▁southern ▁parts ▁of ▁the ▁country , ▁the ▁lower ▁Dan ube ▁P lain ▁is ▁divided ▁by ▁the ▁O lt ▁River ; ▁east ▁of ▁the ▁river ▁lies ▁the ▁Roman ian ▁P lain , ▁and ▁to ▁the ▁west ▁is ▁the ▁Ol ten ian ▁or ▁Western ▁P lain . ▁The ▁land ▁here ▁is ▁rich ▁with ▁ch ern oz em ic ▁so ils ▁and ▁forms ▁Roman ia ' s ▁most ▁important ▁far ming ▁region . ▁Ir rig ation ▁is ▁widely ▁used , ▁and ▁mar sh lands ▁in ▁the ▁Dan ube ' s ▁flo od plain ▁have ▁been ▁d ik ed ▁and ▁dra ined ▁to ▁provide ▁additional ▁till able ▁land . ▁ ▁Roman ia ' s ▁lowest ▁land ▁is ▁found ▁on ▁the ▁northern ▁edge ▁of ▁the ▁Dob ru ja ▁region ▁in ▁the ▁Dan ube ▁D elta . ▁The ▁delta ▁is ▁a ▁tri angular ▁sw amp y ▁area ▁of ▁mar sh es , ▁floating ▁re ed ▁islands , ▁and ▁sand b anks , ▁where ▁the ▁Dan ube ▁ends ▁its ▁tre k ▁of ▁almost ▁ 3 , 0 0 0   km ▁and ▁div ides ▁into ▁three ▁f rayed ▁branches ▁before ▁empty ing ▁into ▁the ▁Black ▁Sea . ▁The ▁Dan ube ▁D elta ▁provides ▁a ▁large ▁part ▁of ▁the ▁country ' s ▁fish ▁production , ▁and ▁its ▁re eds ▁are ▁used ▁to ▁manufact ure ▁cell ul ose . ▁The ▁region ▁also ▁serves ▁as ▁a ▁nature ▁preserve ▁for ▁rare ▁species ▁of ▁plant ▁and ▁animal ▁life ▁including ▁mig rat ory ▁birds . ▁ ▁After ▁entering ▁the ▁country ▁in ▁the ▁south west ▁at ▁B