Southern Brazil is carachterized by soil classes with contrasting mineralogical composition and chemical behavior that directly affect the P adsortion capacity. This study is a first detailed regional assessment of the main factors (including mineralogical composition, total organic C, and specific surface area) that determine P adsorption in 60 representative soils of southern Brazil under natural vegetation. Most soils showed medium to clay texture. Organic C increased with increasing altitude and rainfall but decreasing temperature. Kaolinite, goethite and hematite were the dominant minerals in the highly weathered soils (Ferralsols and Nitisols), associated with smaller amounts of 2:1 clay minerals, quartz and gibbsite. In soils with a textural gradient (Acrisols, Alisols and one Plinthosol), minerals in the clay fraction consisted of kaolinite and quartz together with lower proportions of Fe oxides, 2:1 clay minerals and mica. The less weathered soils (Cambisols, Chernozems, Vertisols and Luvisols) abounded with kaolinite and 2:1 clay minerals in addition to goethite, ferrihydrite and quartz. P adsorption was positively correlated with clay and organic C content and specific soil surface area. The mineral most strongly influencing P adsorption was gothite, and hematite and gibbsite to a lesser extent.

巴西南部地区的土壤种类繁多，其矿物成分和化学行为形成鲜明对比，直接影响P的吸附能力。这项研究是对主要因素（包括矿物组成，总有机碳和比表面积）进行的首次详细区域评估，这些因素决定了巴西南部自然植被下60种代表性土壤中磷的吸收。大多数土壤显示中等至粘土质地。有机碳随海拔高度和降雨的增加而增加，但温度降低。高岭土，针铁矿和赤铁矿是高风化土壤中的主要矿物质（铁铝土和尼古斯土），与少量的2：1粘土矿物质，石英和三水铝石有关。在具有质地梯度的土壤中（尖锐粉尘，Alisols和一种Plinthosol），粘土级分中的矿物包括高岭石和石英以及较低比例的铁氧化物，2：1粘土矿物和云母。风化较弱的土壤（坎贝索尔，黑钙土，Vertisols和Luvisols）除了针铁矿，三水铁矿和石英外，还富含高岭石和2：1粘土矿物。磷的吸附与粘土和有机碳含量以及土壤比表面积呈正相关。影响P吸附最强的矿物是针铁矿，而赤铁矿和菱镁矿的程度较小。磷的吸附与粘土和有机碳含量以及土壤比表面积呈正相关。影响P吸附最强的矿物是针铁矿，而赤铁矿和菱镁矿的程度较小。磷的吸附与粘土和有机碳含量以及土壤比表面积呈正相关。影响P吸附最强的矿物是针铁矿，而赤铁矿和菱镁矿的程度较小。