THE MICROBIAL TRANSFORMATION AND UTILIZATION OF SPARINGLY SOLUBLE PHOSPHATE IN CALCAREOUS SOILS

Phosphrus, one of the three key plant nutrients, plays an important role in plant growth. Currently, a large amount of soluble P fertilizer is used to supply plants with adequate available phosphorus. However, P can quickly react with soil components after applied in fields because of its high chemical activity, and become less soluble or adsorbed by the soil and can not be available to plants. It was estimated that more than 80% of applied P fertilizer become sparingly soluble phosphate and retained in calcareous soil. One of the important approachs to solve this problem is to use the biological system involved in P cycle in plant rhizosphere to regulate the availability of P in soil. The absorption and utilization of P by plants and by some microorganisms with high P-solubilizing ability in soils were included in this biological system. Current advance in the transformation and utilization of sparingly soluble phosphate by microorganisms (bacteria and fungi) in calcareous soils was reviewed in this artice.