Phosphorus fractions in soils from an area with high density of livestock population

The concentrations of total phosphorus and its distribution in fractions of different solubility have been investigated in 6 different organic manures and in 69 soil samples from two counties with high concentrations of livestock population (Cloppenburg and Vechta, Lower Saxony). In the manures, large proportions of total P (means: 24% and 44%) were extracted by H 2 O and anion exchange resin so that increases in labile soil P fractions can be expected if these manures are applied. The high total P‐concentrations of the soils up to 8173 mg kg −1 were related to pedogenesis and soil use. Data such as soil P test (H 2 O‐P, DL‐P) values above the P‐fertilizer recommendations and considerably larger proportions of soluble and labile P‐fractions (7%‐47% of total soil P) than in other regions strongly suggested that significant P‐losses from the soils are likely. Therefore, reductions of P inputs to soils and measures to reduce the P‐solubility and mobility are necessary for water conservation in this region.