Provided herein are compositions and methods for controlling enzyme-induced urea decomposition attendant to the application of solid or liquid urea-containing fertilizers to soils. More particularly, the subject matter disclosed herein is concerned with selected triarylmethane compounds as urease inhibitors and their use, either alone or in combination with tetrapolymer synergists. Further, the disclosed compositions have good storage stability, long-lived activity in soil, and avoid the toxicity issues common with present-day urease inhibitors used in agriculture.