河口湿地红树林植被恢复对土壤养分动态的影响

Effects of Mangrove Vegetation Restoration on Soil Nutrient Dynamics in Estuarine Wetlands

以泉州湾河口人工红树林湿地为研究对象,以光滩为对照,采集0—10,10—20,20—30 cm土层土壤,研究不同红树林恢复(桐花树、秋茄、秋茄-桐花树混交林)对河口湿地土壤pH、有机质及主要养分元素(氮磷钾)的影响。结果表明:不同植被恢复模式下土壤pH和有机质含量呈明显的垂直变化特征,相对于无植被的光滩(恢复前),红树林植被恢复显著降低了土壤pH(P<0.05),但增加了土壤有机质含量(P<0.05)。不同红树林恢复模式下,土壤碱解氮、有效磷、速效钾和全钾含量均大致表现为随土层深度的增加而增加,而全磷含量则表现为随深度的增加而降低。相对于恢复前,红树林植被恢复均增加了表层土壤主要养分(氮磷钾)含量,其中,以桐花树—秋茄混交林的影响最为显著(P<0.05)。综上,不同模式红树林植被恢复对河口湿地土壤理化性质和养分动态具有明显的调节作用,其中,混交林模式通过高效利用地上地下空间,改善土壤结构和质量,增加生物量和养分归还量,显著改善了土壤养分动态,是河口区植被恢复的优选手段。研究结果可为加强河口红树林湿地养分管理、维护湿地系统养分平衡提供科学参考。

In order to investigate the effect of vegetation restoration on soil pH,organic matter and main nutrient elements(nitrogen(N),phosphorus(P)and potassium(K)),taking the tidal flat as the control,different mangrove restoration modes(Aegiceras corniculatum,Kandelia obovate and mixed forest)in the Quanzhou Bay estuarine wetland were selected in this study.The results showed that soil pH and organic matter contents varied vertically under different restoration modes.Compared with the control,the restoration of mangrove significantly decreased soil pH(P<0.05),but increased soil organic matter contents(P<0.05).Under different restoration modes,the contents of alkali-hydrolyzable N,available P,available K,and total K increased with the increase of soil depth,while the contents of total P decreased with soil depth.Compared with the control,the mangrove restoration increased the contents of main soil nutrients(N,P,and K)in the surface soil,especially in the mixed forest(P<0.05).Our results indicated that different mangrove restoration modes have significant regulatory effects on soil physiochemical properties and nutrient dynamics.Among them,the mixed forest mode significantly improved soil nutrient dynamics through efficient utilization of aboveground and underground space,improving soil structure and quality,and increasing biomass and nutrient return,which is the optimal model for vegetation restoration in the estuarine area.The results can provide scientific reference for strengthening nutrient management and maintaining nutrient balance of estuarine mangrove wetland.