贵州喀斯特石漠化地区苔藓结皮对土壤酶活性及碳氮磷含量的影响

Effects of Moss Crusts on Soil Enzyme Activities and Contents of Soil Carbon,Nitrogen and Phosphorus in a Karst Rocky Desertification Area of Guizhou

【目的】探索在喀斯特石漠化退化生态系统下苔藓结皮及覆被土壤的养分的变化特征,以期为喀斯特石漠化生态环境修复提供新的理论参考。【方法】以我国贵州典型喀斯特石漠化生态系统-花江石漠化综合治理示范区的苔藓结皮覆被土壤、移除结皮(一年后)以及裸土为研究对象,采用双因素分析方法探讨不同石漠化(无、轻、中、重度)生境下有无结皮覆被及不同土层深度(结皮层、0~5 cm、5~10 cm)对土壤酶活性、土壤碳氮磷含量及计量特征的影响。【结果】(1)苔藓结皮层土壤脲酶和β-葡萄糖苷酶活性均随着石漠化的等级的升高而升高,而蔗糖酶和碱性磷酸酶则无显著变化;无石漠化区的土壤有机碳含量和碳/氮、碳/磷、氮/磷比值显著高于轻、中、重度石漠化区。(2)土壤碳氮磷含量及计量特征、酶活性在结皮层与结皮下土层间存在显著差异,结皮层显著高于结皮下0~5 cm和5~10 cm土壤。(3)与苔藓结皮相比,除脲酶活性外,移除结皮一年后的土壤蔗糖酶、碱性磷酸酶、β-葡萄糖苷酶活性、碳氮磷含量及计量特征均有所减少,而与裸土相比则无明显变化。【结论】苔藓结皮的存在提高了其覆被土壤的酶活性及碳氮磷含量,突出了苔藓结皮在退化喀斯特石漠化生境中生态功能的重要性。

[Objective]Exploring the characteristics of nutrient changes in moss crusts and covered soil in karst rocky desertification,and its positive ecological benefits could provide a new theoretical reference for the ecological environment restoration of karst rocky desertification.[Method]In this paper,soil covered by moss crusts,soils deprived of biocrust-forming mossess(one year later)and bare soils in different levels of rocky desertification(none,light,moderate and severe)in the typical rocky desertification ecosystem–Huajiang rocky desertification area in Guizhou province of China,were used to investigate the effects of moss crusts on soil enzyme activities,and contents of soil carbon,nitrogen,phosphorus and stoichiometric characteristics of different karst desertification grades(none,light,moderate,and severe)and different soil depths(crust layer,0-5 cm,and 5-10 cm).[Result](1)Activities of urease(UE)andβ-glucosidase(BG)in moss crust layer increased with the degradation progress of karst desertification.While soil sucrase(SC)and alkaline phosphatase desertification(AKP)did not change significantly.SOC,C/N,C/P,and N/P contents were significantly higher in sample sites of no rocky desertification than those of light,moderate,and sever grades.(2)Soil carbon,nitrogen and phosphorus contents and stoichiometric characteristics,enzyme activities(SC,BG,AKP)in crust layer were significantly higher than those in sub-crust layers(0-5 cm and 5-10 cm).(3)Compared with moss crusts,activities of soil SC,AKP,BG and contents of carbon,nitrogen and phosphorus and stoichiometric characteristics decreased significantly one year after crust removal,while did not significantly change compared with bare soil.[Conclusion]The existence of moss crusts improve soil enzyme activities,and carbon,nitrogen and phosphorus contents,which highlights the important ecological function of moss crusts in degraded karst rocky desertification ecosystems,and its positive ecological benefits could provide a new theoretical reference for the ecological environment restoration of karst rocky desertification.