Increasingly strict legislation about fertilizer inputs and developing organic regulations are a strong
stimulation to optimize the internal nutrient dynamics of organic arable farms. In the project
“PlantyOrganic” , initialized by Biowad and realized at SPNA location Kollumerwaard, a challenging
arable system is developed and tested: 100% internal nitrogen supply without input of nutrients from
outside. In this report the design of the rotation and fertilizer scheme is presented and discussed, and
the starting conditions in spring 2012 are documented. The NDICEA nitrogen model is used to
explore the nitrogen dynamics. It is concluded that a 100% farm-own nitrogen supply can be
achieved with good production levels. The 2012 results gave no reason to reconsider the rotation
and fertilizer design, but since this was the first year of this experiment none of the crops had the precrop
as foreseen in the design and the fertilizer used was only partly cut-and-carry fertilizer
