▁and ▁the ▁gun ▁greatly ▁expanded ▁the ▁killing ▁power ▁of ▁the ▁pla ins ▁N atives . ▁This ▁was ▁followed ▁by ▁the ▁policy ▁of ▁ind isc rim inate ▁killing ▁by ▁European ▁Americans ▁and ▁Canad ians , ▁and ▁caused ▁a ▁dram atic ▁drop ▁in ▁b ison ▁numbers ▁from ▁millions ▁to ▁a ▁few ▁hundred ▁in ▁a ▁century ' s ▁time , ▁and ▁almost ▁caused ▁their ▁ext inction . ▁ ▁Farm ing ▁and ▁ran ch ing ▁ ▁The ▁very ▁dense ▁soil ▁pl ag ued ▁the ▁first ▁European ▁sett lers ▁who ▁were ▁using ▁wooden ▁p low s , ▁which ▁were ▁more ▁suitable ▁for ▁loose ▁forest ▁soil . ▁On ▁the ▁pra irie , ▁the ▁p low s ▁b ounced ▁around , ▁and ▁the ▁soil ▁stuck ▁to ▁them . ▁This ▁problem ▁was ▁solved ▁in ▁ 1 8 3 7 ▁by ▁an ▁Illinois ▁black sm ith ▁named ▁John ▁De ere ▁who ▁developed ▁a ▁steel ▁m old board ▁p low ▁that ▁was ▁stronger ▁and ▁cut ▁the ▁roots , ▁making ▁the ▁fert ile ▁so ils ▁ready ▁for ▁far ming . ▁ ▁The ▁tall gr ass ▁pra irie ▁has ▁been ▁converted ▁into ▁one ▁of ▁the ▁most ▁int ensive ▁c rop ▁producing ▁areas ▁in ▁North ▁America . ▁Less ▁than ▁one ▁t enth ▁of ▁one ▁percent ▁( < 0 . 0 9 %) ▁of ▁the ▁original ▁land cover ▁of ▁the ▁tall gr ass ▁pra irie ▁bi ome ▁remains . ▁States ▁formerly ▁with ▁land cover ▁in ▁native ▁tall gr ass ▁pra irie ▁such ▁as ▁Iowa , ▁Illinois , ▁Minnesota , ▁Wisconsin , ▁Neb r aska , ▁and ▁Missouri