Availability of phophorus in intensive used grassland soils
Keller, A.(Agroscope FAL Reckenholz, Eidgenoessische Forschungsanstalt fuer Agraroekologie und Landbau, Zuerich (Switzerland)) | Van der Zee, S.
We investigated the sorption capacity and availability of phosphorus (P) in soils of the Lippenrütibach catchment (Canton Luzern, Switzerland) to assess the risk of P-losses from agricultural land in the long-term. The different available P-forms in soil were characterised using six P extraction methods. The soils in the study area revealed a high P-sorption capacity and medium to high P-contents. In the top 5 cm soil layer these were a few times larger than in the soil layer 5 to 20 cm. The P-saturation index, expressed as the ratio between P-content and P-sorption capacity in soil, was on average 0.48 (0 to 5 cm) and 0.36 (5 to 20 cm) and was closely related to both the soluble P and plant available P in soil. The P-saturation index varied strongly between sites of different farms as well as between sites of the same farm. Based on the P-sorption capacity and the P-saturation of the soils investigated, we presume that a reduced P-fertilization below the P-demand of the plants may decrease the potential risk of P-losses in the catchment only slowly, i.e. within 10 to 20 years.
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Эту запись предоставил Agroscope Reckenholz-Tänikon Research Station