Influence of soil moisture and electrical conductivity on the growth of Phragmites australis (Cav.) in the Keriya oasis, China

In this study, we sought to explore the changes of soil moisture and soil electrical conductivity (EC), as well as to study the relationships between these soil properties and the vegetative indexes of plant coverage, height and crown density and diameter during the Phragmites australis (P. australis) growth period. By combining floristic and edaphic variables (soil moisture and EC), we found that at 0–10 cm depth, the soil moisture varied greatly, while the soil moisture at 10–50 cm depth, EC at 0–50 cm depth, and vegetation properties varied only moderately. A great amount of evaporation offered a possible reason for this moderate variability in soil moisture and EC. Geostatistical analyses revealed that the soil moisture at 0–50 cm depth, and the density of P. australis (Cav.) had a strong spatial autocorrelation, while the EC at 0–50 cm depth had only a weak spatial autocorrelation depending on the nugget effect. Furthermore, there was a positive correlation between the soil moisture and vegetation characteristics at the depth of 0–50 cm, but there was a negative correlation between EC and vegetation characteristics at the depth of 30–50 cm. Furthermore, an increase in soil moisture had a positive effect on P. australis (Cav.) growth, while an increase in EC had a negative effect.