Improving the Efficiency of Inorganic Phosphorus as Affected by Phosphate Dissolving Bacteria Under Calcareous Soils

Abstract

RD).The results revealed that PDB inoculation increased their population in soil and significantly increased the availability of P in calcareous soil whether applied alone or combined with added P forms compared without it, where the treatments of TSP at 75 and 100% RD combined with PDB gave the highest percentage (125.8, 136.4%) at the 50 days age and the lowest percentage (50.9, 53.3%) at harvest, respectively. The results indicated to increase macronutrients uptake by faba bean plants, which positively reflected on quantities and qualities of yields. It can be concluded that adding TSP at 75% RD combined with PDB inoculation is the recommended for improving the productivity of faba bean crop, while the means values of seed yield relatively increased about with 41.4% over the same treatment without PDB and about 34.2, 36.9% for PDB inoculation and TSP forms as individual effect respectively. It was noticed that the PDB-inoculated seeds increased phosphorus use efficiency (PUE), phosphorus agronomic efficiency (PAE) and phosphorus recovery efficiency (PRE) by about 33.04, 101.1 and 138.1%, respectively over the uninoculated. Triple superphosphate (TSP) has the greater efficiency whether it was alone or combined with PDB inoculation at 75% RD addition compared to other forms. Key word: calcareous soil, mineral P forms, phosphate dissolving bacteria (PDB), faba bean.