Abstract: Field experiments of rape-rice rotation cropping on paddy soils developed from loess parent material in hilly regions between Yangtze and Huaihe rivers indicated that during the period of rape growth, soil sulphur in plough layer mainly came from substratum, and then, from atmospheric deposition.The output of sulphur was mainly resulted from the absorption by rape, and next, from leaching by raining.The amount of sulphur input in plough layer was less than that of its output during the period of rape growth and the sulphur pool in plough layer was reduced by 8.76 kg·hm^-2, 22% of which was resulted from the decrease of inorganic sulphur pool.During rice growing, the sulphur input in plough layer mainly came from irrigation, and then, from the supply of substratum and atmospheric deposition.The output was resulted mainly from leaching, and next, from absorption by rice, The sulphur input in plough layer was more than its output, and the sulphur pool in top soil layer was increased by 18.69kg·hm^-2, 18% of which was resulted from the increase of inorganic sulphur pool.Therefore, the amount of sulphur imput in plough layer was more than that of its output during the whole rape-rice rotation, and the sulphur pool in plough layer was increased by 9.93kg·hm^-2, 13% of which was from the increase of inorganic sulphur pool.

Key words: Sulphur in soil, Sulphur cycle, Rotation, Hills, boreal forest, human-caused fire, spatial point pattern analysis, climate change, Great Xing’an Mountains