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The aim of this work was to evaluate the treatment of cattle manure with phytases stabilized in allophanic nanoclays as a potential novel phosphorus (P) biofertilization technology for crops grown in volcanic soils (Andisol). Furthermore, because the optimal pH for commercial phytase catalysis does not match the natural pH of manure, a complementary experiment was set up to evaluate the effect of manure inoculation with an alkaline phytase-producing bacterium. Finally, phytase-treated soil, manure, and soil-manure mixtures were evaluated for their P-supplying capacity to wheat plants grown under greenhouse conditions. Treating cattle manure with phytases stabilized in nanoclays resulted in a significant ( P ≤ 0.05) increase of inorganic P in soil extracts (NaOH-EDTA and Olsen). The use of phytase-treated cattle manure increased dry weights by 10 % and the P concentration by 39 % in wheat plants grown under greenhouse conditions, which is equivalent to a P fertilizer rate of about 150 kg of P per hectare. The inoculation of cattle manure with β-propeller phytase-producing bacteria led to an ∼10 % increase in inorganic P in the manure extracts. However, applying inoculated manure to soil did not significantly increase wheat yield or P acquisition responses. Our results suggest that the novel approach of incubating cattle manure with phytases stabilized in nanoclay enhances the organic P cycling and P nutrition of plants grown in P-deficient soils. [ABSTRACT FROM AUTHOR]

To identify plant growth promotion ability of phosphorus-solubilizing native bacteria, we have examined a collection of isolates representing the diversity of culturable phosphate-solubilizing bacteria from acid soils of the northeast of Argentina. Assays in growth medium supplemented with tricalcium phosphate revealed different phosphorus solubilization activity and temporal patterns of solubilization. Acidification of the broth medium coincided with phosphorus solubilization. The isolates were grouped according to their Rep fingerprinting profiles and phylogenetically classified by 16S rDNA and biochemical analyses. These isolates were assigned to the genera Enterobacter, Pantoea, Pseudomonas, Acinetobacter, Burkholderia, and Exiguobacterium. Four isolates showing high phosphorus solubilizing activity in in vitro assays were inoculated on common beans ( Phaseolus vulgaris); some of them promoted plant growth and increased photosynthesis and the P and N content of leaves. The results indicated that the ability to in vitro solubilize P is not necessarily associated to the promotion of plant growth. [ABSTRACT FROM AUTHOR]