摘要
年际内短期放牧是青藏高原东北边缘地区草地利用的主要方式,而土壤有机碳和全氮含量是草地生产力维持的基石。以青藏高原东北边缘天祝县高寒草甸土壤为对象,研究了不放牧(对照)、轻度放牧(0.8头牦牛/hm2)、中度放牧(1.0头牦牛/hm2)和重度放牧(1.2头牦牛/hm2)条件下土壤有机碳和全氮以及土壤微生物量碳氮含量的变化特征。结果表明:重度放牧使土壤表层0～10cm和10～20cm全氮含量降低了12.5%和10.7%,中度放牧使10～20cm土层土壤有机碳含量增加了11.21%,其他各层全氮和有机碳含量并未随放牧强度变化发生显著变化;微生物量氮在0～10cm土层随放牧处理变化十分明显,轻度放牧、中度放牧和重度放牧下比对照分别增加了65.35%、25.23%、46.91%(P<0.05),而0～10cm土层微生物量碳在中度放牧处理下含量比对照显著增加(P<0.05),说明在表层相对于土壤碳氮,微生物量碳氮对短期放牧的反应更为灵敏。
Annual short term grazing is the main grassland utilization activity in the north eastern edge of the Qinghai-Tibetan Plateau. The status of soil nutrients is highly related to the maintenance of grassland productivity. In this study, the change characteristics of soil organic carbon （SOC）, total nitrogen （TN）, microbial biomass carbon （MBC） and microbial biomass nitrogen （MBN） were studied in an alpine meadow in the north eastern edge of Qinghai-Tibetan Plateau under control experiment （CK）, light graz ing （0.8Yaks / hm^2 LG）, moderate grazing （1.0Yak / hm^2 MG） and heavy grazing （1.2yaks/hm^2 HG）. TN content in the 0-10cm and 10-20cm soil layer under HG was significantly reduced by 12.5G and 10.7% respectively compared with those under the control. SOC in the 10-20cm soil layer under MG was increased significantly by 11.21G than that under the control. MBN in the 0-10cm soil layer under I.G, MG and HG was respectively increased by 65.35%, 25.23% and 46.91% than th ose under the control （P 〈0.05）. MBC in the 0-10cm layer under MG significantly was increased by 51. SG than that under con trol （P〈0.05）. It was concluded that MBN and MBC are more sensitive thanTN and SOCin surface soil after short-term grazing in the region.
出处
《中国草地学报》
CSCD
北大核心
2013年第1期55-60,66,共7页
Chinese Journal of Grassland
基金
国家农业行业公益科技项目(200903060
201203006)资助
关键词
高寒草甸
放牧强度
土壤有机碳
土壤全氮
土壤微生物量
Alpine meadow
Grazing intensity
Soil organic matter
Total soil nitrogen
Soil microbial biomass
