To understand the influence of organic manures composted with the wheat straws, oilcakes and cottonseed cakes, and chemical fertilizers on soil organic carbon and soil productivity, a long-term plot experiment was established in a calcareous fluvo-aquic soil (aquic inceptisol) in Fengqiu county, Henan province, China in September 1989 and was used to monitor soil respiration during the maize and wheat growth seasons from June 2002 to June 2003. The study involved 7 treatments: organic manure (OM), half orga...