Estimation of The availability of P fractions for bean (Phaseolus vulgaris) in some calcareous soils

Soil Sustainable management requires comprehensive information about the amount and form of phosphorus (P). The objective of thisresearch was to evaluate the relationship of various P fractions in 10 calcareous soils of Chaharmahal-Va-Bakhtiari province with bean indices growing in the greenhouse. Thus, P fractions, including P absorbed by Al and Fe oxides (]NaOH+CB]-P), occluded P (CBD-P) and P absorbed by Ca (HCl-P), were determined by Olsen and Summer's sequential fractionation procedure. Furthermore, organic P was determined. A pot experiment in 10 soils with three replications was conducted to evaluate the bean plant indices. After the bean plants harvested, plant indices such as dry yield, P concentration and P uptake were determined. The results showed that the amount of P fractions increased in the order of HCl-P>residual-P>PO>]NaOH+CB]-P >CBD-P. The significant correlations were found between CB-P, OP and CBD-P and plant indices. Thus, P fractionation method appears to be a powerful tool to identify the P status and availability in the studied soils.