%A Christine Bosshard %A Peter Sorensen %A Emmanuel Frossard %A Jochen Mayer %A Paul M?der %A Simone Nanzer %A Astrid Oberson %T Stickstoffausnutzungseffizienz von 15N-markierter Schafsg?lle und 15N-markiertem Minerald?nger in biologisch und konventionell bewirtschafteten Anbausystemen %X Nitrogen (N) utilisation by crops has to be improved to minimize losses to the environment. We investigated N use efficiency of animal manure and mineral fertiliser and fate of fertiliser N not taken up by crops in a bio-organic (BIOORG) and a conventional (CONMIN) cropping system of a long-term experiment over three vegetation periods (wheat-soybean-maize). Microplots received a single application of 15N-labelled slurries or mineral fertiliser. At the end of each vegetation period we tested whether higher microbial activity and biomass in BIOORG than CONMIN soils and lower long-term N input level in BIOORG affected use efficiency and fate of fertiliser N not taken up by crops. In total 41%, 15% and 50% of 15N applied as urine, faeces and mineral fertiliser was recovered by the three crops. 15N recovered from originally applied urine, faeces and mineral fertiliser in the topsoil at the end of the third vegetation period was 19%, 25% and 20%, respectively. Of urine-, faeces- and mineral fertiliser-15N 40%, 61% and 29% was not recovered by the three crops and in topsoil suggesting significant transport of 15N-labelled components to deeper soil layers. BIOORG and CONMIN differed neither in fertiliser N use efficiency by crops nor in 15N recovery in soil indicating insignificant differences in turnover and utilization of applied manure N in the bio-organic and conventional cropping system. %D 2009 %K 15N, DOK-Versuch, Mikroparzellen, Stickstoffausnutzungseffizienz %L orgprints14392