生物土壤结皮对东祁连山高寒草甸土壤特性的影响

Effects of biological soil crusts on soil properties ofalpine meadows in eastern Qilian Mountains

摘要:

为阐明生物土壤结皮(Biological soil crusts,BSCs)在东祁连山高寒草甸生态系统中的生态功能,分土层(0~2、2~5、5~10、10~20和20~30 cm)比较了BSCs覆盖区和草本(Herbaceous,Herbs)植物覆盖区的土壤特性(含水率、全氮、全磷、全钾、有机碳、速效氮、速效磷、速效钾、微生物量碳氮含量、脲酶、蔗糖酶和碱性磷酸酶活性)。结果表明:与Herbs覆盖区相比,1)BSCs可改善高寒草甸的土壤理化性质,土壤含水率、全氮、全磷、速效磷、速效氮和有机碳含量最高可分别提高9.83%、55.8%、23.36%、39.29%、18.64%和5.43%;2)BSCs使0~2、5~20 cm土层蔗糖酶活性升高,降低0~20 cm土层脲酶活性,且显著增加2~5 cm土层的碱性磷酸酶活性(P＜0.01);3)BSCs降低了0~20 cm土层土壤微生物生物量氮和0~5 cm土层的微生物生物量碳含量;4)结构方程模型表明,BSCs对土壤特性的影响大于Herbs,Herbs仅对速效钾含量和脲酶活性影响显著,而BSCs对参试指标均为显著的正效影响(P＜0.01),尤其是对土壤微生物生物量碳氮的影响。以上结果表明BSCs具有改善高寒草甸土壤环境质量的生态功能,对高寒草甸生境的恢复与改善有促进作用。

Abstract:

In order to clarify understand the ecological function of Biological Soil Crusts (BSCs) in the alpine meadow ecosystem of the eastern Qilian Mountains,the soil properties of the BSCs coverage area were compared with those of Herbaceous coverage area (Herbs) in layers:0~2,2~5,5~10,10~20,and 20~30 cm.The soil properties included soil water content,total nitrogen,total phosphorus,total potassium,organic carbon,available nitrogen,available phosphorus,available potassium,microbial biomass carbon and nitrogen,urease activity,sucrase activity and alkaline phosphatase activity.The results showed that compared with Herbs coverage area:1) BSCs improved the soil physical and chemical properties of alpine meadows,soil water content,total nitrogen,total phosphorus,available phosphorus,available nitrogen,and organic carbon content can be increased by 9.83%,55.8%,23.36%,39.29%,18.64%,and 5.43%,respectively;2) BSCs significantly increased the sucrase activity in the 0~2 and 5~20cm layers,reduced the urease activity in the 0~20cm layers,and significantly increased the alkaline phosphatase activity in the 2~5cm layers (P＜0.01);3) BSCs reduced the soil microbial biomass nitrogen in the 0~20cm layers and the microbial biomass carbon in the 0~5cm layers;4) The structural equation model showeds that BSCs had greater impact on soil properties than Herbs.Herbs only had significant effect on available potassium and urease,while BSCs had significant positive effect on the test indicators (P＜0.01),especially the impact on soil microbial biomass carbon and nitrogen.In conclusion,BSCs had demonstrated the ecological function of improving the soil environmental quality of alpine meadows,and could play positive role in the restoration and improvement of alpine meadow habitats.