermentation iski food value bhi badhata hai, khaas taur par vitamin ${\mathrm{B}}_{12}$ ka level badha kar.

Zinda khaaye jaane par LAB tumhare gut ki bhi madad karte hain. Woh intestine ko zyada acidic banate hain aur harmful microbes ko jagah nahi lene dete; yeh ek wajah hai ki curd aur chhaachh probiotic foods mein gine jaate hain.

Idli aur dosa batter bhi isi principle par kaam karta hai. Bhige chawal aur urad dal ka batter raat bhar chhodne par jhaagdaar ho jaata hai aur phool jaata hai, kyunki Leuconostoc jaise bacteria uski sugars ko ferment karke carbon dioxide chhodte hain. Phanse hue bubbles steamed idliyon ko soft aur spongy banate hain, aur acids dosa ko halka khattapan dete hain.

Bread bhi milti-julti wajah se phoolti hai, lekin yahan kaam karne wala ek fungus hai: baker's yeast, Saccharomyces cerevisiae. Dough mein goondhne par yeast cells sugars ko ethanol aur carbon dioxide mein ferment karte hain. Gas dough ko phulaati hai, aur ethanol baking ke time ud jaata hai.

Poore India mein fermentation kai traditional foods aur drinks ko unka khaas swaad deta hai. Kerala, Tamil Nadu aur doosre southern states mein matkon mein ikattha kiya gaya palm sap kuch hi ghanton mein wild yeasts aur bacteria ki wajah se ferment hokar halka alcoholic toddy ban jaata hai. Fish, soybeans aur bamboo shoots ko bhi ferment kiya jaata hai, khaas taur par Northeast mein.

Swiss (Emmental) cheese chhedon se bhara kyun hota hai, jabki Roquefort mein blue dhaariyan hoti hain? Dono cases mein jawab ek microbe hai (Fig. 8.3). Jaise-jaise Swiss cheese ripen hota hai, bacterium Propionibacterium shermanii bahut saara carbon dioxide chhodta hai, aur gas jama hokar bade gol chhed, yaani 'eyes', banati hai.11Tumhari textbook ise sharmanii likhti hai; species ka naam American bacteriologist James M. Sherman ke naam par rakha gaya hai. Roquefort ko mould Penicillium roqueforti se ripen kiya jaata hai, jiski blue-green veins use tez flavour deti hain. Log hazaaron saalon se microbes ki madad se cheese banate aa rahe hain, aur aaj ki saikadon varieties ka texture aur taste kaafi had tak daali gayi species ki wajah se hai.

Iske ulat, paneer microbial food nahi hai. Garam doodh ko nimbu ke ras ya vinegar se phaada jaata hai aur turant dabaya jaata hai, bilkul bhi ripening nahi hoti.

8.2 Industrial Products mein Microbes

Curd ke bowl ko das laakh guna bada kar do, to tumhare paas ek microbial factory hai. Industry chune hue microbes ko tonnes mein ugaati hai taaki beverages, antibiotics, organic acids, enzymes aur medicines ban sakein.

Iske liye jo vessels use hote hain woh fermentors (किण्वक) hain: band tanks, aksar stainless steel ke aur ek ghar se bhi oonche. Andar woh conditions steady rakhi jaati hain jo microbe ko chahiye: temperature, pH, oxygen supply, nutrients aur stirring. Chune hue microbe ko daalne se pehle vessel ko sterilise kiya jaata hai, taaki koi doosra microbe usse compete na kare. Fermentors tumhe Chapter 9 mein phir milenge, bioreactors ke roop mein.

8.2.1 Fermented Beverages

Har alcoholic drink, beer se lekar rum tak, ek hi tarah shuru hoti hai: yeast sugar khaata hai. Log hazaaron saal tak aisi drinks banate rahe, yeh jaanne se bahut pehle ki yeast zinda hota hai. Species Saccharomyces cerevisiae hai, wahi yeast jo bread phulata hai; brewers ise brewer's yeast kehte hain. Iska khaana germinated (malted) grain jaise barley ki sugar ho sakti hai, ya grape juice jaise fruit juice ki sugar, aur iska main product ethanol hai: $\mathrm{C}{\phantom{X}}_6\mathrm{H}{\phantom{X}}_{12}\mathrm{O}{\phantom{X}}_6\stackrel{}{\to }2\mathrm{C}{\phantom{X}}_2\mathrm{H}{\phantom{X}}_5\mathrm{O}\mathrm{H}+2\mathrm{C}\mathrm{O}{\phantom{X}}_2$.

Phir do choices tay karti hain ki kaun si drink banegi (Fig. 8.4): sugar ka source, aur fermented liquid ko distil kiya jaata hai ya nahi. Yeast ethanol ko 15 % se zyada upar nahi le ja paata, kyunki alcohol use hi zeher dene lagta hai, isliye fermentation se seedhe bechi jaane wali drinks kaafi halki rehti hain: wine (grapes se) aur beer (malted barley se). Spirits fermented liquid ko garam karke aur vapour ko condense karke banti hain, jisse ethanol lagbhag 40 % tak concentrate ho jaata hai: whisky grain se, brandy wine ya doosre fruit se, aur rum sugarcane molasses se.

8.2.2 Antibiotics

Antibiotic Greek anti (against) aur bios (life) se bana hai: yeh substances microbes ki life ke against kaam karte hain, sabse zyada un pathogens ke against jo humein infect karte hain. Twentieth century ki bahut kam discoveries ne antibiotics (प्रतिजैविक) se zyada insaani jaanein bachaayi hain.

Penicillin, pehla antibiotic, achaanak mila tha (Fig. 8.5). 1928 mein London ke bacteriologist Alexander Fleming chhutti se laute to unke paas Staphylococcus bacteria ki culture plates ka dher tha. Ek plate par contaminant ki tarah ek mould aa gira tha, aur uske aas-paas bacterial colonies mar gayi thi, jisse ek saaf ring ban gayi thi. Mould Penicillium notatum nikla, aur jo bacteria-maarne wala substance usne jelly mein chhoda, woh penicillin kehlaya.

Fleming patients ka ilaaj karne laayak penicillin purify nahi kar paaye. 1939 aur 1941 ke beech Oxford mein Howard Florey, Ernst Chain aur unki team ne ise purify kiya, dikhaya ki yeh infected mice ko aur phir logon ko theek karta hai, aur mass production shuru karne mein madad ki. World War II ke ant tak yeh hazaaron ghayal soldiers ki jaan bacha raha tha. Fleming, Florey aur Chain ko 1945 ka Nobel Prize in Physiology or Medicine mila.

Penicillin ne raasta dikhaya, to scientists ne aise hi substances ke liye hazaaron soil microbes ko screen kiya. Aaj use hone wale zyadatar antibiotics microbes ke do groups se aate hain: moulds aur, sabse zyada, dhaage jaise soil bacteria jinhe Streptomyces kehte hain (Table 8.3).

Tuberculosis, leprosy (कुष्ठ रोग, kushth rog), plague, diphtheria (गलघोंटू, galghotu), whooping cough (काली खाँसी, kali khansi) aur bacterial pneumonia kabhi bade killers the; ab in sabka ilaaj antibiotics se ho sakta hai. Antibiotics surgery, organ transplants aur cancer treatment ko bhi kahin zyada safe banate hain, kyunki woh un infections ko control karte hain jo warna baad mein hote.

Zyadatar antibiotics kisi aisi cheez par attack karte hain jo bacteria mein hoti hai aur hamare cells mein nahi. Jaise penicillin bacteria ko apni cell walls banane se rokta hai; human cells ki cell wall hoti hi nahi, isliye woh bach jaate hain. Isi wajah se antibiotics viruses ke against bekaar hain, jinki na apni cell wall hoti hai na metabolism: antibiotic se cold ya flu theek nahi hoga.

8.2.3 Chemicals, Enzymes aur doosre Bioactive Molecules

Microbes saste aur tez chemical factories hain. Fermentor mein sugar aur minerals khilaane par har species apne products banati hai, jinhe industry tonnes mein ikattha karti hai (Table 8.4).

Organic acids ek bada group hain. Lactobacillus se lactic acid milta hai, jo foods mein aur ek biodegradable plastic banane mein use hota hai. Bacterium Acetobacter aceti ethanol ko oxidise karke acetic acid banata hai, jo vinegar ka acid hai. Mould Aspergillus niger citric acid banata hai, jo soft drinks, jams aur meethai ko flavour deta hai aur preserve karta hai, aur Clostridium butylicum se flavourings ke liye butyric acid milta hai.22Aaj industry zyadatar iske kareebi rishtedaar Clostridium butyricum ko use karti hai; tumhari textbook C. butylicum ka naam leti hai. Industrial ethanol ke liye ek baar phir main kaam karne wala yeast Saccharomyces cerevisiae hi hai.

Microbes ke enzymes anokhi jagahon par milte hain. Taaza nichoda juice dhundhla hota hai kyunki mehin pulp pectin aur proteins ki wajah se usmein tika rehta hai; juice factories inhe todne ke liye pectinases aur proteases daalti hain, isliye bottled juice saaf dikhta hai. Washing powders mein lipases hote hain, fat todne wale enzymes jo chikne daag dheele karte hain. Hospitals mein Streptococcus bacteria ka streptokinase, jise genetic engineering se behtar banaya gaya hai, 'clot buster' ka kaam karta hai: heart attack (myocardial infarction) ke jaldi baad inject karne par yeh blood ke apne clot ghulaane wale enzyme ko activate karta hai aur blocked coronary artery ko phir khol deta hai.

Do aur microbial molecules roz ki medicines hain. Statins, jaise mould Monascus purpureus ke banaye statins, blood cholesterol kam karte hain.33Tumhari textbook Monascus ko yeast kehti hai; yeh ek filamentous fungus, yaani mould, hai. Statin molecule HMG-CoA reductase ke substrate jaisa dikhta hai, jo cholesterol synthesis ka key enzyme hai, isliye yeh enzyme ki active site ke liye compete karta hai: yeh competitive inhibition ka case hai, jo tumne Class 11 mein padha tha. Fungus Trichoderma polysporum se milne wala Cyclosporin A immune system ko dheema karta hai; organ transplant ke baad yeh body ko naye organ par attack karne se rokta hai.

8.3 Sewage Treatment mein Microbes

Shehar ka har flush, bath aur kitchen sink drains mein paani bhejta hai. Gharon aur shehron ke is mile-jule gande paani ko sewage (वाहित मल) kehte hain. Ismein zyadatar paani hota hai, lekin yeh human excreta, khaane ke tukde, sabun aur microbes ka bahut bada load le jaata hai, jinmein se kaafi pathogens hote hain.

Ise seedhe nadi mein daalne se do tarah ka nuksaan hota hai. Iske pathogens neeche ki taraf rehne wale logon mein cholera, typhoid aur hepatitis A jaisi water-borne diseases phailaate hain. Aur iska organic matter nadi ke bacteria ko khaana deta hai, jo multiply karke paani mein ghuli oxygen khatam kar dete hain, jisse fish aur doosre animals ka dum ghut jaata hai.

Yeh kaam ek sewage treatment plant (STP) mein hota hai, aur kaam karne wale chemicals nahi balki woh microbes hain jo khud sewage ke saath aate hain. Inmein se zyadatar heterotrophs hain, jo organic matter khaate hain; plant ke tanks, pumps aur blowers bas unhe sahi conditions dete hain. Process ka ek physical stage hai aur ek biological stage (Fig. 8.7).

Primary treatment

Primary treatment poori tarah physical hai. Bar screens aur mehin filters ki ek series plastic, chithde aur pattiyon jaisa tairta kachra pakadti hai. Phir paani dheere-dheere ek grit chamber se guzarta hai, jahan ret, silt aur bajri neeche baith jaati hai. Primary settling tank mein aur bhi mehin solids primary sludge ki tarah neeche baithte hain, aur upar ka dhundhla paani, yaani primary effluent, aage badhta hai. Sirf settling se organic load ka lagbhag ek-tihaai hat jaata hai.

Secondary (biological) treatment

Secondary treatment mein microbes kaam sambhaalte hain. Lambe aeration tanks mein blowers primary effluent mein hawa bharte hain jabki paddles use mathte rehte hain. Bharpoor oxygen milne par aerobic bacteria tezi se multiply karte hain aur fungal threads ke saath uljhkar flocs (ऊर्णक) bana lete hain, yaani dheele, jaali jaise gucchhe jo tank ke paani ke jar mein tum dekh sakte ho (Fig. 8.8). Flocs ghule aur tairte organic matter ko khaate hain, aur uske bade hisse ko carbon dioxide, paani aur aur zyada microbial cells mein badal dete hain.

Operators ko kaise pata chalta hai ki paani kaafi saaf ho gaya? Woh uski biochemical oxygen demand (जैव रासायनिक ऑक्सीजन माँग), yaani BOD, naapte hain.

Test mein sample ki ek sealed bottle, bahut ganda ho to dilute karke, andhere mein rakhi jaati hai, aam taur par 20 °C par 5 din, aur uski dissolved oxygen mein giravat naapi jaati hai.44Indian laboratories aksar 27 °C par 3-day test chalaati hain, jo milti-julti values deta hai. Logic simple hai: microbes oxygen tabhi use kar sakte hain jab unke paas oxidise karne ke liye organic matter ho, isliye badi oxygen demand bade organic load ki pol khol deti hai. Isi wajah se high-BOD paani nadi ko nuksaan pahunchata hai: uske bacteria woh oxygen chheen lenge jo fish ko chahiye. Operators effluent ko aeration tanks mein tab tak rakhte hain jab tak uska BOD shuruaati value ka chhota sa hissa na reh jaaye.

Aeration ke baad saaf paani aur flocs ke badhte mass ka mixture bachta hai, aur ek doosra settling tank dono ko alag karta hai. Iske tal mein jama hone wale flocs activated sludge (सक्रियित आपंक) banate hain, jo zinda microbes ka ghana mass hai. Kyunki yeh zinda hai, iska kuch hissa recycle hota hai: aeration tank ke shuru mein wapas pump karne par yeh effluent ke agle batch ko bane-banaaye flocs ke saath shuru karta hai, bilkul waise jaise ek chammach curd taaze doodh ko jamana shuru karta hai. Bacha hua hissa, primary sludge ke saath, bade sealed tanks mein bheja jaata hai jinhe anaerobic sludge digesters kehte hain.

Digester ke andar oxygen nahi hoti, aur microbes ka ek naya set kaam sambhaalta hai: anaerobic bacteria jo sludge ke mare hue bacteria aur fungi ko todte hain. Unki waste gases, zyadatar methane ke saath carbon dioxide aur thoda hydrogen sulphide, biogas banati hain (Section 8.4); kyunki methane ek fuel hai, kai plants ise apne digesters garam karne ya electricity banane ke liye jalaate hain. Is beech secondary settling tank ke upar ka saaf paani, jiska BOD ab kam hai, nadi ya stream mein wapas jaata hai, aksar disinfection ke baad, ya parks aur industry mein reuse ke liye aur treat kiya jaata hai.

Activated sludge process 1914 se hai, jab ise Manchester, England mein develop kiya gaya tha, aur yeh aaj bhi duniya bhar mein sewage treatment ki reedh ki haddi hai: logon ka banaya koi bhi system itne saare paani ko microbes jitna sasta saaf nahi karta. India ki problem capacity hai. 2021 mein iske shehron ne roz lagbhag 72 000 million litres sewage paida kiya, lekin unke plants iske aadhe se bhi kaafi kam ko treat kar sakte the. Baaki bina treat hue nadiyon tak pahuncha, jisse pollution aur water-borne disease badhi.

Do national programmes India ki sabse jaani-maani nadiyon par is gap ko target karte hain. Ganga Action Plan, jo mid-1980s mein shuru hua, aur 1993 ka Yamuna Action Plan, dono Ministry of Environment and Forests ke under, ne nadiyon ke kinare STPs ki chains ke liye paisa diya taaki shehar ka sewage paani tak pahunchne se pehle hi rok liya jaaye. 2014 mein launch hua Namami Gange programme is koshish ko aur bade scale par aage badhata hai.

8.4 Biogas ke Production mein Microbes

STP ke sludge digesters mein microbes kachre ko fuel mein badalte hain. Yahi cheez chhote scale par poore India mein hazaaron gaon ke gharon ke paas bhi hoti hai.

Is chapter mein ab tak mili gases ko yaad karo: idli batter, Swiss cheese aur brewer ka fermentor, sabne carbon dioxide chhodi. Biogas alag hai, kyunki iska zyadatar hissa methane hai, aur methane sirf microbes ka ek group bana sakta hai: methanogens, jaise Methanobacterium. Yeh sirf wahan rehte hain jahan oxygen nahi hoti, aur doosre microbes ke chhode chhote molecules ko methane mein badalte hain.

Yeh methane do main tareekon se banate hain: hydrogen aur carbon dioxide se, $\mathrm{C}\mathrm{O}{\phantom{X}}_2+4\mathrm{H}{\phantom{X}}_2\stackrel{}{\to }\mathrm{C}\mathrm{H}{\phantom{X}}_4+2\mathrm{H}{\phantom{X}}_2\mathrm{O}$, aur acetic acid ko tod kar, $\mathrm{C}\mathrm{H}{\phantom{X}}_3\mathrm{C}\mathrm{O}\mathrm{O}\mathrm{H}\stackrel{}{\to }\mathrm{C}\mathrm{H}{\phantom{X}}_4+\mathrm{C}\mathrm{O}{\phantom{X}}_2$.

Akele methanogens cellulose ko nahi todte. Gobar aur plant waste mein woh ek chain ki aakhri kadi hain (Fig. 8.10). Kuch bacteria cellulose ko sugars mein todte hain, fermenting bacteria sugars ko acids, hydrogen aur carbon dioxide mein badalte hain, aur methanogens kaam poora karte hain. Hydrogen ko use karke woh pehle ke steps ko bhi chaalu rakhte hain. Sach kahein to methanogens bacteria nahi balki archaea hain, haalaanki tumhari textbook unhe bacteria ke saath rakhti hai.

Gaay-bhains aisi hi chain par depend karti hain. Unka rumen, yaani stomach ka pehla aur sabse bada chamber, microbes ki ek ghani community rakhta hai, jismein methanogens bhi hain, jo ghaas aur bhoose ke cellulose ko ferment karti hai. Animal bane hue acids ko apni energy ke main source ki tarah absorb karta hai aur methane ko dakaar ke saath bahar nikaalta hai. Isliye gobar pehle se in microbes aur aadhe pache plant fibre se bharpoor hota hai, jo use biogas (जैव गैस) ke liye ideal raw material banata hai; India mein ise gobar gas kehte hain.

Gaon ki kitchen se gas ka raasta peeche ki taraf trace karo (Fig. 8.11). Stove ek pipe se steel ke ek bade drum se juda hai jo ulta hokar gobar slurry se bhare gaddhe par tairta hai. Jaise-jaise neeche ke microbes gas chhodte hain, woh drum ke neeche jama hoti hai aur use upar uthaati hai, isliye drum ki oonchai batati hai ki kitna fuel store hai; drum ka wazan gas ko pipe mein aage bhi dhakelta hai. Yeh floating-drum design hai.

Gaddha khud hi digester hai, concrete se line kiya hua lagbhag 3–4.5 m (10–15 feet) gehra tank. Har din parivaar taaze gobar ko lagbhag utne hi volume ke paani mein milata hai, aksar kitchen aur khet ka kachra bhi daalta hai, aur slurry ko inlet pipe se andar daalta hai. Hawa se band hone ki wajah se tank mein poori anaerobic chain chalti hai. Digest hui slurry doosri taraf ke outlet se bahar dhakeli jaati hai; iska carbon to chala jaata hai lekin nitrogen ya phosphorus bahut kam ghatta hai, isliye yeh kheton ke liye bharpoor manure hai.

Aise plants sabse zyada gaon mein kaam ke hain: wahan gobar bahut milta hai, aur khaana banane aur roshni ke liye dhuen wali lakdi aur uplon ki jagah ek saaf neeli flame le leti hai. Do Indian institutions ne is technology ko shape diya: Indian Agricultural Research Institute (IARI), jiske scientists ne shuruaati gobar gas plants banaye, aur Khadi and Village Industries Commission (KVIC), jiska floating-drum design 1960s se poore desh mein phaila. Phir Deenbandhu jaise saste fixed-dome designs aaye, aur 2018 mein launch hui GOBARdhan scheme ab gaon aur community plants ko support karti hai. Agar tumhare school ke paas koi plant hai, to uske maalikon se poochho ki woh roz kitna gobar daalte hain aur yeh kitne logon ka khaana banata hai, aur neeche ke worked example se compare karo.

8.5 Biocontrol Agents ke roop mein Microbes

Kisaan apni fasal ka bada hissa insects, weeds aur plant diseases ki wajah se kho dete hain, aur aam jawab chemicals rahe hain: insecticides, fungicides aur weedicides. Inmein se kai apne target se zyada ko zeher dete hain: unhe spray karne wale farm workers, gaay-bhains aur birds, aur fasalon ko pollinate karne wali bees. Residues soil mein reh jaate hain, kuon mein ris jaate hain aur hamari plates tak pahunchte hain, jabki baar-baar spray ke baad bache pests resistant santaan paida karte hain.

Biocontrol (जैव नियंत्रण) khet ko alag nazar se dekhta hai. Ek organic farmer use ek ecosystem ki tarah dekhta hai jismein pests aapas mein interact karti kai species mein se bas kuch hain. Maksad pests ko khatam karna nahi, balki predators, parasites aur diseases ke jaal ke zariye unhe us level se neeche rakhna hai jahan woh asli nuksaan karte hain. Unhe khatam karna na practical hoga na samajhdaari: pests ka shikaar karne wale ladybirds, wasps aur spiders unke bina bhookhe mar jaayenge. Khet ke andar aur aas-paas jitni zyada tarah ki life hogi, yeh checks utne hi steady honge.

Isliye biocontrol khet ke survey se shuru hota hai: wahan kaun si species rehti hain, kaun pests hain aur kaun unka shikaar karti hain, har ek kab dikhti hai aur kahan chhupti hai. Jo kisaan, maan lo, dekhta hai ki ladybird larvae mustard ki fasal mein aphids ke ek hafte baad aate hain, woh spray rok kar unhe kaam karne de sakta hai, ya sahi waqt par aur natural enemies chhod sakta hai.

Kuch biocontrol agents animals hain. Laal-kaala ladybird beetle aphids khaata hai, yaani woh chhote sap choosne wale insects jo nayi shoots par bheed lagate hain. Dragonflies mosquitoes ko pakadti hain, udte adults ke roop mein bhi aur paani ke andar ke nymphs ke roop mein bhi, jo mosquito larvae khaate hain.

Microbes bhi ismein shaamil hain. Sabse mashhoor soil bacterium Bacillus thuringiensis, yaani Bt, hai, jo spores banate waqt ek protein ko crystals mein pack karta hai. Crystals tab tak harmless rehte hain jab tak woh caterpillar ke alkaline gut tak nahi pahunchte, jahan woh ghulkar ek active toxin ban jaate hain jo gut lining mein chhed kar deta hai; larva khaana band kar deta hai aur kuch dinon mein mar jaata hai (Fig. 8.12). Bees, ladybirds, doosre insects aur insaanon mein yeh trigger nahi hota, isliye unhe nuksaan nahi hota. Kisaan Bt ko spores aur crystals ke powder ki tarah khareedte hain, paani mein gholte hain aur jahan bhi caterpillars kha rahe hon wahan spray karte hain: cabbage, cauliflower aur doosre brassicas par, ya fruit trees par.

Scientists ek kadam aage gaye hain aur Bt toxin gene ko crop plants mein daal diya hai, jo phir apni pattiyon mein khud toxin banate hain. India mein 2002 se ugaya ja raha Bt cotton iska sabse jaana-maana example hai; yeh kaise banta hai, tum Chapter 10 mein dekhoge.

Plant roots ke aas-paas ek fungus rehta hai jo doosre fungi ka shikaar karta hai: Trichoderma. Yeh root rot, wilt aur damping-off karne wale fungi ke threads ke around lipat kar unhe digest kar leta hai, aur jagah aur khaane ke liye unse compete bhi karta hai. Trichoderma se seed aur soil treatment ab India mein bahut use hota hai.

Insects ko bhi viral diseases hoti hain, aur unmein se kuch viruses ab farm tools hain. Baculoviruses sirf insects aur unke arthropod rishtedaaron ko infect karte hain; pest control ke liye beche jaane wale zyadatar genus Nucleopolyhedrovirus (NPV) ke hain. Inki sabse badi taakat precision hai. Ek NPV ek pest species ya kuch kareebi rishtedaaron ko maarta hai, aur tests mein yeh crops, fish, birds, mammals aur doosre insects ke liye harmless paaya gaya hai. Integrated pest management (IPM) follow karne wale kisaan ise isliye pasand karte hain kyunki pests ke natural enemies spray ke baad bhi bache rehte hain, aur ecologically sensitive areas ke managers bhi, jahan koi broad zeher bahut nuksaan karega.

8.6 Biofertilisers ke roop mein Microbes

Chemical fertilisers ne India ko kaafi food ugaane mein madad ki, lekin zyada use ki keemat hai. Daali gayi nitrogen ka bada hissa baha kar nadiyon aur ground water mein chala jaata hai, algal blooms ko badhata hai aur kuon mein nitrate levels badhata hai, aur saalon ke overuse se soil mein organic matter aur life kam ho sakti hai. Isne kai kisaanon ko organic farming ki taraf dhakela hai, jo biofertilisers (जैव उर्वरक) par depend karti hai.

Biofertilisers microbes ke teen groups se aate hain: bacteria, fungi aur cyanobacteria (Fig. 8.13).

Hawa ka 78 % nitrogen gas hai, lekin plants ise is form mein use nahi kar sakte. Rhizobium bacteria leguminous plants, jaise pea, gram, groundnut aur soybean, ki roots mein ghuste hain aur phooli hui root nodules ke andar rehte hain. Wahan woh atmospheric nitrogen ko ammonia mein badalte hain, jisse plant amino acids banata hai, aur badle mein unhe sugars milti hain. Azotobacter aur Azospirillum yahi kaam bina host ke karte hain: woh soil mein free rehte hain ya root surfaces par dheele se chipke rehte hain, aur unki fix ki gayi nitrogen us soil ko bharpoor karti hai, chaahe usmein koi bhi fasal ugaayi jaaye.

Roots ko fungi se bhi madad milti hai. Mycorrhiza (कवकमूल) mein mehin fungal threads, aksar genus Glomus ke, roots ke andar ya around ugte hain aur soil mein root ki apni pahunch se kahin aage tak phail jaate hain. Soil mein phosphorus kam hota hai aur dheere move karta hai; threads ise ikattha karke plant ko de dete hain. Fayde yahin khatam nahi hote: mycorrhizal plant root pathogens se behtar bachta hai, sookhe aur namkeen soil mein behtar zinda rehta hai, aur bas zyada bada ugta hai.

Paani bhare paddy fields ke apne nitrogen suppliers hain: cyanobacteria (blue-green algae) jaise Anabaena, Nostoc aur Oscillatoria. Yeh photosynthetic microbes uthle, dhoop wale paani mein aur geeli soil par khoob badhte hain, aur inmein se kai hawa se nitrogen fix karte hain. Jab yeh marte aur sadte hain to organic matter chhodte hain jo soil ko behtar banata hai, isliye paddy kisaan ko dohra fayda hota hai.