Alfalfa (Medicago sativa L.) belongs to the significant part of legume pastures and is high-quality forage. In organic farming, it plays a pivotal role in contribution to a soil nitrogen balance. The aim of this study was to evaluate the effect of the site and the time on the root diameter, number of nodules and yield of alfalfa in field experiments of organic farming. On six areas with different soil texture (clay content: 12-32%) in south Bavaria, Germany, plants were sampled with the monolith method. In May, July and August 2011 the yield, the root diameter and the number of nodules were evaluated. The yield amounted to 8-12 t ha-1. The root diameter increased, the number of nodules decreased with time. The significant differences were investigated in site and in time as well. The nutrients and the other site parameters will be focused yet
