The enhancement and improvement of soil fertility is one of the principal aims of or-ganic agriculture. The practical realization needs a multi-annual, complex approach as well as the economic valuation. Exemplarily, it is shown for the use of green chop with wide C/N ratio in field beans. The cost-benefits-analysis is done with results from field trials and data from real farms. It includes the yield effects on beans and the following grain. Additional impacts like weed suppression and nitrogen fixation are estimated, too. The results show that the gross margin difference for beans is averaged 27 to 55 €/ha (depending on application techniques), but for grains +176 €/ha. Overall, the farms can gain +1 to +13 €/ha in average by using green chop to improve soil fertility. A risk analysis regarding yield variability of beans and grains shows a surplus for farms in 70 to 75 % of cases
