Effects of Applyingthe New Controlled-release Urea to Soils of Different Fertility on the Urease Activity

The determination of urease activity and ammonia volatilization and its comparison of dynamic changes within seven days were done in this paper by applying four different controlled-release urea to soils of high, medium and low fertility with the successive incubation diffusion utensil and soil simulation incubation.The quantum of ammonia volatilization reduced greatly in all treatment. But in soils of different fertility,inhibiting speed and extend of the urease activity and release rate of the two ureases were different as well as the quantum and rate of ammonia volatilization .The soils of high and medium fertility were much more profitable both in economy and in environment. By contrast, it depended on the idiographic soil that if the controlled-release urea containing incubation agent and what type of controlled-release urea should be applied to the low fertility soil.