Effect of salicylic acid on phosphorus sorption characteristics in a calcareous soil

Sepehr, Ebrahim; Mousavi, Roghiyeh

doi:10.22059/ijswr.2013.50218

Effect of salicylic acid on phosphorus sorption characteristics in a calcareous soil

Document Type : Research Paper

Authors

Ebrahim Sepehr ¹
Roghiyeh Mousavi ²

¹ Assistance Prof., Faculty of Agriculture, University of Urmia, Urmia, Iran

² MSc. Student, Department of soil science, Faculty of Agriculture, University of Urmia, Urmia, Iran

10.22059/ijswr.2013.50218

Abstract

Salicylic acid is an important organic acid in plants rhizosphere soil exuded in the phosphorus (P) deficiency condition. To study the sorption behavior of P in the presence of salicylic acid, a batch experiment was conducted with different concentrations of salicylic acid (0, 2, 5 and 10mM) and P (0- 45 mg P/L) in a calcareous soil. The results showed that application salicylic acid decreased the sorption of phosphate due to competition with organic acid for the sorption sites. The maximum phosphorus sorption (q_max) decreased by increasing salicylic acid concentration from 326 to 246 mg/kg. The application salicylic acid decreased all sorption parameters such as Langmuir binding strength (K_L) (from 0.20 to 0.14 ml/g), sorption capacity of Freundlich (K_f) (from 59 to 46 mg/kg), the slope of Temkin equation (K_T) (from 62 to 46) and the intercept of Temkin equation (A) (from 59 to 52 mg/kg). The standard phosphorus requirement (SPR) in equilibrium concentration 0.3 mg P/L calculated by Langmuir (SPR_L), Freundlich (SPR_F) and Temkin (SPR_T) equations significantly decreased, for example SPR_F decreased from 31.5 to 24.7 mg P/kg. Eventually it can be said, application salicylic acid and /or plants genetic improvement for more exudation this acid cause to increase P availability and reduce fertilizer requirement.

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