Removal of fertilizer phosphorous by adsorption and precipitation processes is an important factor for yield loss in low input soils of arid and semi-arid regions. The phosphate sorption characteristics of surface and subsurface horizons of four semi-arid region soils and their relationships with soil chemical and physical properties were investigated. Two sorption sites were identified. The adsorption capacity was greater for region 1 while bonding energy was higher for region 2 sites. The adsorption maxima (b1) of the low concentration range (region-I) was 625-1250 Î¼g P/g and adsorption energy coefficient k1 ranged between 0.159-0.800 mL Î¼g-1. The calculated b and k values of high concentration range (region-II) were not treated as real adsorption parameters, because as the concentration increased, the data weakly confirmed Langmuir isotherm. This revealed the fact that Langmuir isotherm can be applied to phosphorous adsorption in soils and soil materials to a limited extent. Adsorption maximum of soils for P were found to be greater for soils and horizons high in CaCO3, clay and CEC. Statistically significant positive relationships were found between adsorption maximum and CaCO3, clay and CEC whereas important negative relationships were found between adsorption capacity and organic matter, sand, Fe2O3 and Al2O3 content of soils.
Ali Volkan Bilgili, Veli Uygur, Siyami Karaca, Orhan Dengiz and Salih Aydemir, 2008. Phosphorous Sorption in Some Great Soil Groups of Semi-Arid Region of Turkey
. International Journal of Soil Science, 3: 75-82.