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【目的】研究陕北黄土区封禁小流域中不同类型生物结皮对土壤微生物量碳和氮含量的影响,为该地区植被恢复和生态重建提供参考。【方法】选取陕北黄土区吴起县合沟流域为研究区,以藻类地衣苔藓结皮、藻类地衣结皮、藻类苔藓结皮和物理结皮(对照)为研究对象,分析不同生物结皮类型对结皮层及其以下土层(2~5cm和5~10cm)土壤微生物量碳和氮含量的影响。【结果】与物理结皮相比,3种生物结皮均能显著提高结皮层的土壤微生物量碳和氮含量(P<0.05),改善效果的大小顺序为藻类地衣苔藓结皮>藻类苔藓结皮>藻类地衣结皮>物理结皮。生物结皮对结皮层以下土层土壤微生物量碳、氮含量的影响随土壤深度的加深而减小,其改良效果为藻类地衣苔藓结皮最好,藻类地衣结皮和藻类苔藓结皮次之。生物结皮的不同发育阶段与土壤微生物量碳和氮含量呈极显著正相关关系(P<0.01)。【结论】生物结皮的形成与发育能显著改善结皮层及其以下土层土壤微生物量碳和氮含量,提高表层土壤的生物活性。
【Objective】 The objective of this study was to investigate the effects of different types of biological crusts on the soil microbial biomass C and N in the closed drainage areas of the Loess Area in the north of Shaanxi Province and provide references for the restoration of vegetation and ecological restoration in this area. 【Method】 In this study, we selected the Heganggou watershed in Loess area of northern Shaanxi as study area, and took algae lichen crust, algal lichen crust, algal lichen crust and physical crust (control) On soil microbial biomass C and N contents in the crust and below soil layers (2 ~ 5cm and 5 ~ 10cm). 【Result】 Compared with the physical crust, all the three crusts could significantly increase the soil microbial biomass C and N (P <0.05). The order of improvement was algae lichen crust> algal lichen crust > Algae lichen crust> Physical crust. The effects of biological crusts on soil microbial biomass C and N in the soil below the crust decreased with the deepening of soil depth. The improvement effect was that the algal lichen Moss crusts were the best, followed by the algal lichen crusts and algal moss crusts . There was a significant positive correlation between soil microbial biomass carbon and nitrogen in different developmental stages of biological crusts (P <0.01). 【Conclusion】 The formation and development of biological crusts can significantly improve soil microbial biomass carbon and nitrogen content in the crust and below soils, and improve the biological activity of topsoil.