Abstract: The experiment was conducted in Inner Mongolia Grassland Ecosystem Research Station.The stocking rate was 4.0 sheep/hm² within 1 hm² pasture fenced in 113 days(warm seasons).The resultsshowed that the amount of Sat the top of 0-30cm soil and in plant subsystem were 95.6% and 4% in thewhole grazing system,respectively.The soil was a great amount of Spool.The 93.7% of total S was accu-mulated in roots in the plant subsystem.The rate of S biological cycling was about 0.40 in the grazingsheep system.The amount of S through fences and urinary return was as 6 times as through litter decom-position,therefore grazing sheep speeded up S return,but no influence on S biological cycling rate was ob-served because the intake S by 4 sheep was only 0.4% of the whole graizing system.The input of S fromrainfall was 6.51kg/hm²/a in 1995,and S removal in animal products and in excretion which removed tocamping area was 0.63kg/hm² during warm season(113 days).The S status was positive balance about4.89kg/hm²/a for warm season pasture without considering leaching and other lost.

Key words: Inner Mongolia steppe, Sheep grazing system, Sulfur cycling

摘要： 通过对硫在各分室中的分布及其生物循环规律的研究。结果表明,95.6%的硫元素贮存于土壤中,是其主要的贮存库和流通枢纽,而植物中全硫含量只占整个放牧系统的4%左右,其中在植物亚系统中,93.7%的硫累积在根中。在硫的生物循环过程中,其循环速率为0.40,而绵羊通过粪尿归还的硫量是植物凋落物归还量的6倍,放牧加大了硫的归还量,但对硫的生物循环速率影响不大。在未考虑土壤淋落的情况下,该系统的输入校输出多4.89kg/hm²a,因此系统硫的平衡状况如何,则视土壤淋溶量而定,淋溶过程的研究将是物质循环和营养平衡状况的关键问题。

关键词: 内蒙古典型草原, 硫, 分布, 生物循环