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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2014

2013

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Sammendrag

Nitrogen (N) efficiency on farm gate is studied for the year 2010 on ten Norwegian, organic dairy farms and ten conventional as references. Preliminary results are presented here, and the method is discussed. N-efficiency is calculated as Net N-Export (kg) / Net N-Import (kg). Nitrogen from biological N-fixation had a large impact on calculated N-efficiency. Because of large annual variations and uncertain estimates of amount of N from biological N-fixation caused by uncertainties in roughage yields, clover content and the amount of nitrogen fixed per kg clover harvested, the numeric values of estimated N-efficiency should not be taken as exact values. N-efficiency is estimated with and without biological N fixation. There are large variations in farm size, use of concentrates and milk yield per cow within the group of organic farms. However, the variation is even larger within the conventional farms. On average, the estimated N-efficiency was higher on the organic than on the conventional farms. However, there are large variations in estimated N-efficiency within the organic as well as the conventional group. This gives us the possibility to identify on which farms actions should be taken to improve N-efficiency.