Changes in Phosphorus Fractions and its Availability Status as Affected by Appling of Bio and Mineral Fertilizers in The Calcareous Soils

Document Type : Original Article



2 Desert Research Center


The important main reason to enhance the studied calcareous soil and support changes of phosphorus fractions to reach to availability status for plant uptake. Two kinds of phosphate solubilization bacteria (PSB), (Lysinibacillus boronitolerans and Bacillus megatherium) were used to reach this target. The greatest significant results of labile P % in soil were obtained by employing a 75% P with (L. boronitolerans) treatment and 75% P with (B. megatherium + L. boronitolerans) treatment. The combine (B. megatherium and L. boronitolerans) treatments with (P50) or (P75) were superior in increasing labile phosphorus compared to other treatment alone. The results revealed that (PSB) treatments and also P rates affect significantly soil pH values compared to control where the highest pH decrease was showed in soil treated with combine (PSB) treatment either with (P50), or (P75).

boronitolerans produced acidic phosphatase enzyme and produced alkaline phosphatase enzyme. B. megatherium doesn't produced acidic phosphatase enzyme, but produced alkaline phosphatase enzyme. L. boronitolerans produced many kinds of organic acids, while B. megatherium produced all of them except butyric acid. Treatment of 75% P with (L. boronitolerans + B. megatherium) gave high results of Spinach lengths, shoot weights, P (%), Chlorophyll A & B, Vitamins A, B, C and E., Nitrogen fixers, PSB, total microbial counts and soil Dehydrogenase enzyme.

We recommend using treatment of 75% P with (L. boronitolerans + B. megatherium) to release P in calcareous sandy soils and increase crop productivity.  


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