Research Station Agroscope Reckenholz-Tänikon ART, CH-8046 Zurich

Determination of nitrogen fertilization standards for arable crops

This paper explains the principle of economically optimal N-fertilisation (Nopt). This principle allows the quantitative derivation of N-fertilisation standards based on N-fertilisation trials. The optimum level of N-fertilisation thus found represents a good compromise between the economic and ecological aims of arable farming. Within the framework of the ‘Principles of Fertilisation in Arable and Forage-Crop Production’ (GRUDAF) 2009 studies, the Nopt for several important arable crops was determined based on extensive N- fertilisation trials. For all crops but maize, the results of these studies have led to an increase in optimum N-fertilisation by 10 to 40 kg N ha-1. In order to promote N-fertilisation adapted to site productivity, however, the N- fertilisation standards of these crops were not as a rule raised, but rather yield-dependent correction factors were introduced for the N-quantities to be applied.

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