库布齐沙漠东部植被恢复对土壤生态化学计量的影响

Effects of vegetation restoration on soil stoichiometry in the eastern Hobq Desert

为阐明植被恢复对风沙土生态化学计量特征的影响,以库布齐沙漠东段流动沙地、半固定沙地、油蒿固定沙地和沙柳固定沙地为研究对象,分析植被生物量和不同深度土层(0~60 cm)土壤C、N、P化学计量特征时空变化及其相关性。结果表明:(1)土壤C、N含量随植被恢复明显增加,而土壤P含量增幅较小,均在沙柳固定沙地达到最大值(5.86 g·kg^(-1)、0.41 g·kg^(-1)、1.74 g·kg^(-1)),各阶段土壤C、N、P含量均随土层加深逐渐降低,土壤P含量在各土层间差异较小。(2)不同阶段或土层间土壤化学计量比差异显著,随植被恢复土壤C:N先减小后增大,而C:P和N:P均逐渐增大,土壤C:P和N:P均随土层加深逐渐减小,而C:N则无明显变化规律。(3)土壤C、N、P两两间呈极显著正相关,均与地上和凋落物生物量呈显著正相关,土壤C:N与C:P、N:P均无显著相关关系,而土壤C:P与N:P呈显著正相关,且土壤C:P和N:P均与地上、地下和凋落物生物量呈显著正相关。综上所述,人工建植促进植被恢复可显著影响土壤C、N、P含量及化学计量特征,进而有效改善土壤理化性状,提高荒漠生态系统C、N固存能力。

To clarify the impact of vegetation restoration on stoichiometric characteristics,aeolian sandy soil,mobile sandy land,semi-fixed sandy land,Artemisia ordosica-fixed sandy land,and Salix psammophila-fixed sandy land in the eastern part of Kubuqi were selected as research areas.This research analyzed temporal and spatial changes and the correlations among vegetation biomass and soil carbon,nitrogen,and phosphorus stoichiometry at different depths(0-60 cm).Results show the following:(1)the content of soil C and N significantly increased with vegetation restoration,whereas the content of soil P slightly increased and reached a maximum value in Salix cheilophila-fixed sandy land(5.86 g·kg^(-1),0.41 g·kg^(-1),1.74 g·kg^(-1)),the content of C,N,and P in soil decreased with soil layer depth,and the difference in the P content in the soil layer was small.(2)The soil stoichiometric ratio at different stages or soil layers was significantly different with vegetation restoration.Soil C:N first decreased and then increased,whereas C:P and N:P increased gradually.Soil C:P and N:P decreased gradually with deepening of the soil layer,whereas C:N had no obvious change.(3)Soil C,N,and P were significantly and positively correlated with aboveground and litter biomass and there was no significant correlation between soil C:N and C:P and N:P.However,soil C:P was positively correlated with N:P,and soil C:P and N:P were positively correlated with aboveground,underground,and litter biomass.In conclusion,artificial planting to promote vegetation restoration can significantly affect the content and stoichiometric characteristics of soil C,N,and P to effectively improve soil physical and chemical properties and enhance the carbon and nitrogen sequestration capacity of the desert ecosystem.