Organic Phosphorus Substantially Contributes to Crop Plant Nutrition in Soils with Low Phosphorus Availability

To evaluate phosphorus (P) availability and the role of microorganisms in P dynamics barley rhizosphere, we constructed a rhizobox using two arable Andosols under different fertilization management regimens cultivated (Hordeum vulgare L. cv. Minorimugi) for 5 weeks. The phosphatase-labile pool organic (Po) was assessed phosphatase-addition approach combination with chemical extraction Po from soils. A considerable amount inorganic (Pi) NaHCO3 fraction taken up by roots soil high Pi availability, whereas Po, primarily phytate-like fraction, hydrolyzed then low availability. No significant utilization either NaOH-Pi or NaOH-Po observed both soils during 5-week cultivation. In elevated acid phosphomonoesterase phosphodiesterase activities, greater substrates bacteria Biolog ECO plate, were rhizosphere when compared those bulk soil. This suggested enhanced hydrolysis increased phosphatase activities to meet demand, making an important source