Organic phosphorus (Po) hydrolysis by microbial phytases has extensively been considered in diverse biotechnological applications, including environmental protection and agricultural, animal, and human nutrition. The authors review the available information on the content of phytase-labile Po in manures and soils, as well as the environmental factors and enzyme properties affecting catalytic behavior of phytases in these environments. In addition, they have critically analyzed the present and possible future biotechnological approaches for using phytases to access phytate Po pool present in soils and manures for plant nutrition, with the concomitant reduction of runoff P in the environment.