A composition comprising: (A) a mixture comprising at least one (thio)phosphoric acid triamide according to the general formula (I) R1R2N—P(X)(NH2)2, wherein X is oxygen or sulfur; R1 is a C1 to C20 alkyl, C3 to C20 cycloalkyl, C6 to C20 aryl, or dialkylaminocarbonyl group; R2 is H, or R1 and R2 together with the nitrogen atom linking them define a 5- or 6-membered saturated or unsaturated heterocyclic radical, which optionally comprises 1 or 2 further heteroatoms selected from the group consisting of nitrogen, oxygen, and sulfur, and (L1) at least one amine selected from the group consisting of (L10), (L11), (L12), (L13), (L14), (L15), (L16), (L17), (L18), (L19), (L20), (L21), (L22), (L23), (L24), and (L29).