Forms of phosphorus in sediments eroded from burnt soils

Wildland fires can increase erosion and nutrient loss in runoff by loss of vegetative cover and changes in soil structure and chemical composition. Thus, we investigated the effect of vegetation burning intensity on the loss of particulate P forms in eroded sediments by using a sequential fractionation method that distinguishes organic and inorganic P forms of different lability. Moderate burns, while not affecting P form distribution in the soil, led to high levels of inorganic P (largely Bic-Pi, NaOH-Pi, and HCI-P) in eroded sediments, with phosphorus enrichment ratios ranging from 3.36 to 5.04. Severe burns modified P form distribution in the soil, and led to the almost complete disappearance of extractable organic P from the soil [...]