title: Phosphorus fractions in grassland soils.
abstract: The partitioning of P among major chemical forms was studied in 110 non-fertilized, semi-natural grassland soils of southeastern Sweden, comprising a wide range of soil acidity and other chemical properties. The P fractions bound to Ca and Fe were closely related to soil acidity, expressed as pH-KCl, especially when calculated as % of the total pool of mineral P. The relationship was inversely linear for log10P-Fe, whereas it was strongly positively curvilinear for log10P-Ca, with a sudden decrease of this fraction below pH-KCl 4.5. Phosphate bound to Al was inversely related to pH-KCl, but the variability accounted for was rather low. Easily exchangeable phosphate, interpreted as the most labile form of P-Al, was more closely related to soil acidity, with very low values at pHg-KCl > 5.5. Soil concentration of organic P was mainly a function of its contents of organic matter. Data were treated by PCA and stepwise regression analysis.
authors.affiliation: Department of Ecology, Lund University, Sweden. germund.tyler@planteco.lu.se
authors.forename: Germund
authors.initials: G
authors.lastname: Tyler
mesh_terms: D000535:Aluminum / Q000737:chemistry; D002118:Calcium / Q000737:chemistry; D017753:Ecosystem; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry; D009930:Organic Chemicals; D010758:Phosphorus / Q000737:chemistry*; D006109:Poaceae; D012044:Regression Analysis; D012987:Soil
chemical_list: D009930:Organic Chemicals; D012987:Soil; D010758:Phosphorus; D000535:Aluminum; D007501:Iron; D002118:Calcium