aparadan
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is lekh mein sandarbh ya sootr naheen diye gaye hain. krupaya vishvasaneeya sootron ke sandarbh jodkar is lekh mein sudhaar karein. bina sootron ki saamagri ko hataaya ja sakta hai. (December 2011) |
mruda aparadan (Erosion) ya bhooksharan us praakrutik prakriya ko kehte hai jismein mitti ki upari parat jal ya vaayu ke tej bahaav ke kaaran ud jaati hai. praakrutik kaaranon se pruthveeprushth ke kuchh anshon ke sthaanaantaran ko aparadan kehte hain. kaaran taap ka parivartan, vaayu, jal tatha him hain. inmein jal mukhya hai.
yeh un logon ke liye ek gambhir samasya hai jo log fsal ugaana chaahate hain. jab bhooksharan hota hai to fsal achhi naheen hoti kyonki iske kaaran mitti ki upajaaoo upari parat ud ya bah jaati hai.
bhooksharan se na keval kheti karne ke kaam mein pareshaani aati hai, balki anya samasyaaen bhi iske kaaran ho sakateen hain, jaise bhoomi par bade-2 gaddhe padna jinke kaaran kisi bhavan ki neenv nirbal ho sakti hai aur bhavan dhah tak sakta hai.
parichay
samudratat par laharon aur jvaarabhaata ki kriya ke kaaran pruthvi ke bhaag tootakar samudra mein vileen hote jaate hain. mitti athva komal chattaanon ke sivaaya kadi chattaanon ka bhi in kriyaaon se dheere dheere apakshaya hota rahata hai. varsha aur tushaar bhi is kriya mein sahaayak hote hain. varsha ke jal mein ghuli hui gaison ki raasaayanik kriya ke falasvaroop, kadi chattaanon ka apakshaya hota hai. aisa jal bhoomi mein ghuskar adhik vileya padaarthon ke kuchh ansh ko bhi ghula leta hai aur is prakaar alagn hue padaarthon ko baha le jaata hai.
varsha, pighli hui thos barf aur tushaar nirantar bhoomi ka ksharan karte hain. is prakaar toote hue ansh naalon ya chhoti nadiyon se badi nadiyon mein aur inse samudra mein pahuainchate rahate hain.
nadiyon ka athva anya bahata hua jal kinaaron tatha jal ki bhoomi ko kaatkar, mitti ko ooainche sthaanon se neeche ki or baha le jaata hai. aisi mitti bahut bade parinaam mein samudra tak pahuainch jaati hai aur samudra paatane ka kaam karti hai. samudra mein girnevaale jal mein mitti ke sivaaya vibhinn prakaar ke ghule hue lavan bhi hote hain.
din mein dhoop se tapt chattaanon mein padi daraarein fail jaati hain tatha unamein ade patthar neeche sarak jaate hain. raat mein thand padne ya varsha hone par chattaanein sikudti hai aur daraaron mein pade pattharon ke kaaran daraarein aur badi ho jaati hai. sheetapradhaan deshon mein inheen daraaron tatha bhoomi ke andar rikt sthaanon mein jal bhar jaata hai. adhik sheet padne par jal him mein parivrtit ho jaata hai aur tab un sthaanon ya daraaron ko faadkar tod deta hai. in kriyaaon ke baar baar doharaae jaane se chattaanon ke tukade tukade ho jaate hai. in tukadon ko jal aur vaayu anya sthaan par le jaate hain. jin pradeshon mein din aur raat ke taap mein adhik parivartan hota hai vahaaain ki mitti nirantar prasaar aur aakunchan ke kaaran dheeli ho jaati hai evam vaayu athva jal dvaara anya sthaanon par pahuainch jaata hai. shushk praanton mein, jahaaain vanaspati se dhanki naheen hoti, vaayu apaar baalukaaraashi ek sthaan se doosare sthaan ko le jaati hai. is prakaar sahaara marubhoomi ki ret, ek or saagar paar sisili dweep tak aur doosari or Nigeria ke samudra tat tak, pahuainch jaati hai. vaayu dvaara udaaya hua baaloo dhoohon athva ooainchi chattaanon ke komal bhaagon ko kaatkar unki aakruti mein parivartan kar deta hai. jal mein baha hua padaarth sada ooainche sthaan se neeche ko hi jaata hai, kintu vaayu dvaara udaai hui mitti neeche sthaan se ooainche sthaanon ko bhi ja sakti hai.
gatisheel him jin chattaanon par se hokar jaata hai unka ksharan karta hai aur is prakaar mukt hue padaarth ko apne saath liye jaata hai. vaayu tatha nadiyon ke kaarya ki tulana mein, dhruv pradesh ko chhodkar pruthvi ke anya bhaagon mein, him ki kriya alp hoti hai.