【作者】 刘杰；

【导师】 马履一； 贾忠奎；

【作者基本信息】 北京林业大学 ， 森林培育， 2013， 硕士

【摘要】 华北落叶松(Larix Princicpis-rupprechtii Mayr.)是我国华北地区主要的造林树种之一,特别是在冀北山区分布最广、蓄积量最大,是当地主要的目的树种之一。本研究通过对河北省塞罕坝机械林场阴河分场抚育间伐和修枝后18a、22a、38a华北落叶松人工林林下土壤理化性质、酶活性以及微生物数量等土壤质量指标的综合研究,分析比较不同抚育措施对林下土壤质量的影响,主要结论如下：(1)抚育后华北落叶松土壤物理性质作用不尽相同,但总体来说,除容重外,土壤含水量、毛管持水量和毛管孔隙度较对照有所增大,且随着土壤深度的增加而降低,各土层之间差异显著；不同间伐强度以中度和强度间伐最为明显,三个林龄之间除了容重差异显著外,其他差异不明显,以22a抚育效果最好。(2)抚育后华北落叶松林下土壤化学性质变化不尽相同,总体来看,pH值、全钾和速效磷含量较对照降低,全氮、有机质含量较对照增加,土层之间差异显著,不同林龄之间比较可以得出,38a土壤化学性质要优于其他两个林龄,除全钾外,林龄之间差异显著。(3)土壤多酚氧化酶活性较对照降低了8.88%～33.44%,随土层加深总体表现为降低的趋势,随季节的变化规律以5月活性最高,林龄之间进行比较以38a活性最高且与其他两个林龄存在显著差异；过氧化氢酶和脲酶活性增加,分别增加了6.22%～18.99%、2.30%～25.88%,均随着土层加深而增大,土层之间差异显著；随季节的变化为以9月过氧化氢酶和脲酶活性最大,分别高出5、7月2.07%～197.18%、47.47%～537.90%,差异极其显著,林龄之间均表现为22a＞18a＞38a,林龄之间差异显著。(4)土壤细菌和真菌数量较对照有所增加,分别增加了4.86%～27.08%、3.81%～44.54%,而放线菌数量较对照降低3.57%～49.99%,随季节的变化情况为,微生物数量均以7月最多,这主要是因为7月林下温度高,微生物活动频繁,不同月份之间差异显著。(5)运用主成分分析法评价抚育间伐效应,结果表明：18a、22a综合得分最大的分别为P0T3和P1T2,总体上经过抚育后华北落叶松人工林林下土壤质量得以提高,且随着修枝强度的增加而减少、间伐强度的增加而增大。38a不同间伐强度综合得分排序为T4>T3>T2>CK>T1,且随着间伐强度的增加而增大,经过抚育后38a华北落叶松人工林林下土壤质量得以提高；3种林龄华北落叶松抚育一年后其土壤质量综合得分以22a最高为0.244,其次为18a为0.199,得分最低是38a为-0.443,可以得出抚育后华北落叶松人工林林下土壤质量随着林龄的增加先增后减,以22a土壤质量最好,抚育效果最佳。更多还原

【Abstract】 Larix Princicpis-rupprechtii Mayr. is a main tree species for afforestation in North China. In mountainous areas of North Hebei Province, with a most wide distribution and a largest amount of living stock, Larix Princicpis-rupprechtii Mayr. is one of the important purpose species of trees in local area. In this study, after1year of thinning and pruning, the indicative factors of soil quality that include soil physical and chemical properties, enzyme activity, and quantity of microbes in18,22, and38years old stands were investigated and analyzed synthetically. The effects of different silvicultural measures on soil quality in Larix Princicpis-rupprechtii Mayr. were compared to get a suitable management. The main conclusions and results show as follow:(1) After management, in general, soil bulk density increased with the increasing of soil depth, but had a decrease compared to CK plots. Soil water content, capillary water holding capacity, and capillary porosity all increased than that in CK plots, and decreased in vertical gradient of soil. They differed significantly among each soil layer. Most indicative factors (except soil bulk density) did not have significant difference in18,22and38years old stands. The22years old stand got a best soil quality after management.(2)Soil chemical properties in Larix Princicpis-rupprechtii Mayr. stands varied to a large extent after forest management. Compared to CK plots, values of total potassium, available phosphorus and pH became lower. Total nitrogen and soil organic matters increased and differed in each soil layer. Soil chemical properties in38years old stand were better than that in18and22years old stands. All indicative factors of soil chemical properties except total potassium had significant differences among3stands.(3)Soil polyphenol oxidase activity, after thinning and pruning, declined by8.88%to33.44%of that in CK plots, and decreased with soil depth. Soil polyphenol oxidase activity peaked in May, and differed significantly in38years old stand with a maximum to other2stands. The activity of catalase and Urine enzyme increased separately by6.22%to18.99%and2.30%to25.88%than CK plots and both increased accompanying with the increase in vertical gradient of soil. The seasonal variation was that the peak values of catalase and urine enzyme, which greater respectively by2.07%to197.18%and47.47%to537.90%than that in May and July, appeared in September. The activity of catalase and Urine enzyme had significant difference in18,22and38years old stands.(4)After thinning and pruning, germ in soil increased by4.86%to27.08%and soil fungi increased by3.81%to44.54%than CK plots. Actinomycetes decreased by3.57%to49.99%than CK plots. The quantities of microbe had significant differences among different month. Microbe quantity peaked in July for a higher soil temperature.(5)Using principal component analysis (PCA) to access the thinning and pruning effect on soil quality, we found that the P0T3in18and P1T2in22years old stands. Generally soil quality improved after management. The heavier of pruning densities, the less improvement of soil quality. The heavier of thinning densities, the more improvement of soil quality. In38years old stand, the order of composite scores in plots of different thinning densities was:T4>T3>T2>CK>T1. After management, the composite scores of soil quality in22years old stand was a maximum of0.244,0.199in18years old stand and a minimum of-0.443in38years old stand. The results suggesting that at first the soil quality after management improved and then declined with increasing of stand age. Forest management had a optimal effect on soil quality in22years old stand.更多还原