Evaluation of Silicon Supplying Capacity of Paddy Soil by Silicon Liberation Dynamics Equation IThe Relationship between Parameter of Soil Silicon Liberation Dynamics Equation and Relative Yield

Twelve paddy soils with different pH values were selected to investigate the relationship between soil available Si,the accumulative liberation character of Si from soil and soil silicon supplying capacity.Field experiments,incubation experiments and chemical analysis were conducted.The results showed that: the classic 1mol L~(-1) HAc-NaAc buffer solution(pH=4) method was not adopted to evaluate the soil silicon supplying capacity of alkaline paddy soils because of the strong acidity.Under submerging conditions,the Si liberated from soil could be expressed by a one-order reaction dynamics equation y=kx~m.There was a significant linear correlation between the relative rice yield and accumulative amount of Si liberated in 120 days or the initial Si liberation velocity km.Therefore,the parameters in the soil silicon accumulative release equation could be used to evaluate the silicon supplying capacity of paddy soils with different pH values.