北京九龙山土壤质量综合评价

Comprehensive evaluation of soil quality fertility in Jiulong Mountain,Beijing

以北京九龙山13种林分类型的土壤为研究对象,选取6项土壤指标,基于非线性隶属度函数法确定各指标隶属度值,同时采用灰色关联法确定各指标权重,最终应用综合指数法和加权求和法对土壤质量进行综合评价。结果表明:(1)研究区土壤p H值普遍偏低,土壤养分含量分布不均。土壤养分不仅在林分之间差异较大,而且在同一林分中,表土层与其余土层之间差异也较大,并随着土层的加深逐渐下降;(2)有效磷和全氮是影响研究区土壤质量的限制性因子;(3)有机质和碱解氮的权重较大;(4)2种模型的土壤综合质量变化趋势一致,各土层土壤综合质量排在前2名的都是灌木林和白蜡林,而最低的则都是樟子松林,且所有林分表土层的综合质量远高于其它土层。研究区土壤综合质量总体偏低,大多处于中下水平,仅表土层较好。该研究可为该区域森林抚育及土壤可持续利用提供参考依据。

Based on soil data of 13 forest types in Jiulong Mountain, Beijing, 6 soil indicators were firstly selected, and then their membership values were calculated by non-linear membership functions, their weight coefficients were determined by grey association analysis method. Soil quality of different stands in Jiulong Mountain, Beijing was finally evaluated through integrated soil tertility indices model and additive fertility quality indices model. Results showed as follows： （ 1 ） pH was generally low and the soil nutrienl contents were disproportional in the tested area. Meanwhile, there was great ditt）rence of soil nutrient contents not only among forest types but also between the upper soil layer and other soil layers in the same stand, and the soil nutrient contents reduced gradually from the upper to lower soil layers. （2） Available phosphorus and total nitrogen were the key factors to affect the soil quality in the tested area. （3） The organic matter and alkali hydrolysable nitrogen had larger proportion in the weight coefficients. （4） The trends of soil quality calculated by two models were consistent. The top two of soil comprehensive quality were the shrubbery and Fraxinus chinercsis torest in all soil layers, whereas the lowest quality was the Pinus sylvestris vat. mongolica forest, and the soil comprehensive quality of the upper soil layer was far higher than other soil layers in all forest types. So the soil comprehensive quality was low and was mostly in the middle and lower levels, only the top soil quality was better. And this research can provide reference for the further forest tending and soil sustainable utilization in Jiulong Mountain, Beijing.