Evaluation of Nitrogen Utilization By Means of the Concept of Primary Production Balance

Pentti Seuri and Helena Kahiluoto

Abstract
Primary production balance (PPB) indicates the ratio (*) between harvested nutrients and nutrients put into crop production from outside the system (=primary nutrients). The PPB is independent of the final output (crop vs. animal products) and can be used to evaluate different systems (farms).

The utilization of nitrogen (N) was evaluated by means of the PPB on nine organic farms, stockless and mixed ones, in eastern Finland. The mixed farms were able to reach a remarkably higher primary production balance (1.0 – 1.2) compared with the stockless ones (0.5). Values higher than 1.0 indicate recirculation of nutrients.

Other components of the high PPB were legumes as nitrogen source and optimum livestock density.


Source
Köpke et al (Eds) (2005): Researching Sustainable Systems. Proceedings of the First Scientific Conference of the International Society of Organic Agriculture Research (ISOFAR). ISOFAR / IOL / FiBL, Bonn and Frick; ISBN 3-906081-76-1


Author Locations and Affiliations
MTT Agrifood Research Finland, Huttulantie 1, FI-51900 Juva, Finland, Tel. +358 15 321230, E-Mails: pentti.seuri@mtt.fi, helena.kahiluoto@mtt.fi Website: www.mtt.fi


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