Background The inhibitor regulation technology of urease activity is one of the most effective biochemical methods to improve urea utilization, the Schiff base complex type urease inhibitors with double active sites belong to the fourth type of urease inhibitors(C₁₅H₁₄N₃O₂SClCu, FTUI). The purpose of this study is to investigate the effects of FTUI on urease activity and soil microbial diversity, so as to reveal the microbiological effects of these urease inhibitors and fully develop their potential value.

Methods A copper (Ⅱ) complex containing Schiff base was synthesized by a two-step synthesis method at room temperature, and characterized by melting point apparatus, infrared spectrometer and synchronous thermal analyzer. 5-point method was used for collecting soil samples. Indophenol blue colorimetric method and dilution coating plate counting method were used to test the enzyme activity and its toxic effect on soil microbial biomass, and Origin and SPSS software were used for data processing.

Results For complex FTUI, results showed that the inhibitory effect of the complexes on jack bean urease activity was significantly higher than that of commercially available acetohydroxamic acid (C₂H₅NO₂). The soil urease activity was strongly inhibited in the low concentration range of 0.1%-1.0%, and the inhibitory effect increased with the increase of concentration, and the highest inhibition rate was 71.20%. Meanwhile, FUTI had a certain promoting effect on the growth of soil bacteria, actinomycetes and fungi, and the highest growth rate reached 60.30%, 71.71% and 1 592.85%, respectively, and it effect on fungi was more sensitive.

Conclusions FTUI has a good inhibitory effect on the urease and soil urease, and promotes the growth of soil microorganisms, and the effect is most significant when the concentration is 1.0%.