Abstract: Fertilizers containing urea with urease inhibitors, wherein the urease inhibitors are bromo-nitro compounds having the formula: ##STR1## wherein A.sub.1 is (CH.sub.2).sub.n.sbsb.1 X.sub.1, and A.sub.2 is (CH.sub.2).sub.n.sbsb.2 X.sub.2, wherein both n.sub.1 and n.sub.2 and X.sub.1 and X.sub.2 are the same or different, the alkyl groups of A.sub.1 and A.sub.2 are straigh-chain or branched-chain alkyl groups, and the substituents X.sub.1 and X.sub.2 are attached to any one of the carbon atoms of the alkyl groups, and n.sub.1 and n.sub.2 are 0 to 6, X.sub.1 and X.sub.2 are H or YR, wherein Y is --O--, --S-- or --NH-- and R is H or a straight or branched chain C.sub.1 -C.sub.6 alkyl, cyclopent(en)yl cyclohex(en)yl or phenyl group having one to three methyl groups or ##STR2## attached thereto, and R.sub.1 is H or a straight or branched chain C.sub.1 -C.sub.6 alkyl, cyclopent(en)yl or cyclohex(en)yl group having one to three methyl groups or ##STR3## attached thereto.