The use of legume crops as a green manure is considered an important agronomic technique in cropping systems to improve soil quality and crop production. We conducted a field experiment to evaluate the impact of legume crops Grasspea (Lathyrus sativus), Vetch (Vicia villosa L), Berseem clover (Trifolium alexandrinum), Sainfoin (Onobrychis sativus), Maragheh Vetch (Vicia dasycarpa) and Control treatment (without green manure) on the organic carbon (OC), calcium carbonate equivalent (CCE), bulk density, moisture percentage and electrical conductivity of soil extract. This study was carried out at the Research Farm of Maragheh University, Maragheh, Iran in 2013. Legume crops were sown at the beginning of May and ploughed three months later. Soil samples were taken in autumn before wheat sowing (September). Result showed that the green manure application have significant effects on the organic carbon (OC), calcium carbonate equivalent (CCE), bulk density, moisture percentage and electrical conductivity of soil extract. The highest organic carbon was obtained with the application of grasspea treatment. The bulk density content was significantly higher in control soil than in legume crop treatments, while the electrical conductivity of soil behaved in the opposite way. Significantly higher calcium carbonate equivalent was observed in the vetch, and berseem clover crops than control. Also the highest value of moisture content was observed with vetch application. Therefore, cultivation of legume crops for so-called green manure can be useful management practice for enhancing soil properties.
