MICROBIAL FERMENTATION TO IMPROVE ELEMENTS AVAILABILITY OF SOME ROCKS FOR AGRICULTURAL APPLICATION

Abstract

Inorganic phosphate (P) and potassium (K) are major essential nutrient for plant growth and development, however that most soils have low availability. To overcome this problem it is necessary to apply high amounts of P and K fertilizers, however this is inefficient and costly. Insoluble rocks (phosphate or potassium) are a natural, cheap and clean compound but unfortunately it is a poor P or K fertilizer which may be converted to soluble by the action of some microorganisms. Therefore, the present work has been focused to study the production of fermented solutions by most rocks solubilizing microbial strains in order to use in some agricultural applications. Some microorganisms are capable of accelerate the dissolution of RP in their fermented solutions produced and namely P- solubilizing microorganisms (PSM). In order to improve the biotechnological application of PSM in fertilizer industry to either produce more soluble P fertilizer or enhance the effectiveness of the direct use of RP as P fertilizer, it is necessary to know the impact of some critical factors. The study included isolation, selection and identification of the most efficient phosphate and potassium solubilizing microorganisms, detection of some nutritional and environmental factors supporting their efficiencies to solubilize phosphate. A part of the study was carried out to use some available agro-industrial residues as cheap substrates for phosphate solubilization in order to production of fermented solution from RP using submerged culture. The fermented solution produced was applied as a mineral source for microbial growth and foliar spray fertilizer for agricultural bean.