TY - JOUR ID - 55936 TI - The effect of organic matter removal on desorption and retention characteristics of phosphorus in some calcareous soils JO - Iranian Journal of Soil and Water Research JA - IJSWR LA - en SN - 2008-479X AU - Mahdizadeh, Masumeh AU - Reyhanitabar, Adel AU - Oustan, Shahin AU - Heidari, Saber AD - Former Graduate Student, Soil Sci. Dept., Faculty of Agric., Univ. of Tabriz, Iran AD - Assosiate Prof., Soil Sci. Dept., Faculty of Agric., Univ. of Tabriz, Iran AD - Assoc. Prof., Soil Sci. Dept., Faculty of Agric., Univ. of Tabriz, Iran AD - Ph.D. Student, Soil Sci. Dept., Faculty of Agric., Univ. of Tabriz, Iran Y1 - 2015 PY - 2015 VL - 46 IS - 2 SP - 315 EP - 330 KW - Desorption KW - isotherm KW - organic matter KW - Phosphorus KW - Sodium hypochlorite DO - 10.22059/ijswr.2015.55936 N2 - The effect of organic matter removal on retention and desorption characteristics of phosphorus (P) was studied in 12 calcareous soils. Soil organic matter was removed through an application of sodium hypochlorite (NaOCl) solution at room temperature. To evaluate the characteristics related to P release, desorption experiments following adsorption ones were performed at the highest initial concentration of phosphorus (100 mg P L-1). The results revealed that the amount of P desorption decreased following a removal of organic matter. P retention data were adequately described through Freundlich, Langmuir, Temkin, Gunary and Dubinin Radushkevich equations, but the most appropriate model was found to be the Langmuir Equation. Phosphorous retention maxima,b, calculated from Langmuir equation after soil organic matter removal ranged from 392.1 to 757.5 with a mean value of 560.8 mg/kg,which showed an increase of 7.4 % over the previously soil organic matter removal. Phosphorus retention and sorption isotherm showed hysteresis which indicates retention and desorption mechanisms not being the same. The mean hysteresis indices calculated from Freundlich decreased from 29.7 to 18.1 % after a removal of organic matter. Also, after organic matter removal, maximum P retention (qm) calculated from Dubinin Radushkevich equation increased by 8.6 %. The energy of P retention calculated from Dubinin Radushkevich model was 19 and 25 kJ mol-1, before and after organic matter removal, respectively, which, according to this equation, represents the chemical retention mechanism of P in the studied soils. The P standatd requirement, P0.2, a measure of the P fertilizer reqired for optimal production, increased more than twice following soil organic matter removal. UR - https://ijswr.ut.ac.ir/article_55936.html L1 - https://ijswr.ut.ac.ir/article_55936_9e450422d7f5db6889affc4aff690d47.pdf ER -