大小兴安岭林区不同林型土壤养分综合评价

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

基于大小兴安岭地区主要林型野外采样数据,利用统计学方法分析了红松林、针阔混交林、白桦林、樟子松林和蒙古栎林土壤有机质、全氮、速效磷和速效钾的垂直分布特征,并对土壤养分状况进行了综合评价。结果表明,不同林型土壤(0—40cm)有机质、全氮、速效磷、速效钾养分含量差异显著。有机质、全氮、速效磷3种土壤养分的总体分布是白桦林、针阔混交林比较高,针叶林次之,蒙古栎林比较低;而速效钾含量以蒙古栎林、白桦林为最高,针阔混交林却比较低。用改进的内梅罗综合指数法进行综合评价,结果显示,大小兴安岭林区土壤有机质和全氮含量特别丰富,速效磷含量为中等至较丰富,不同林型土壤养分总体处于良偏优水平,但速效钾比较缺乏,成为该林区土壤质量的主要限制因素。

This study is based on the field data obtained for the main forest types in Xing＇an mountains re gion, 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 medi um to high level. The overall soil nutrient of the studied forests is in a relatively high level, but the content of avail- able potassium is in a low level. Lack of available potassium has become a major limitation in this area.