本试验是基于五年长期定位施硫土壤,通过测定五年秋收后土壤有效硫含量和pH,得到土壤有效硫和pH的年际间变化规律；通过测定第五年玉米各重要生育时期土壤有效硫含量和pH,得到玉米完整生育期内土壤有效硫和pH的变化规律。结果表明,高浓度硫肥的土壤有效硫含量逐年递增,第三年开始,增长趋势趋于平缓,到第五年基本持平,低浓度硫肥处理始终呈上升趋势；在玉米生育期内,各处理土壤有效硫含量变化趋势呈现出,灌浆期之前降低速率较快,后期变缓；低浓度硫肥处理的土壤pH会通过土壤的缓冲性调节,呈现出动态平衡趋势,而高浓度硫肥处理的土壤pH则会随着施硫年份逐渐降低,但下降趋势从第四年开始逐渐变缓；在玉米生长前期,高浓度处理会出现pH降低的现象,而在吐丝期出现上升趋势,灌浆期达到最大值,而低浓度硫肥处理的pH受影响较小,处于动态平衡状态。

This experiment is based on long-term sulfur application in soil for five years. By measuring the soil available sulfur content and pH after five years of autumn harvest, the interannual variation patterns of soil available sulfur and pH were obtained; By measuring the soil available sulfur content and pH during each important growth period of corn in the fifth year, the changes in soil available sulfur and pH during the complete growth period of corn were obtained. The results showed that the effective sulfur content in soil treated with high concentration sulfur fertilizer increased year by year. Starting from the third year, the growth trend tended to be gentle, and remained basically unchanged by the fifth year. The treatment with low concentration sulfur fertilizer consistently showed an upward trend; During the growth period of corn, the trend of soil available sulfur content in each treatment showed a rapid decrease before the filling period and a slower decrease in the later stage; The soil pH of low concentration sulfur fertilizer treatment will show a dynamic equilibrium trend through soil buffering regulation, while the soil pH of high concentration sulfur fertilizer treatment will gradually decrease with the year of sulfur application, but the downward trend will gradually slow down from the fourth year onwards; In the early stage of corn growth, high concentration treatment will lead to a decrease in pH, while an upward trend will occur during the silking stage and reach the maximum value during the filling stage. However, the pH of low concentration sulfur fertilizer treatment is less affected and in a dynamic equilibrium state.