Phosphate and nitrate sorption on calcareous soils from Spain

Abstract

The sorption processes of phosphate and nitrate on calcareous soils from Almería (East‐Andalucía, Spain), and from aqueous solution at 30°C, have been studied. The experimental data for phosphate and nitrate sorption on the soils studied were compared by using the Langmuir's equation. Sorption capacity values (X_m) range from 1.38 × 10^‐3 mmol H₂PO₄ ^‐ g^‐1 volcanic soil to 11.88 mmol H₂PO^‐ ₄ g^‐1 brown lime and saline soils for phosphate, and from 0.19 × 10^‐3 mmol NO^‐ ₄ g^‐1 desert soil to 0.34 × 10^‐3 mmol NO₃ ^‐ g^‐1 brown lime soil for nitrate. X _m values were higher for phosphate than for nitrate. The sorption of phosphate and nitrate on Almería soils at the experimental conditions used was correlated with the soil organic matter content. The correlation coefficients were 0.77 for phosphate and 0.95 for nitrate.

Key words:

• nitrate
• phosphate
• sorption
• semiarid hot region