Effect of Continuous Cropping on Phosphorus Adsorption Characteristics in Some Calcareous Soils of North-West of Iran

آب و خاک

Article 3, Volume 25, Issue 5, November 2011   

Document Type: Research Article

DOI: 10.22067/jsw.v0i--.11205

Authors

G. Miraki^* ; A. Samadi

Department of Soil Science, Faculty of Agriculture, Urmia University

Abstract

Abstract
Phosphorus (P) sorption in soils is a key process governing the availability of P to crops. P sorption characteristics and their relationship to soil properties were determined in twenty-one paired surface soil samples (21 cultivated and 21 adjacent virgin soils) belonging to five soil types: Typic Calcixerepts, Typic Haploxerepts, Typic Endoaquepts, Vertic Endoaquepts, and Vertic Calcixerepts from sugar beet growing areas located in the north-west of Iran. After determining P adsorption isotherms, adsorption data was fitted to Langmuir and Freundlich equations to derive adsorption parameters. In comparison with Langmuir equation (R2 =0.82), Freundlich model provided a better description of P adsorption isothems (R2 =0.97) in both cultivated and adjacent virgin soils. Total P ranged from 1000 to 1398 and 1011 to 1394 mg kg-1, respectively. Continuous cultivation resulted in a considerable increase in available P (Olsen P) in cultivated soils. The amount sorbed P differed among soil types. The results showed that in all soils types except Typic Haploxerepts, equilibrium solution P concentration (EPC) was almost lower than the requirement for most crops (