Evaluation of the status of P fractions and their relationships with selected soil properties in some calcareous soils

الملخص EN

Effective soil phosphorus (P) management requires the understanding of P forms and its availability.

The amount and distribution of P in different fractions of 15 soil samples of Fars province, Iran were determined by sequential extraction methods.

The relationships of the P distribution among each other and with soil characteristics were investigated.

Total P of different soils ranged from 349 to 994.3 cmol.kg-1.

The clay contents of different samples ranged from 18% to 53%, CEC from 8.5 to 24.9 (cmol(+)kg-1) and the CCE from 20.6% to 64%.

The amount of different P forms Ca2-P (dicalcium phosphates), Ca8-P (octacalcium phosphates), Al-P (Alphosphates), Fe-P (Fe-phosphates) and P as Ca10-P (apatite) were determined.

The relative abundance of other inorganic P forms was in the order of Ca10 – P > Ca8- P > Al –P> Fe-P>Ca2-P > Occl-P.

Simple correlation coefficients showed that Olsen-P had a significant correlation with total-P, Ca2-P, Ca8-P and Al-P.

A Significant correlation was also observed between the P forms, which is presumably a reflection of the existence of a dynamic relation between the chemical forms of Phosphorus in soil.

Clay with total-p and Apatite; total P with Olsen, Al-P and Organic-P; CEC with total-P and Organic-P have positive significant correlation.

Sand with Ca10-P and Al-P; organic-p and Al-P with pH have negative significant correlation.