To understand the characteristics of soil dissolved organic carbon(DOC),dissolved organic nitrogen(DON)and inorganic nitrogen(Nmin)responding to different green manures used as summer catch crops,six species of green manures were chosen in this study.These species belong to three families of Leguminosae(Mung bean,Sesbania,India cowpea),Gramineae(Sweet corn,Gaodan grass)and Amaranthaceae (Amaranth),respectively.A control treatment without green manure was included.Green manures were returned into soil in two ways,ie,all biomass returned and only the roots returned.The soils were sampled in 0～100 cm soil profiles at an interval of 20 cm on 1 d before and on 20 d after the green manures returned.The results showed that,the soil DOC contents increased after planting green manures,especially in 0～40 cm layer.Planting green manures reduced the soil DON and the Nmin contents.When all biomass returned into the soils,the DOC contents in the whole soil profile were increased in all green manure treatments,and the treatments of Leguminosae and Gramineae enhanced more than the treatment of Amaranthaceae did.Turning over the green manures could increase the soil DON and Nmin contents as well,especially in the treatments of all biomass returned.The soil DON and Nmin contents varied among different treatments with the trend of Leguminosae treatments