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

The concentration of total phosphorus and its distribution in fractions of different solubility have been investigated in 6 different 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 H2O 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 (H2O-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, reduction of 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.