闽江河口互花米草与短叶茳芏湿地土壤无机硫形态分布特征及其影响因素

选择闽江口鳝鱼滩不同淹水环境下两条样带(A样带,远离主潮沟且退潮后无积水;B样带,靠近主潮沟且退潮后有积水)上的短叶茳芏湿地和已被互花米草入侵(入侵前为短叶茳芏湿地)的互花米草湿地为研究对象,探讨不同类型湿地土壤无机硫赋存形态的分布特征及其主控因素.结果表明,B样带上互花米草湿地和短叶茳芏湿地土壤中的水溶性硫(H_2O-S)和吸附性硫(Adsorbed-S)含量总体上低于A样带,而盐酸可溶性硫(HCl-Soluble-S)和盐酸挥发性硫(HCl-Volatile-S)含量则高于A样带.短叶茳芏湿地和互米草湿地土壤中不同形态无机硫的含量在两条样带上整体均表现为HCl-Soluble-SH_2O-SAdsorbed-SHCl-Volatile-S,且二者的总无机硫含量分别占其TS含量的9.02%~15.50%和8.04%~12.73%.与短叶茳芏湿地相比,互花米草入侵分别使A样带土壤中H_2O-S、Adsorbed-S、HCl-Soluble-S、HCl-Volatile-S和总无机硫含量减少了35.2%、36.4%、16.8%、1.8%和26.12%;但使B样带表层土壤的总无机硫含量及0~20 cm土层的HCl-Soluble-S和HCl-Volatile-S含量分别增加了8.34%、15.34%和5.71%.研究发现,非长期淹水条件下,互花米草入侵后可降低湿地土壤有效硫的供给能力;长期淹水条件下,互花米草入侵可通过提高土壤中HCl-Soluble-S的含量增加金属硫化物沉淀,而挥发性硫含量的同步增加则可能对植被生长(特别是根系发育)产生不利影响.

Distributions characteristics and influencing factors of inorganic sulfur forms in soil of Spartina alterniflora marsh and Cyperus malaccensis marsh in the Min River Estuary

To explore the distribution characteristics and crucial controlling factors of inorganic sulfur (IS) in soils of salt marsh in the Shanyutan marsh of the Min River estuary, two transects (A transect, away from the main tidal channels with no flooding as the tide ebbs; B transect, near the main tidal channels with flooding as the tide ebbs) with different flooding regimes were chosen and the Cyperus malaccensis and Spartina alterniflora marshes(C. malaccensis community before invaded by S. alterniflora) were studied. Compared with A transect,H₂O-S and Adsorbed-S contents were lower, while HCl-Soluble-S and HCl-Volatile-S contents were higher in the soils of C. malaccensis and S. alterniflora marshes in B transect. The contents of inorganic sulfur in soils of C. malaccensis marsh and S. alterniflora marshes in both two transects were in the order of HCl-Soluble-S > H₂O-S > Adsorbed-S > HCl-Volatile-S, and the total inorganic sulfur(TIS) contents accounted for 9.02%~15.50% and 8.04%~12.73% of the total sulfur (TS) contents in the two marshes, respectively. Compared with C. malaccensis marsh, H₂O-S, Adsorbed-S, HCl-Soluble-S, HCl-Volatile-S and TIS contents in A transect decreased by 35.2%, 36.4%, 16.8%, 1.8% and 26.12%, respectively; whereas TIS contents in top soil and HCl-Soluble-S and HCl-Volatile-S contents in 0~20 cm soil layers in B transect increased by 8.34%, 15.34% and 5.71%, respectively, in soils of S. alterniflora invasion marsh. This study found that, under non-flooding condition, the supply capacity of available sulfur in marsh soils might be decreased as it was invaded by S. alterniflora. However, under long-term flooding regimes, the invasion of S. alterniflora might increased the precipitation of metal sulfide in soils by increasing the contents of HCl-Soluble-S. Meanwhile, the increase of HCl-Volatile-S content might produce adverse effects on the growth of plants (particularly for root development).