Stickstoffflüsse auf der Weide bei Vollweidehaltung im alpinen Raum Österreichs

Summary

The aim of this investigation was to evaluate the dung distribution and the N-balance on the pasture in a seasonal grass-based system in organic farming. This investiga-tion was carried out on the research farm (680 m altitude, 1000 mm precipitation hereof 600 mm during 200 days vegetation period, 6.5 °C average temperature, 34 ha grassland hereof 10 ha pasture areas, 14 brown swiss dairy cows 610 kg live weight and 14 holstein frisian 540 kg live weight) of the Institute for Organic Farming (HBLFA Raumberg-Gumpenstein) in the alpine area of Austria. Two pasture areas (former mowing pasture and permanent grassland), Beifeld (2 ha, plant up to sloped) and Stallfeld (1.8 ha, steady sloped), were exemplarily used to show the dung distribution and the calculated N-balance. The dung distribution on the Stallfeld was more homo-geneous as on the Beifeld. A very high N removal was discovered on both areas. The accumulation (calculated 100-140 kg N ha-1) of N was much lower than the removal (calculated 210-240 kg N ha-1). One consequences of this high N removal was an increase of white clover (2005 12% and 2006 29% by weight), a legume which re-ceives the N via fixation. The long term impacts on the grassland diversity could not responded by one research year and further investigations are necessary.