The effects of soil and water conservation (SWC) on soil properties are well documented.However,definitive and quantitative information of SWC and its interactions with soil properties on soil productivity is lacking for hilly red soil region of southern China.Experiments were conducted in the hilly red soil region of southern China for seven years in three runoff plots,each of which represented different SWC forest-grass measures.Principal component analysis and multiple regression techniques were used to relate the aboveground biomass (representing soil productivity) to soil properties.Based on the final regression equations,soil organic carbon content (Soc) is significantly correlated with soil productivity under the condition of forest-grass measures,whereas pH value and cation exchange capacity (Cec) are the main factors for soil productivity without SWC.Therefore,SWC plays an important role in sequestering Soc and improving soil productivity.