Effect of C-sources and urea on the available N-content and urease activity of a calcareous sandy soil

Summary In a model experiment the adding of urea to a calcareous sandy soil generally increased the available N-content of soil samples. This process is most characteristic in case of urea-treatment without C-sources. The application of C-sources together with urea decreased the rate of mineralization of organic N. Using of C-sources without N-source increased the rate of microbial immobilization of soil N. These conclusions were suggested by measuring microbial number and the urease activity as well.