本文对两种不同起源水稻土在淹水条件下土壤有效硅的动态变化进行研究,以探索土壤中硅的供应状况。研究结果表明,淹水后土壤的有效硅均有不同程度的增长,四星期后趋于稳定,增长幅度基本相近。溧水县马肝土有效硅增加65～97ppm,兴化县粘土有效硅增加48～106ppm。试验还表明,土壤有效硅随氧化还原电位的下降而升高。其高峰为:兴化县土壤,Eh_7为正值(50～150mV)时出现;深水县土壤,Eh_7降至负值(—20～—40mV)时出现。施用绿肥则使土壤有效硅含量迅速提高。因此,土壤淹水和施用绿肥是提高土壤硅有效性的措施。 In this paper, the dynamic changes of soil available silicon in paddy soils under different waterlogging conditions were studied to explore the supply of silicon in soil. The results show that the effective silicon in soils after flooding all increased to some extent, stabilized after four weeks and the growth rates were similar. Lishui Ma liver soil effective silicon increased 65 ~ 97ppm, Xinghua clay effective silicon increased 48 ~ 106ppm. The experiment also showed that soil available silicon increased with decreasing redox potential. The peak appeared in the soil of Xinghua County, when Eh_7 was positive (50 ~ 150mV), soil appeared in Shaoxian County and Eh_7 was reduced to negative (-20 ~ -40mV). The application of green manure makes the soil available silicon content increased rapidly. Therefore, flooding of the soil and application of green manure are measures to improve the effectiveness of soil silicon.