TY - JOUR T1 - Use of Phosphorus Adsorption Isotherms for Determining Fertilizer Requirement of Wheat TT - استفاده از هم دماهای جذب فسفر در تعیین نیاز کودی غلات JF - JSTNAR JO - JSTNAR VL - 17 IS - 65 UR - http://jstnar.iut.ac.ir/article-1-1345-en.html Y1 - 2013 SP - 173 EP - 184 KW - Fertilizer phosphate requirement KW - Adsorption isotherms KW - Soil test KW - Freundlich equation KW - Langmuir equation. N2 - In order to determine optimum equilibrium solution phosphorus (P) concentration using P adsorption isotherm and obtain model(s) by integrating soil solution P concentration, physicochemical properties, and soil P test (available P) which predict standard P requirements to achieve maximum yield, laboratory and glasshouse experiments were conducted on 36 soil samples belonging to 15 soil series and 14 soil samples, respectively. Using wheat as a test crop, the glasshouse experiment was laid out with five P levels in a completely randomized design with three replications. Concentrations of P in solution established by adding P in the pots estimated from the sorption curve ranged from 0.2 to 1.2 mg P/L including check treatment (no P). The results showed that equilibrium solution P concentration (EPC) was almost low in comparison with the requirement for most crops ( M3 ER -