研究了不放牧、轻度放牧(1.13羊·hm-2)和重度放牧(1.95羊·hm-2)3个牧压下天山北坡草原化荒漠草地植物粗蛋白、粗脂肪、土壤容重和有机质含量的变化。结果表明:1)春季和秋季放牧后, 不放牧草地的植物粗蛋白和粗脂肪含量均下降。春季放牧后, 轻度和重度放牧处理的植物粗蛋白和粗脂肪含量均比春季放牧前略高, 而秋季放牧后粗蛋白和粗脂肪含量均低于秋季放牧前;2)春季和秋季放牧前后, 土壤容重变化均不大;春季重度放牧处理后, 土壤有机质含量表现出下降趋势, 且与不放牧和轻度放牧处理间差异极显著(P<0.01)。秋季放牧后, 轻度和重度放牧处理各层土壤有机质含量与秋季放牧前相比略有降低。3)从植物粗蛋白和粗脂肪含量, 土壤容重和有机质含量变化来看, 1.13羊·hm-2轻度放牧处理是较为合理的放牧强度。
This study investigated the changes of crude protein and crude fat, soil bulk density and soil organic matter under different grazing pressures in steppe desert grassland of northern Tianshan Mountains. The results showed: 1) for 0 sheep·ha-1 treatment, plant crude protein and crude fat decreased after grazing season compared to the beginning of grazing season in spring and autumn. Consistent with this, a similar trend was observed in autumn season for 1.13 and 1.95 sheep·ha-1 treatment; however, in spring season, the crude protein and crude fat increased after grazing in spring for 1.13 and 1.95 sheep·ha-1 treatment. 2) soil bulk density are relative stable for all treatments before and after grazing season; soil organic matter showed a down trend after spring grazing for 1.95 sheep·ha-1, and a slight decrease was observed in terms of each soil layer organic matter for 1.13 and 1.95 sheep·ha-1 after autumn grazing. There was a significant difference between 1.95 and 0 and 1.13 sheep·ha-1 in terms of soil organic matter after spring grazing(P〈0.01). 3) From the change of crude protein and crude fat contents, soil bulk density and soil organic matter content, 1.13 sheep·ha-1 is more reasonable grazing intensity.