闽江河口互花米草入侵湿地土壤无机硫赋存形态及其影响因素

选择闽江河口鳝鱼滩的互花米草湿地为研究对象,基于时空互代法,探讨了不同互花米草入侵年限（SA1： 5-6 年;SA2： 8-10 年;SA3： 12-14年）湿地土壤的无机硫赋存形态及其主要影响因素。结果表明,随着互花米草入侵年限的增加,湿地土壤的水溶性硫（H₂O-S）含量整体呈增加趋势,而吸附性硫（Adsorbed-S）、盐酸可溶性硫（HCl-Soluble-S）和盐酸挥发性硫（HCl-Volatile-S）含量整体均呈降低趋势。相对于SA1,SA2、SA3土壤的H₂O-S含量分别增加了10.02%和2.68%,而其Adsorbed-S、HCl-Soluble-S和HCl-Volatile-S含量分别降低了9.02%、10.95%、7.57%和15.61%、32.89%、15.14%。湿地土壤的总无机硫（TIS）含量、TIS储量及其占全硫（TS）储量的比例均随互花米草入侵年限的增加而降低,且这种降低主要取决于Adsorbed-S、HCl-Soluble-S和HCl-Volatile-S的贡献。此外,随着互花米草入侵年限的增加,影响湿地土壤不同形态无机硫赋存的环境因子均发生了较大变化,其中土壤颗粒组成、EC和pH的改变对无机硫赋存形态的影响最为明显。研究发现,随着互花米草入侵年限的增加以及该区对互花米草定期刈割活动的进行,湿地土壤无机硫养分可能将继续降低并逐渐趋于缺乏状态,长期而言将减弱互花米草自身的入侵能力。

Variations of inorganic sulfur fractions and main influencing factors in marsh soils with different years of Spartina alterniflora invasion in the Min River estuary

In order to investigate the effects of Spartina alterniflora invasion on the variations of inorganic sulfur fractions and its main influencing factors in soils, the marshes with different invasion years of S. alterniflora (SA1:5-6 a; SA2:8-10 a; and SA3:12-14 a) in Shanyutan of the Min River estuary were studied by the method of space-for-time substitution. Results indicated that the contents of water-soluble-sulfur (H₂O-S) in soils generally increased with increasing invasion years, while those of adsorbed-sulfur (Adsorbed-S), HCl-soluble-sulfur (HCl-Soluble-S) and HCl-volatile-sulfur (HCl-Volatile-S) generally decreased. Compared with SA1, the levels of H₂O-S in soils of SA2 and SA3 increased by 10.02% and 2.68%, whereas those of Adsorbed-S, HCl-Soluble-S and HCl-Volatile-S decreased by 9.02%, 10.95%, 7.57% (SA2) and 15.61%, 32.89%, 15.14% (SA3), respectively. The total inorganic sulfur (TIS) contents, TIS stocks and their proportions in total sulfur (TS) stocks in marshes decreased with the increasing invasion years, and the decline mainly rested with the contributions of Adsorbed-S, HCl-Soluble-S and HCl-Volatile-S. Moreover, with increasing invasion years, the environmental factors affecting the fractions of inorganic sulfur changed greatly. Thereinto, the alterations of soil grain composition, electrical conductivity (EC) and pH showed great effects on the variations of inorganic sulfur fractions. This study found that, with the increase of invasion years and the implementation of regular mowing activities for S. alterniflora, the inorganic sulfur nutrient in marshes would decline and become deficient, which might weaken the invasion capacity of S. alterniflora in the long term.