AU - Samadi, A. AU - Sepehr, E. TI - Use of Phosphorus Adsorption Isotherms for Determining Fertilizer Requirement of Wheat PT - JOURNAL ARTICLE TA - JSTNAR JN - JSTNAR VO - 17 VI - 65 IP - 65 4099 - http://jstnar.iut.ac.ir/article-1-1345-en.html 4100 - http://jstnar.iut.ac.ir/article-1-1345-en.pdf SO - JSTNAR 65 ABĀ  - 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 ( CP - IRAN IN - Soil Science Department, Urmia University, Urmia, I.R. Iran LG - eng PB - JSTNAR PG - 173 PT - Research YR - 2013