(4) Decomposing green legume plants Explanation: Green undecomposed material used as manure is called green manure. It is obtained in two ways: (1) growing green manure crops usually belonging to leguminous family and incorporating into the soil after sufficient growth or (2) by collecting green leaf from plants grown in wastelands, field bonds and forest. The most important green manure crops are sunnhemp, dhaincha,. etc.