Keywords: 
• 滨海盐碱地 /
• 沙枣 /
• 绒毛白蜡 /
• 土壤化学特性

Abstract: In order to compare improving effect of the forests for heavy saline-alkali soil ,the soil pH ,soil salt content ,soil organic matter ,available potassium and cation exchange capacity of different layer (0-20 cm ,20-50 cm ,50 -80 cm) in different seasons for pure forest of Elaeagnus angustifolia & Fraxinus velutina had been studied .The results showed that different forests could provide different effects for dif-ferent chemical properties in different seasons .In June ,the soil pH of different soil layers for Elaeagnus angusti f olia forest soil decreased in different degree ,and the soil pH of 20 -50 cm in depth decreased most ,cation exchange capacity of 20-50 cm in depth was higher obviously than that of CK ,but the soil salt content ,soil organic matter and available potassium didn't obviously change ;the soil pH of different soil layers for Fraxinus velutina forest soil also decreased in different degree ,available potassium content of different soil layers obviously increased ,and cation exchange capacity of 20-50 cm in depth was higher obviously than that of CK ,yet the soil salt content and soil organic matter content didn't obviously change . In October ,effect of improvement of Fraxinus velutina about the soil pH ,soil organic matter and cation exchange capacity was better than that of Elaeagnus angustifolia ,for Fraxinus velutina forest soil ,the soil pH of 50 cm-depth obviously decreased ,soil organic matter of 50 cm-depth increased more ,cation ex-change capacity of different layers was higher obviously than that of CK ;for Elaeagnus angusti f olia for-est soil ,the soil pH of 20 cm-depth obviously decreased ,soil organic matter and cation exchange capacity of 20 cm-depth increased more;soil salt content of Elaeagnus angusti f olia forest soil decreased more than that of Fraxinus velutina forest soil ,and soil salt content of 20 cm-depth for two forests soils decreased most ;available potassium content of 20 cm-depth for two forests soils was higher than that of CK .Com-pared with October and June ,the soil pH and soil salt content of different layers for two forests soils in October were all lower than that those in June ,and soil organic matter of different layers for two forests soils in October was higher than in June ;available potassium content of different layers for Elaeagnus an-gusti f olia forest soil in October was higher than that in June ,and available potassium content of different layers for Fraxinus velutina forest soil was all lower than that in June ;cation exchange capacity of differ-ent layers for Fraxinus velutina forest soil in October was higher than that in June ,and cation exchange capacity of 20 cm-depth for Elaeagnus angusti f olia forest soil in October was higher than that in June .It was concluded that the soil pH of Fraxinus velutina forest soil was lower than that of Elaeagnus angusti-f olia forest soil ,but soil organic matter ,available potassium content and cation exchange capacity were all higher than those of Elaeagnus angusti f olia forest soil ,and soil salt content was higher ;effect of im-provement of various soil chemical properties in October was better than that in June .