稻作制与有机肥及地下水位对水稻土硫素状况的影响Ⅰ.全硫和有效硫含量

为探明耕作、施肥、灌溉等农艺措施对水稻土硫素状况的影响，研究了在长期定位试验条件下稻作制、有机肥用量及地下水位对水稻土全硫及有效硫含量的影响.结果表明，不同稻作制间，耕层土壤全硫含量以稻-稻-冬泡最高，稻-稻-冬绿次之，稻-稻-冬油最低；有效硫含量则以冬绿处理最高，冬泡处理最低；不同有机肥施用水平之间，耕层土壤全硫含量为常量有机肥处理最高，高量有机肥处理居中，化肥处理最低.高地下水位能提高土壤中全硫含量，但不利于土壤硫的有效化.

Effects of Rice-Based Cropping System, Organic Manure and Ground Water Level on Sulphur Status in Paddy Soil Ⅰ.Total S and Available S Contents

A long-term stationary experiment was carried out to study the effect of rice-based cropping system ,organic manure and ground water level on soil sulphur. Among 3 rice-based cropping systems,the total S contents of plough layer in the treatment of rice-rice flooded fallow in winter were the highest;those in the treatment of rice-rice-green manure came the second;those in the treatment of rice-rice-rape were the lowest. Available S contents of plough layer in the treatment of rice-rice-green manure in winter were the highest;those in the treatment of rice-rice-flooded fallow were the lowest;those in the treatment of rice-rice-rape were the middle. Among 3 applications of organic manure,the total S contents in the treatment of normal rate applying of organic manure were higher than those in the treatment of high rate applying of organic manure,while in the treatment of inorganic fertilizer,the total S contents were the lowest. Higher ground water level can increase the total S contents in soil,but lower the minerilization of organic S.