放牧模式对祁连山东缘高寒草甸土壤理化特性和物种多样性的影响

Effects of grazing modes on soil physical,chemicalproperties and species diversity in alpine meadowin the eastern margin of Qilian Mountains

摘要:

阐明不同放牧模式对土壤理化特性和物种多样性的影响,为祁连山东缘高寒草甸的管理利用提供参考。选择划区轮牧(RG)、禁牧(PG)、轻度放牧(LG)和生长季休牧(GSG)4种放牧模式下的样地,检测各样地间植被群落物种多样性、生物量和土壤养分等指标,并分析其影响因素。结果发现:1)LG样地0~30 cm土层土壤含水量最高,且20~30 cm土层LG的土壤含水量显著高于RG、GSG和PG样地的土壤含水量(P＜0.05),LG样地0~30 cm土层土壤容重最低,但放牧模式对土壤pH值无显著影响,pH值均在7.0~7.8;GSG样地10~20 cm土层土壤有机碳和全氮含量显著高于PG样地(P＜0.05),PG样地0~10 cm土层土壤全钾含量显著高于RG样地(P＜0.05),LG和GSG样地20~30 cm土层土壤全钾含量显著高于RG和PG样地(P＜0.05);2)LG样地物种均匀度、丰富度和Shannon-wiener指数均最高;3)冗余分析表明,不同放牧模式下土壤全钾、含水量、容重和pH值等是影响群落物种多样性的重要因素。综合分析,轻度放牧模式能有效改善草地土壤和植被状况。

Abstract:

This study investigated the effects of grazing patterns on soil physical and chemical characteristics and species diversity,to provide guidance for the restoration and management of alpine meadow in the eastern margin of Qilian Mountains.Four grazing regimes were used,including rotational grazing (RG),grazing prohibition (PG),light grazing (LG) and non-growing season grazing (GSG).Species diversity,vegetation biomass and soil nutrients were measured under each grazing regime.Our results showed that soil water content in the LG was highest in the 0~30 cm layer,and was significantly higher than in RG,GSG and PG in the 20~30 cm layers (P＜0.05).Soil bulk density was lowest in the 0~30 cm layers under LG compared with the other regimes.Grazing regime has no effects on soil pH.Soil organic carbon and total nitrogen under GSG were significantly higher than that under PG in the 10~20 cm layer (P＜0.05).Total potassium under PG was significantly higher than that under RG in the 0~10 cm layer (P＜0.05),and total potassium under LG and GSG was significantly higher than that of RG and PG in the 20~30 cm layers (P＜0.05).Species evenness index,richness index and shannon-wiener index were highest under LG.Redundancy analysis showed that total potassium,water content,bulk density and pH value were important factors affecting species diversity.Our results showed that the light grazing regime could effectively improve soil nutrition and species diversity of grassland.