Back An organic or mineral product incorporated into the soil to maintain or increase its fertility. The use of green manure (plants grown in the vineyard that are ploughed in rather than mowed) and other composted organic fertilisers, often based on manure and sold in bags, is not disputed. On the other hand, chemical mineral fertilisers, which have been overused in the past, are dangerous for the biological balance and the environment and can harm the quality of wines. Only soil analyses can detect deficiencies, which will then be corrected accordingly.