Effects on grassland productivity when converting from a conventional to an organic system

摘要

Well-established conventional grass fields on three different soil types were selected to determine the effect on forage yield when converting from a conventional system to an organic based system. Each field (block) was divided into 3 main plots, with different fertilizer treatments: (I) cattle slurry only (organic system), (II) cattle slurry + mineral fertilizer (conventional system) or (III) mineral fertilizer only (mineral system). The organic based system (I) was inferior to both the conventional (II) and the mineral (III) systems in terms of harvested dry matter and nutrient yield, nutrient content and nutrient use efficiency (NUE). It is concluded that organic systems during the first two years of conversion are less productive than conventional systems for grass-fed livestock under Icelandic conditions.