互花米草入侵对滨海湿地不同质地土壤碳氮磷及其生态化学计量比的影响

为了阐明外来物种入侵对滨海湿地不同质地土壤碳(C)、氮(N)、磷(P)及其生态化学计量比的影响，对福建省滨海地区东湖湿地两种质地土壤的土著种与入侵种植被下土壤C、N、P含量及其生态化学计量特征与影响因素进行了测定与分析。研究结果表明：相同植被下，壤质土的C、N、P及其计量比均高于砂质土。互花米草入侵增加了两种质地土壤的C、N含量及碳磷比(C/P)、氮磷比(N/P)，降低了土壤有效磷(AP)、P含量与碳氮比(C/N)，其中砂质土的土壤N含量显著增加了近1倍(P<0.05),AP含量下降近70%，壤质土的C/P增加了近2倍(P<0.05)。不同质地土壤中铵态氮(NH₄⁺-N)和硝态氮(NO₃^–-N)含量对互花米草入侵的响应不同，在壤质土中，互花米草入侵后降低了50%的NH₄⁺-N含量，增加了近3倍的NO₃^–-N含量(P<0.05)；而在砂质土中，互花米草入侵后土壤NH₄

Effects of Spartina alterniflora Invasion on Soil Carbon, Nitrogen and Phosphorus and Their Ecological Stoichiometric Ratios in Coastal Wetlands of Different Textures

In order to clarify the effects of alien species invasion on soil carbon (C), nitrogen (N), phosphorus (P) and their eco-stoichiometric ratios in different textures of coastal wetlands, the contents of soil C, N, P, and their eco-stoichiometric characteristics, as well as influencing factors in the both textures of Donghu Wetland in coastal areas of Fujian Province were measured and analyzed. The results showed that both of the different texture soils, after Spartina alterniflora invasion, the contents of C and N showed an increasing trend, but the soil P showed a decreasing trend, and the soil N content in sandy soil increased by nearly two times (p<0.05) while the P contents of the soils in loamy soils decreased significantly by 2.5 times (p<0.01). The soil C/P ratio and N/P ratio increased, and the C/P of loam increased by nearly 2.8 times (p<0.05). In sandy soil, soil N content was significantly negatively correlated with bulk density (BD), but positively correlated with water content (WC) (p<0.05). In general, the impact trends of Spartina alterniflora invasion on soil C, N, P and their eco-stoichiometric ratios in different textures were roughly the same, but varied degrees, expressing more significantly on soil N in sandy soil, while on soil P in loam soil.