n alkyl pyrrolidone may also be present in small quantities the composition may optionally also contain a suspending agent such as clay as well as other additives such as a herbicide a dye an nbpt stabilizer or a micronutrient silicon dioxide a flow agent is optionally present in an amount of up to about 3 of the dry flowable additive the dry flowable additive prepared without the optional dcd contains about 1 to 80 nbpt and about 99 to 20 solid ufp the dry flowable additive is added to the uan solution aqueous urea or solid or molten urea in the range of about 0 1 to 5 0 additive in the final product preferably the dry flowable additive is added in the range of about 0 4 to 2 5 to fluid uan or urea solution or blends thereof to form a fluid fertilizer the fluid urea based fertilizer of the present invention contains from about 0 004 to 1 50 nbpt from about 0 040 to 0 850 dcd from about 0 030 to about 0 30 ufp and from about 99 9 to 98 0 aqueous uan optionally the fertilizer can contain up to about 0 03 silicon dioxide the aqueous uan contains urea and ammonium nitrate in concentration ranges of about 15 to 50 a preferred range is from about 25.