Soil Properties and Reeds(Phragmites Australis) Wetland Restoration in Coastal Salinity Area in the Yellow River Delta Based on Canonical Correspondence Analysis

In order to better understand relations between wetland restoration of Phragmites Australis and environmental factors,three representative regions(alkali-saline patches,natural recovery and recovery of artificial control) wetland of Phragmites Australis were studied in the Yellow River Delta.The Canonical correspondence analysis(CCA) was used to study characteristics of reed communities and corresponding site conditions at different stages of restoration.Key environmental factors affecting wetland restoration of Phragmites Australis was discussed.The results showed that absolute concentrations of Na+,Cl-,SO42-,Mg2+,Ca2+ and K+ were decreased gradually,HCO3-was increased gradually,pH and soluble Ca2+ content were in a supplementary relation with each other in the recovery process.Total nitrogen,organic matter content were increased with the Phragmites Australis in a positive trend in succession,total phosphorus content changed only slightly.Soil salinity(TS),chlorine-sulfur ratio(Cl-/SO42-),sodium adsorption ratio(SAR),K+ with the axis 1 showed a significant positive correlation,while the water depth,recovery time,pH,soil organic matter(OM) showed a significant negative correlation.Plant height and TS,Cl-/SO42-,SAR,K+ were significantly related,coverage,biomass and WD,RS,pH,OM indicators were positively related.The salinity,chlorine-sulfur ratio,Na+ and water depth which affected the reed wetland area as a major constraint factor were determined.