Ecology responses to soil properties of Phragmites australis community were experimentally investigated through 103 field studies along the coast-inland regions in Yellow River Delta of China, for determining correlations in such soil-plant systems. The field investigation were divided into five sample groups of water-salinity based on the variation of soil water content and electronic conductivity measured at the 0–20 cm soil depth in terms of the principal components analysis and hierarchical cluster analysis.
P. australis exhibits phenotypic plasticity as the response to soil water content and salinity. Both waterlogging and soil salinity stress are two key factors determining the community characteristics and plant functional traits. Comparing the representative results of the P. australis community traits among the sample groups showed that P. australis reached optimal characteristics and traits at the soil water content values ~30% and electronic conductivity values ~1 ms/cm in Yellow River Delta. The non-linear relationship, obviously with a soil moisture threshold, was established for P. australis. In contrast to semiarid saline watershed, the different salinity levels that inhibit community coverage were observed. Community traits and SPAD values could be as indication traits for waterlogging; while, functional responses such as morphology and leaf characteristics could be serve as indication characteristics for salinity.