Spatial variation characteristics of chloride, nitrate and sulfate in Phragmites communis soil system, Northeast China

The appropriate amount of inorganic anions in soil could promote the growth of plant, while the excess amount of anions could lead to soil salinization. The research about the spatial variation characteristics of inorganic anions in soil was of great significance to salinization control and ecological restoration. The present research analyzed the contents of the chloride (Cl-), nitrate (NO3-) and sulfate (SO42-) by ion chromatography in soil of Phragmites communis from sampling sites in Northeast China of 12, from June to October in 2011. The results showed that the average contents of chloride, nitrate and sulfate were 292.67, 297.14 and 367.49 mg·kg-1, respectively. The space distribution of the total content of the three tested anions was affected by seawater intrusion, physi-chemical property of soil and hydrothermal conditions. Dandong and Panjin where soil affected by seawater intrusion had higher contents of anions in soil compared with Daqing which heavier soil salinization. The distribution of the total content of the three anions from June to October was affected by hydrothermal condition and the requirement of P. communis from June to October. The content of anion was the highest in June which decreased from July with the change of hydrothermal conditions and growth period. The content of chloride in soil was influenced by seawater intrusion, degree of soil salinization and human activities. All of Dandong and Panjin in which soil affected by seawater intrusion, Daqing and Changling in which soil salinization was heavier, and Changchun and Nehe in which soil affected by human activities had higher content of chloride in soil. Nitrate content in soil was influenced by hydrothermal conditions and the requirement of P. communis. Mudanjiang, Tongliao, Dandong, Longwan and Nehe which had warmer and wetter hydrothermal conditions had higher nitrate in soil. The space distribution of sulfate content was affected by precipitation. There were higher sulfate contents in soil in the areas with fewer precipitation such as Nehe and Daqing. The transportation of the three anions in P. communis was active.