In China the paddy yield per unit area varies from 4-5 times between the lowest and the highest.In order to low-yield paddy soils,protinote their fertility and increase the rice yield,it is primarily necessary to work out a proper drainage project in paddy Field.end to lower,the ground water table so as to fundamentally improve the aeration condition in the root-layer of paddy soil.The higher rnntrnt of organic matter in paddy soil is related to the poor water regiame,hawing nothing to do avith the fertility level.The effect of soil organic matter on the iinprovetrient of physical properties of paddy soil is conditional.For the clayey soils of,low-yield and those located in lowland,only by ameliorating their poor water regime can the organic matter be brought into full play.For the well-drained paddy soils,the effect of organic matter on physical properties of the soil is remarkable.