外源磷在2种母质发育米槠林土壤中的分配及影响因素

Distribution of Exogenous Phosphorus in Castanopsis carlesii Forest Soil Developed from Two Parent Materials and Its Influencing Factors

了解外源磷在不同母质森林土壤中的转化特性,对合理施肥和森林生态系统可持续发展和经营具有重要意义。分别以砂岩和花岗岩发育米槠林土壤为研究对象,通过添加NaH_(2)PO_(4)的室内培养实验,测定磷添加后土壤磷组分变化特征,旨在探究外源磷在亚热带不同母质森林土壤中磷转化特性,并通过建立磷组分变化量与土壤理化性质、土壤质地等的关联性,明确影响外源磷转化的驱动因子。结果显示:磷添加后,砂岩和花岗岩发育土壤中不同活性无机磷组分的含量显著增加,但变化幅度不同,顺序依次为NaOH-Pi>Resin-Pi>NaHCO_(3)-Pi;磷添加后砂岩发育米槠林土壤不同活性有机磷组分含量均增加,而花岗岩米槠林土壤各有机磷含量则显著降低;磷添加后,砂岩和花岗岩发育土壤酸性磷酸酶活性均显著降低,微生物量磷则显著增加。冗余分析(RDA)表明,游离铁含量、阳离子交换量和土壤质地是影响外源磷在土壤不同磷组分转化的关键因子。研究结果有助于了解外源磷在土壤不同磷组分中的分配特征,有望为中亚热带森林土壤合理施磷肥提供理论依据。

Understanding the transformation characteristics of exogenous phosphate in forest soils of different parent materials is important for rational fertilization and sustainable development and management of forest ecosystems.The soil of Castanopsis carlessi developed in sandstone and granite was taken as the research object respectively,aimed to investigate the exogenous phosphate transformation characteristics of phosphate in subtropical forest soils of different parent materials by determining the characteristics of soil phosphorus fraction changes after NaH_(2)PO_(4) addition through indoor incubation experiments,and the driving factors influencing exogenous phosphate transformation were clarified by establishing the correlation between the amount of phosphorus fraction change and soil physicochemical properties.The results showed that phosphate addition significantly increased the content of different active inorganic phosphorus fractions in sandstone and granite developmental soils,but the magnitude of the changes varied in the order of NaOH-Pi>Resin-Pi>NaHCO_(3)-Pi.The contents of different active organic phosphorus fractions in sandstone-developed forest soils increased after phosphate addition,while the contents of each organic phosphorus in granite-developed forest soils decreased significantly.The phosphate addition significantly decreased acid phosphatase activity and significantly increased microbial phosphorus in both sandstone and granite-developed soils.Redundancy analysis(RDA)indicated that free iron oxide,cation exchange capacity and soil texture were the key factors affecting the conversion of exogenous phosphate in different phosphorus fractions of the soil.The results of study can help to understand the distribution characteristics of exogenous phosphate in different phosphorus fractions of soil,and are expected to provide a theoretical basis for rational phosphorus fertilization in forest soils in the central subtropics.