Abstract: A laboratory simulation experiment was conducted to study the effects of substrate type and water level on the expansion of invasive species Spartina alterniflora. Several phenotypic parameters of S. alternilora seedlings, such as survival rate, height growth, biomass, and biomass allocation, were determined. The results showed that substrate type, water level, and their interaction had significant effects on the S. alterniflora seedlings growth, and the interaction of substrate type and water level significantly affected the survival rate of seedlings. On the same substrate types, the decrease of water level increased the root length significantly. On sand substrate, the height growth was inhibited with decreased water level, and the rhizome length was significantly shorter than that on sandsoil mixture and soil substrate; on sandsoil mixture and soil substrate, the growth of seedlings was the best at moderate water level, and the rhizome length decreased significantly with decreased water level. It was deduced that the expansion rate of S. alterniflora population varied with habitat, being higher on sand soil mixture and soil substrate.

Key words: Subsurface drip irrigation, Lower limit of irrigation, Soil water suction, Growth, Yield, Plastic tunnel