Evaluation of Soil Nutrients for Different Forest Types in Xing′an Mountains Forest Area

This study is based on the field data obtained for the main forest types in Xing′an mountains region,including coniferous forest,mixed forest,birch forest,pine forest and Mongolian oak forest.By using statistical method,the vertical distribution characteristics of soil organic matter,total nitrogen,available phosphorus and potassium are analyzed and the soil nutrient status is evaluated.Results indicate that the contents of soil organic matter,total nitrogen,available phosphorus and potassium are different significantly among various forest soil(0—40 cm) types.The contents of organic matter,total nitrogen and available phosphorus in the soils of birch forest and mixed forest are the highest,followed by that in coniferous forest and then Mongolian oak forest.The available potassium content in soils of the Mongolian oak forest and birch forest is the highest and in the mixed forest,the lowest.The improved Nemerow comprehensive index is used to evaluate soil quality.The results show that the contents of organic matter and total nitrogen are especially abundant in Xing′an Mountain forest soils,and the content of available phosphorus is in the medium to high level.The overall soil nutrient of the studied forests is in a relatively high level,but the content of available potassium is in a low level.Lack of available potassium has become a major limitation in this area.