荒漠区踩踏生物土壤结皮对土壤微生物量的影响

doi:10.7522/j.issn.1000-694X.2018.00027

摘要/Abstract

摘要： 土壤微生物量可敏感指示土壤质量，是衡量荒漠地区生态恢复程度的重要生物学指标，而有关荒漠区人为踩踏生物土壤结皮与土壤微生物量关系的研究相对缺乏。以腾格里沙漠东南缘的人工植被固沙区和天然植被区人为踩踏生物土壤结皮下的沙丘土壤为研究对象，分别采集未踩踏、中度踩踏和重度踩踏结皮下0~5 cm和5~15 cm土样并测定土壤微生物量碳和氮。结果表明：人为踩踏藻-地衣结皮和藓类结皮可减少生物土壤结皮下土壤微生物量碳和氮，且土壤微生物量碳和氮随踩踏程度的增加而减少，重度踩踏显著减少土壤微生物量碳和氮（P<0.05），土壤速效磷、速效氮、全磷和全氮的损失是导致土壤微生物量碳和氮减少的重要因子。除踩踏程度外，土壤微生物量碳和氮也受结皮演替阶段的影响。人为踩踏的藓类结皮下土壤微生物量碳和氮显著高于藻-地衣结皮（P<0.05），表明演替晚期的藓类结皮比演替早期的藻-地衣结皮抗干扰能力更强；无论季节如何更替，土壤微生物量碳和氮均表现为未踩踏 > 中度踩踏 > 重度踩踏；人为踩踏结皮下土壤微生物量碳和氮均表现明显的季节变化，夏季 > 秋季 > 春季 > 冬季。腾格里沙漠人工植被固沙区和天然植被区人为踩踏生物土壤结皮可减少土壤微生物量，表明人为踩踏生物土壤结皮可引起土壤质量下降，导致荒漠生态系统的退化。因此，保护荒漠区生物土壤结皮有利于荒漠生态系统的修复。

关键词: 生物土壤结皮, 人为踩踏, 踩踏程度, 结皮演替阶段, 土壤微生物量, 时空动态

Abstract: Soil microbial biomass could be used as significant biological indicator to reflect soil quality and ecological restoration of sandy land. However, little was known on the relationship between human trampling to biocrusts and soil microbial biomass in desert areas. To explore the effects of human trampling to biocrusts on soil microbial biomass, sand soil under human trampling to biocrusts was served as the research object and soil underneath non-trampling biocrusts was the reference in artificial and natural vegetation areas at the southeastern edge of the Tengger Desert. Trampling to biocrusts was divided into three levels depending on the trampling degree to biocrusts:non-trampling, medium trampling and severe trampling, respectively. Soil samples were taken from the three trampling degrees in 0~5 cm and 5~15 cm soil depth, respectively, and microbial biomass carbon and nitrogen were measured. The results showed that human trampling to cyanobacteria-lichen and moss crusts could reduce soil microbial biomass carbon and nitrogen. Moreover, soil microbial biomass carbon and nitrogen decreased as the trampling degree to biocrusts increased. Severe trampling to cyanobacteria-lichen and moss crusts significantly declined soil microbial biomass carbon and nitrogen (P<0.05). The loss of soil available phosphorus, available nitrogen, total phosphorus and total nitrogen act as the important factors which caused the reduction of soil microbial biomass carbon and nitrogen. In addition to the trampling degree, soil microbial biomass carbon and nitrogen after human trampling to biocrusts are also significantly influenced by the successional stage of crusts (P<0.05). Soil microbial biomass carbon and nitrogen under trampled moss crusts significantly higher than trampled cyanobacteria-lichen crusts. This indicated that late-stage moss crusts had more stronger anti-interference capability than early-stage cyanobacteria-lichen crusts(P<0.05). In addition, there was a consistent law of soil microbial biomass carbon and nitrogen under biocrusts no matter how seasons change, follow orders:non-trampling > medium trampling > severe trampling. Moreover, there were seasonal changes of soil microbial biomass under trampling biocrusts, follow orders:summer > autumn > spring > winter. Therefore, trampled biocrusts could decrease soil microbial biomass in artificial and natural vegetation areas at southeastern edge of the Tengger Desert, indicating the degradation of soil and the desert ecosystem. The results showed that the protection to biocrusts could recover the desert ecosystems in desert areas.

Key words: biocrusts, human trampling, trampled degree, successional stage of crusts, soil microbial biomass, temporal dynamic

中图分类号:

S153.6

杨航宇, 刘长仲, 刘艳梅, 杨昊天. 荒漠区踩踏生物土壤结皮对土壤微生物量的影响[J]. 中国沙漠, 2019, 39(2): 35-44.

Yang Hangyu, Liu Changzhong, Liu Yanmei, Yang Haotian. Effects of Trampling Biocrusts on Soil Microbial Biomass in Desert Areas[J]. Journal of Desert Research, 2019, 39(2): 35-44.

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