黄土丘陵沟壑区欧李栽植对土壤质量改良作用的评价

黄土丘陵沟壑区生态恢复过程中植被的选择至关重要。近年来,欧李已在黄土丘陵沟壑区的植被恢复中被利用,但其生态作用有待系统评价。本试验选取山西省柳林县留誉镇黄土丘陵沟壑区内通过水平阶整地栽植的5 年生欧李灌丛地作为试验样地,并与相同栽培条件下的5年生油松林地进行对比,通过欧李根际与非根际、欧李灌丛下与欧李灌丛行间相同土层及欧李灌丛下与油松林下相同土层、层间土样差异分析,探究黄土丘陵沟壑区欧李种植后土壤养分与酶活性特征,并通过主成分分析对土壤质量做出综合评价,以便为欧李作为生态恢复树种提供理论依据。研究表明,1)与欧李行间土壤相比,欧李灌丛下土壤pH与土壤养分(除速效磷)、土壤酶活性(除20~40 cm土层过氧化氢酶)均得到不同程度改善;2)欧李灌丛下与油松林下土壤各具优势,欧李灌丛下土壤在碱解氮、全磷含量及酶活性方面优于油松林下,而在土壤含水量、电导率及其他养分含量方面次于油松林下;3)主成分分析得出,引起土样间差异的关键因子依次为:蔗糖酶、有机质、pH、全磷、碱解氮、碱性磷酸酶、速效磷;第一主成分得分从高到低依次为:欧李灌丛下0~20 cm土层>油松林下0~20 cm土层>欧李灌丛下20~40 cm土层>欧李行间0~20 cm土层>油松林下20~40 cm土层>欧李行间20~40 cm土层。综上所述,欧李种植使丘陵沟壑区土壤综合质量得到显著的提升。

Improvement of soil quality by Chinese dwarf cherry cultivation in the Loess Plateau steep hill region

In the process of ecological restoration in the Loess Plateau hilly gully region,selection of species for planting is important.Recently,Chinese dwarf cherry (Cerasus hum ilis) has been used for vegetation restoration in this region,but its ecological impact needs to be systematically evaluated.In this study,5-year-old plantings of Chinese dwarf cherry and Chinese pine (Pinus tabulaeformis) on level terraces near Liuyu town in Liulin county,Shanxi province,in the steep hill region of the Loess Plateau were compared.Soil samples were collected from 20 and 40 cm depth under the canopy of Chinese dwarf cherry bushes (UCC20,UCC40) and from the same soil depths at inter-row sites (IRC20,IRC40),and corresponding samples were collected from P.tabulaeformis plantations (designated UCP20 & UCP40),to compare the effects of the two plant species on soil properties.It was found that:1) compared with inter-row soil in Chinese dwarf cherry (IRC20 and IRC40),the pH values,nutrient contents (except available phosphorus) and enzyme activity values (except catalase activity for UCC40) were improved to differing degrees;2) planting with Chinese dwarf cherry (C) or pine (P) each had their own respective advantages.Alkali-hydrolysable nitrogen,total phosphorus content and enzyme activities of soil under the canopy of C (UCC20 and UCC40) were superior to those of P plantations (UCP20 and UCP40),while soil water content,electrical conductivity and other nutrient levels under the canopy of C were reduced compared to those under P.Results of a principal component analysis indicated that key factors for differentiation between different soil samples were,in descending order,invertase activity,organic matter content,pH value,total phosphorus,alkali-hydrolysable nitrogen and alkaline phosphatase activity.Mean scores for principal component 1 ranked in descending order:UCC20,UCP20,UCC40,IRC20,UCP40 and IRC40.In summary,the cultivation of Chinese dwarf cherry significantly enhanced comprehensive soil quality of the Loess Plateau steep hill region.