陕南秦巴山区厚朴群落土壤肥力评价

Soil fertility quality assessment of Magnolia officinalis communities in Qinba mountains

以秦巴山区7个厚朴群落为对象,分析土壤养分含量的变化规律,同时对各群落土壤肥力进行评价,以期为该区土壤肥力的提高和厚朴群落配置模式的筛选提供理论依据和实践指导。结果表明,秦巴山区厚朴群落间土壤养分含量差异显著;除全磷和全钾外,随土层深度的增加,土壤有机质、全氮、碱解氮、速效磷和速效钾含量逐渐减小。厚朴群落土壤肥力综合指数从大到小依次为:4a凹叶厚朴(1.054)>2a凹叶厚朴(0.882)>山茱萸-凹叶厚朴混交林(0.673)>7a尖叶厚朴(-0.243)>7a凹叶厚朴(-0.713)>杜仲-凹叶厚朴(-0.812)>11a凹叶厚朴(-0.840)。因此随着林龄的增大,厚朴群落土壤肥力有下降的趋势。结合厚朴群落土壤养分差异分析和厚朴群落土壤肥力评价结果,得出山茱萸-凹叶厚朴混交林的土壤肥力相对较好,为该区植被恢复的最佳营造模式。

Soil fertility is a reflection of the basic properties and essential features of the soil,and fertile soils can provide indispensable nutrients for plant growth. Soil nutrients are one of the most important parameters for the evaluation of soil fertility. Spatial orientation and distribution of soil nutrients directly affect the level of soil fertility and ecological restoration. Magnolia officinalis is a traditional medicinal tree species in China,and it is often used as the preferred tree on Qin-Ba Mountain. In order to clarify the distribution of soil nutrients and soil fertility status of different Magnolia officinalis communities on Qin-Ba Mountain,five communities were analyzed： 2-year-old,4-year-old,7-year-old,and 11-year-old Magnolia officinalis and 7-year-old Magnolia officinalis officinalis. Two other plant communities were also selected：Eucommia ulmoides-Magnolia officinalis and Macrocarpium officinale-Magnolia officinalis. The soil nutrients of the seven communities were determined using one-way analysis of variance,and the soil integrated fertility index of the seven communities was evaluated using the improved analytic hierarchy process. The results showed that the soil nutrients of the seven communities in the same soil layers were significantly different（ P 0. 05）. In addition,the parameters in different soil layers also differed remarkably. Soil organic matter,total N,available N,available P,and available K in the seven communities decreased with soil depth in the profile distribution; however,total P and total K did not show any specific characteristics. A comprehensive evaluation showed that the soil integrated fertility index of 4-year-old Magnolia officinalis was the highest（ 1. 054） among the seven communities,while that of 11-year-old Magnolia officinalis was the lowest（- 0. 840）. With the growth of plantations,soil fertility of Magnolia officinalis communities has declined. Soil fertility of Macrocarpium officinale-Magnolia officinalis（ 0. 673） was higher than that of 7-year-old Magnolia officinalis,whereas the soil fertility of Eucommia ulmoides-Magnolia officinalis（- 0. 812） was lower than that of 4-year-old Magnolia officinalis.Therefore,Macrocarpium officinale-Magnolia officinalis could improve soil fertility on Qin-Ba Mountain.