Relationship Between Phosphatase Activity and Phosphorus Fractions in Agricultural Soils

Abstract

Soil phosphatases play a major role in the mineralization processes of organic phosphorus. The activity of soil phosphatases can be influenced by numerous factors and soil physico-chemical properties play a key role among them. Our research adds to the growing knowledge on soil acid (ACPA), neutral (NEPA) and alkaline phosphatase with some soil properties and total P (P <inf>total</inf>), organic P (P<inf>org</inf>), bioavailable P and inorganic phosphorus (P<inf>inorg</inf>) fractions such as soluble and loosely bound phosphorus (P<inf>soluble</inf>), aluminum phosphates (Al-P), iron phosphates (Fe-P), reductant soluble phosphorus (P<inf>reductant</inf>) calcium phosphates (Ca-P) and strongly adsorbed Fe and Al phosphates (Fixed-P) fractions in agricultural soils of Çarşamba Plain, Turkey. ALPA, 24.6-138.6 μg phenol g-1 3 h-1, was significantly higher than NEPA, 11.5-84.1 μg phenol g-1 3 h-1 and ACPA, 8.6 - 64.1 μg phenol g-1 3 h-1, in the studied soils. P <inf>total</inf> contents in the soils ranged from 400.8 - 745.0 μg P g -1 with an average 570 μg P g-1. Phosphorus was mostly concentrated in the P<inf>inorg</inf> (57%) although it was also present in P<inf>org</inf> (12%) and P<inf>residual</inf> (31%). On the average, percent of P<inf>inorg</inf> associated with different fractions in these soils was in the decreasing order of: Ca-P > Fixed-P > P<inf>reductant</inf> > Al-P > Fe-P > P<inf>soluble</inf>. On the basis of results obtained in this study, phosphatase activies showed significant correlations with the P <inf>total</inf>, P<inf>org</inf>, bioavailable P and some P<inf>inorg</inf> fractions (Ca-P and P<inf>soluble</inf>). These results suggested that Ca-P is major P<inf>inorg</inf> compound on the effects of soil phosphatase activity in agricultural soils of Çarşamba Plain, Turkey. © 2007 Academic Journals.