mruda vigyaan

vibhinn prakaar ki mruda ke namoone

mruda vigyaan (Soil science) mein mruda ka adhyayan ek praakrutik sansaadhan ke roop mein kiya jaata hai. iske antargat mrudaanirmaan, mruda ka vargeekaran, mruda ke bhautik, raasaayanik tatha jaivik gunon ka adhyayan, urvarakata ka adhyayan aadi kiya jaata hai.

mruda vaigyaanik is baat ko lekar chintit hain ki vishv ki janasankhya-vruddhi ke saath mruda tatha kheti yogya bhoomi ka sarakshan kaise kiya jaaya.

anukram

parichay

mitti ko manushya anaadikaal se jaanta hai. dharati, jis par vah hal chalaata hai, khet jismein vah fasalein ugaata hai aur ghar jismein vah rahata hai, ye sabhi hamein mitti ki yaad dilaate hain. kintu mitti ke sambandh mein hamaara gyaan praaya: naheen ke baraabar hai. yeh sabhi jaante hain ki anaaj aur fal mitti mein upajaate hain aur yeh upaj khaad evam urvarakon ke upayog se badhaai ja sakti hai, lekin mitti ke anya visheshataaon ke baare mein, jinse ham sadak, bhavan, dhaavanapath (runway) tatha bandhon ka nirmaan karte hain, hamaara gyaan bahut kam hai.

mitti ke vyavahaar ko bhali prakaar se samajhne ke liye mitti ke raasaayanik aur bhautik sanghatan ka gyaan aavashyak hai.

mruda bhautiki

bhautiki ki drushti se mitti ke teen avayav hain, ret, silt aur mruttika. ret sthool avayav hai, jismein na keshikaatv hota hai aur na sansanjan. ret ke kanon ka aakaar 0.05 mimee0 se 2 mimee0 ke beech hota hai. silt ke kan ret se bhi sookshm hotesh hai. inka aakaar 0.05 mimee0 se 0.002 mimee0 ke beech hota hai. ret aur sil‌aaa donon nishkriya padaarth hain. teesara mahatvapoorn avayav mruttika hai, jiske kan 0.002 mimee0 se chhote hote hain. ret, silt aur mruttika mein pramukh antar yeh hai ki jahaaain ret aur silt nishkriya hote hein, vahaaain mruttika rasaayanat: sakriya hoti hai.

mitti ki banaabat kaafi seema tak in avayavon ki pratishtata par nirbhar hai. ret, silt aur mruttika ki adhikta hone par mitti ko kramash: reteeli, silti aur matiyaar kehte hain. in avayavon ko prati shat nirdhaaran bhautikeeya vishleshan (Mechanical Analysis) kahalaata hai.

reteeli mitti ki banaavat (texture) khuli hoti hai, jisse vaayu sanchaaran paryaapt hota hai aur yadi matiyaar bhaag mein khanij padaartho ki maatra yathesht ho to yeh mitti kheti ke liye adhik upayukt hai. matiyaar mitti sookhane par paryaapt sikudti hai aur paryaapt paani se khoob foolati bhi hai. aisi mitti na to krushi ke liye achhi hoti hai aur na makaan banaane ke liye.

mruda saghanata

khuli banaavat waali mitti saghanata ki kami ke kaaran krushi ke liye achhi hoti hai, kyonki jal atirikt sthalon mein pravisht kar khanij lavanon ko ghula sakta hai; par injeeniyri ke kaam ke liye yeh mitti achhi naheen hoti, kyonki jal pravesh ke kaaran mitti mein saghanata honi chaahiye. mitti jitni saghan hogi, usaki daav prabalata aur drudhta bhi utani adhik hogi. saghanata ka ghanatv (degree of compaction) vastut: aardrata ki maatra par nirbhar karta hai. kisi vishisht prakaar ki mitti ke liye aardrata ki jo pratishtata adhiktam saghanata pradaan karti hai, vah us mitti ki ishtatam aardrata kahi jaati hai. ishtatam aardrata halake rolar ki tulana mein bhaari rolar ke liye kam hoti hai. jis mitti mein nimn aakaar ke kanon ka sanmishran achha hota hai, usaka ghanatv uchchatam hota hai. sanghanit mitti ki prabalata banaae rakhane ke liye yeh aavashyak hai ki paani ke mrudukaran prabhaav ka vah pratirodhak ho. iske liye mitti mein cement, choona, rasaayanak ya bitoomani padaarth milaate hain.

mrud rasaayan

yeh pehle hi bataaya ja chuka hai ki mitti mein pradhaanataya ret, silt aur mruttika rahate hain. inke saath hi usamein kuchh vileya aur kuchh avileya lavan bhi rahate hain, jaise kailsiym tatha maignisheeyam ke kaarbonet aur sodiym evam potaishiym ke kloraaid tatha salfet. anek roopon mein bhinn saandrata ke kaarbanik padaarth bhi rahate hain. ye sabhi mitti ke raasaayanik vyavahaar ko prabhaavit karte hain. jaisa ki pehle bataaya ja chuka hai, ret aur silt nishkriya hain tatha mruttika hi rasaayanat: sakriya hai, at: mitteesh ke raasaayanik gun mruttika par avalanbit hain. mruttika anek tatvon, jaise loh, ailyoominiym, silikn aadi ki jatil sanrachana ke roop mein bani hai. mruttika ke khanij sanmishr ke kuchh gun vilkshan hain. yeh paani mein avileya hota hai, par usamein nilambit avastha mein rah sakta hai. iska nilambit rahana kanon ke aakaar par nirbhar hai. nilambit avastha mein yeh amleeya abhikriya deta hai. iski amlata aiseetik aml ki amlata sadyash hai. is amlata ka udaaseeneekaran kailsiym aur sodiym ke haaidrauksaaid sadyash kisi kshaareeya padaarth se kiya ja sakta hai. iske falasvaroop kailsiym aur sodiym mitteeyaaain banti hain. daanedaar sanrachana ke kaaran kailsichm mitti krushi kesh liye upayukt hai, par sodiym mitti jalaabhedh hone ke kaaran baaaindh aur sadkon ke nirmaan ke liye adhik upayogi hai. mitti dvaara kailsiym ayan avashoshit hokar aisa sthireekrut ho jaata hai ki shuddh jal ke dvaara vah ghulakar nikal jaata par anya lavan se saralata se pratisthaapit ho jaata hai. udaaharan ke liye kailsiym mitti ko jab namak ke vilyan se apakshaalit kiya jaata hai, tab usase sodiym mitti banti hai aur kailsiym ayan kloraaid ke roop mein vilyan mein aa jaata hai. sodiym mitti ko fir kailsiym, ya anya mitteeyon ke vilyan ke saath apakshaalit karne se kailsiym, ya anya dhaatuon ki mitteeyon mein parint kiya ja sakta hai. mitti ke is gun ko, jismein kshaaron ka vinimay hota hai, " mitteesh ka vinimay gun' kehte hain aur vinimay hone wala dhanaayan waali mitteeyaaain hoti hain, jinmein kailsiym, sodiym, potaishiym tatha maingnishiym pramukh hain aur nikel, kobaalt, boran aadi badi alp maatra mein rahate hain, yadyapi paudhon ki vruddhi ke liye ye aavashyak hain. sookshm maatra mein rahane vaale in tatvon ko anuposh "tatv' kehte hain. kisi mrud bhaag mein dhanaayan ka pratishat vinimay dhaarita par nirbhar karta hai, jo maantamaarilonaait koti ki mitti mein adhik aur keolinaait koti ki mitti mein kam hoti hai. maantamaarilonaait koti ki mitti ka udaaharan kapaas waali kaali mitti hai, jo Bhaarat ke Madhya Pradesh, Madras aur Mumbai ke kuchh bhaagon mein faili hui hai. keolinaait mitti saadhaarantaya Bhaarat ke jalodh maidaanon mein pai jaati hai.

haaidrojan aayan saandrata (ph)

jaisa pehle sanket kiya ja chuka hai ki jis mitti mein tanu aml ke upachaar se vinimeya kshaar ka nitaant abhaav hai, usaki haaidrojan aayan saandrata uchchatam hoti hai aur falat: pi H nimnatam hota hai. jyon jyon mitti mein sodiym kailsiym jaise vinimeya ayan milaae jaate hain, tyon tyon usaka pi H badhta jaata hai. mitti ka uchchatam pi H lagbhag 11 tak pahuainch jaata hai. vaastavik kshetr paristhiti mein isse kuchh adhik pi H dekha gaya hai, kintu usaka kaaran vinimeya dhanaayan naheen hain, balki sodiym kaarbonet jaisa vileya lavan hai, jo kshaareeya mitti mein saadhaaranataya rahata hai. aise lavanon ka ek nishchit seema se adhik hona fasalon ki vruddhi ko rokata hai. lekin injeeniyri sanrachana ke liye mitti mein sodiym kaarbonet ka hona laabhadaayak hota hai. in lavanon ki upasthiti mitti ka sodiym mitti mein parint karti hai, jo saadhan avastha mein kailsiym mitti se adhik jal pratirodh karti hai. falat: nam avastha mein bhi mitti ki shakti bani rahati hai, jo injeeniyri sanrachana ke liye aavashyak hai.

mitti ka vargeekaran

nisrg bhoomi ke teen pramukh avayav hain, ret, silt aur mitti. inke kanon ke aakaar mein to antar hai hi, inke raasaayanik tatha bhautik gun bhi bhinn hain.

ret (sand) saadhaaranataya silika aur sfatik ki bani hoti hai. silika aur sfatik nishkriya hote hain. ret ka aakaar 0.06 mimee0 se 2 mimee0 tak hota hai. ret ke kanon mein sansanjan (cohesion) aur keshikaatv (capilarity) naheen hota, kintu paaragamyata (permeability) adhik hoti hai.

silt (silt) ke ghatak silika aur sfatik hi hain, kintu iske kanon ka aakaar 0.0002 mimee0 se 0.06 mimee0 tak hota hai. silt ke kanon mein sansanjan naheen hota, lekin keshikaatv kaafi hota hai.

mitti (clay) ke kanon ka aakaar 0.002 mimee0 se kam hota hai. ret aur silt se iski asamaanata yeh hai ki mitti ke kan rasaayanat: aavisht (chemically charged) hone ke kaaran rasaayanakon s abhikriya karte hain.

mitti ki adhikta se bhoomi mein keshikaatv tatha sansanjan aata hai. aisi bhoomi geeli hone par foolati hai tatha sookhane par sikudti hai.

mitti ke in spasht bhautik gunon ka kaaran usamein kolaayadeeya kanon ki uchch pratishtata hai, jisse haaidrojan, sodiym, kailsiym, potaishiym, maigneeshiym aadi ke ayan prushth se adhishoshit (adsorbed) hote hain. ye ayan vinimeya hain, arthaat vilyan (solution) mein ye doosare ayanon se pratisthaapaneeya (replaceable) hain.

in ayanon ko adhishoshit karne ki uchchatam kshamata ko kshaar ki vinimay dhaarita (base exchange capacity) kehte hain. ayanon ki kshaarak (specific surface area) bhi utana hi adhik hoga. mitti ke gun prushth par adhishoshit dhanaayan (cation) par nirbhar karte hain.

mitti ki sanrachana

bhinn bhinn mitteeyon ke raasaayanik avayav ek hi hain, arthaat maatra mein (MgO), (CaO), (K2O), (Na2O) ke saath (SiO2), (Al2O3), (Fe2O3) tatha jal, kintu bhinnn mittiyon mein khanij yaugik bhinn hote hain. anek vaigyaaniko ke ex kiran tatha sajaateeya shail vishleshan anek vaigyaaniko ke ex kiran tatha sajaateeya shail vishleshan (petrographic) sambandhi prayogon ke falasvaroop mitti khanij ke do samooh nishchit hue hein. vargeekaran ka aadhaar kristal jaalak (crystal lattice) ki banaavat hai.

keolin samooh

dekhein - cheeni mitti

is samooh ke khanij silika aur ailyoomina ke ek ek chaadaron se bane hote hain.

maant maarilonaait samooh

is samooh ke khanij ke kristal jaalak do ikaai silika chaadar aur ek ikaai ailyoomina chaadar se bane hote hain.

kristal jaalak sanrachana ki bhinnata ke falasvaroop in do samoohon ki mittiyon ke raasaayanik tatha bhautik gunon mein mahaan antar hota hai.

keolin khanij ki kshaar viniym dhaarita nimn aur usaka adhishoshan gun bhi kam hota hai, jab ki maantamaarilonaait khanij ka dhanaayan-adhishoshan hota hai.

Bhaarat ke mitti samoohon mein pradhaan kapaas ki kaali mitti, jo praaya: samast madhya tatha dakshin Bhaarat mein chhaai hui hai, maantamaarilonaait samooh ki hai. iska mukhya gun sikudna tatha failana hai, jo bhavan tatha sadak nirmaan ki samasya hai. idhar ki khoj se siddh hua hai ki mote choone (fat lime) se abhikriya karaane par mitti ka foolana bahut kuchh kam ho jaata hain.

inhein bhi dekhein

baahari kadiyaaain