The possible use of scarce soluble materials as a source of phosphorus in Vicia faba L. grown in calcareous soils

Abstract

Phosphorus (P) is affected by many factors that minimize its solubility especially in calcareous soils. The aim of this work was to conduct laboratory and greenhouse experiments to study the effect of using P solubilizing substances, i.e., compost, humic acid (HA), citric acid and ethylene di-amine tetra acetic acid (EDTA), and rhizobacteria, Bacillus megaterium var. phosphaticum on solubilizing P from different sources, ordinary superphosphate (OSP), rock phosphate (RP) and basic slag (BS). The effect of these treatments on the P- availability in El-Nubaria calcareous soil and P- uptake by faba bean (Vicia faba ‘Giza 843’) were studied. Obtained results showed that the solubility of P sources differs in their ability to release soluble P in the following order: OSP > RP > BS. The following descending order was appeared of available P in soil with addition of solubilizing agents: citric acid > EDTA > HA > compost for these sources of P, for both experiments. Regarding the interaction between solubilizing agents, the treatments of HA combined with EDTA or citric acid were superior in giving high concentrations in soil, and vigor plant growth. In addition, the solubility of P increased by about 5-6 times for all sources in the presence of P- dissolving bacteria. It seemed that the presence of appreciable amounts of Mg, S, Fe, Mn, B and other elements in BS played a role in enhancing plant growth and increasing yield, especially in the presence of added bacteria. BS could be used in calcareous soils and for soils characterized by low nutrient supply as sandy.

Keywords

• phosphorus sources
• basic slag
• organic substances
• chelating substances
• P availability
• P dissolving bacteria