珠江河口不同类型湿地土壤有机磷矿化过程及其影响因素研究

Processes and influencing factors of organic phosphorus mineralization in various wetland soils in the Pearl River Estuary,China

以珠江河口湿地土壤为研究对象,采用室内培养的实验方法,对研究区内3大类11种不同类型的土壤进行恒温控湿好气培养.通过分析土壤理化性质、土壤净磷矿化量和土壤净磷矿化速率等参数,探究珠江河口湿地土壤有机磷矿化过程及其影响因素.结果表明,研究区湿地土壤有机磷矿化速率在-126.47~99.767 5mg·kg^(-1)·d^(-1)范围内波动.在培养前15d土壤净磷矿化速率变化较大,后期趋于平缓且接近零值.其中,围垦湿地土壤有机磷矿化率能够在短时间内趋于稳定(15d),沟渠湿地土壤达到稳定时间相对较长(25d),而农村河流湿地土壤与城市河流湿地土壤有机磷矿化速率在整个培养期内均呈波动变化,达到稳定时间长达40d.在所有湿地类型中,城市河流湿地土壤有机磷的矿化或固定作用最大,围垦湿地土壤有机磷矿化速率波动幅度相对较小,而人工湿地土壤有机磷矿化速率则在整个培养期内无明显变化且接近于零值.土壤有机磷净矿化速率与有机质(SOM)、总碳(TC)、总氮(TN)、总氢(TH)、总磷(TP)的质量分数及土壤水土质量比均呈现显著负相关关系(P<0.01),而与pH和微生物量碳(MBC)等理化性质无显著相关性(P>0.05).研究结果可为滨海湿地的保护与管理提供理论指导.

Organic phosphorus mineralization of various wetland soils from the Pearl River Estuary were investigated using laboratory incubation experiments.Eleven kinds of soils from the three types of wetlands in three replicates were incubated under constant temperature and soil moisture in incubators under aerobic conditions.The physical and chemical properties,net phosphorus mineralization and net phosphorus mineralization rates of wetland soils were analyzed to reveal the processes and influencing factor of soil phosphorus mineralization.Our results showed that net phosphorus mineralization rates of wetland soils ranged from -126.47 to 99.767 5mg·kg^-1·d^-1.The net mineralization rate of soil phosphorus fluctuated in the first15 days of cultivation,and gradually approached to 0 in the following period.The net mineralization rates of organic phosphorus in reclaimed wetland soils became stable in a short period of 15 days,and that of ditch wetland soils need a long time of 25 days.The mineralization rates of organic phosphorus in rural and urban river soils got a fluctuation in the whole incubation period,and spent 40 days to get stable.Among these studied wetlands,organic phosphorus mineralization in urban river wetland soils exhibited the most effective fixation,while the rates of net phosphorus mineralization in reclaimed wetlands showed a weak fluctuation.The net mineralization rates of organic phosphorus in constructed wetlands had no obvious change and approached to 0.The net mineralization rates of soil phosphorus had got a negative relationship with w（SOM）,w（TC）,w（TN）,w（TH）,w（TP）and water content（P〈0.01）,and no significant correlations were observed between net phosphorus mineralization rates with pH and MBC（P〈0.05）.The findings of this study can provide a theoretical guidance for the conservation and management of coastal wetlands.