Phosphorus adsorption evaluation for fertilizer recommendation on three calcareous soils of Karaj region, Iran
Subject Areas : Agroecology Journal
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Abstract :
The variability of phosphorus concentration in soil solution as adsorption point of view by different minerals could be use for phosphorus recommendation. Identity of phosphorus adsorption on mineral surfaces could be studied by different equations, which their suitability depends on the soil characteristics and the aim of research. But the main concept is based on to equilibrate the soils with electrolyte solution containing different phosphorus concentration in a distinct time and temperature. In this study, three calcareous soil samples (with 7, 14 and 21 percentages CaCO3), fine grinded (<1mm diameter) were equilibrated with five concatenations (0, 12.5, 25, 50 and 75 µgrP/ml) which prepared from K2H2PO4 in 0.01 molar CaCl2. The linear types of Froundlich and Longmuir equations were fitted with high probability (p<0.01) and were used for interpretation phenomena by three soils. The Froundlich equation had higher correlation coefficient. The maximum adsorption values (b) of Longmuir equation for Karaj, Kordamir and Aderan soil series were 65.74, 74.2 and 75. 2, and the energy constant (k) were 2.95, 3.49 and 0.43, respectively. The samples were linear to concentration value (C) as high as 0.75, 0.73 and 0.29 mg/l for Karaj, Kordami, and Aderan soil series, respectively.
