| 摘要: |
| 【目的】以秦岭南坡锐齿栎林为研究对象，探讨间伐对锐齿栎林地土壤腐殖质及土壤微生物的影响，为秦岭林区锐齿栎林抚育经营提供理论依据。【方法】2012年3月，在秦岭南坡陕西省宁东林业局沙沟林场林地阳坡的中下部选择生长状况接近、林分密度基本一致的锐齿栎天然次生林，设置锐齿栎天然次生林样地12块，间伐强度分别为林分蓄积量的0（CK）、5%（T1）、10%（T2）、15%（T3）、20%（T4）和25%（T5），2018年7月采集0～30 cm土层土样，测定土壤腐殖质及其组分（胡敏酸、富啡酸和胡敏素）含量以及土壤微生物（细菌、真菌、放线菌）数量，并分析土壤胡敏酸、富啡酸和胡敏素含量与细菌、真菌、放线菌数量的相关性。【结果】（1）间伐6年后，在0～30 cm土层，各间伐强度处理土壤腐殖质含量平均值均大于CK，且T1处理的土壤腐殖质含量最高，为（60.78±10.53） g/kg。各间伐强度下土壤胡敏酸含量平均值较CK均有明显减少，不同处理土壤胡敏酸含量平均值由大到小依次为CK>T4>T3>T5>T2>T1。除T3处理外，其余间伐强度处理土壤富啡酸含量平均值均高于CK，富啡酸含量平均值由大到小依次为T2>T1>T5>T4>CK>T3。与CK相比，除T1处理外，其余各间伐强度处理土壤胡敏素含量平均值均增加，各间伐强度处理土壤胡敏素含量平均值由大到小依次为T2>T3>T4>T5>CK>T1。（2）不同间伐强度下土壤胡敏酸/腐殖酸含量比值（PQ）由大到小依次为CK>15%>20%>25%>10%>5%。(3)间伐6年后，在0～30 cm土层，土壤微生物总量随着间伐强度的增加呈先增加后减少的趋势，微生物总量在间伐强度为10%时达到最高；土壤细菌、放线菌数量在间伐强度为5%～10%时较高，真菌数量在间伐强度为15%～20%时较高。（4）土壤细菌、真菌和放线菌数量均与土壤胡敏酸、胡敏素含量呈极显著正相关，土壤真菌数量与富啡酸含量呈显著正相关。【结论】土壤微生物各种群数量可以显著影响土壤腐殖质的积累，合理的抚育间伐可以显著增加土壤腐殖质含量及微生物数量，选择10%～15%的间伐强度作为提高林地土壤腐殖质的参考指标较为合理。 |
| 关键词: 秦岭南坡 锐齿栎林 抚育间伐 土壤腐殖质 土壤微生物 |
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| 基金项目:林业公益性行业科研专项“秦岭天然次生公益林抚育经营关键技术研究”（201204502） |
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| Effects of thinning on soil humus and microbes in Quercus aliena var.acuteserrata forest on the southern slope of the Qinling Mountains |
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WANG Xianchu,DONG Pengfei,DANG Kunliang,et al
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| Abstract: |
| 【Objective】This study investigated effects of thinning on soil humus and soil microorganisms in Quercus aliena var.acuteserrata forest on the southern slope of the Qinling Mountains to provide basis for the tending and management of Quercus aliena var.acuteserrata forest.【Method】In March 2012,in the middle and lower parts of the sunny slope of Shagou Forest Farm,Ningdong Forestry Bureau,Shaanxi,on the southern slope of the Qinling Mountains,12 plots of natural secondary forest of Quercus aliena var.acuteserrata with similar growth status and stand density were set up.The thinning intensity was 0(CK),5% (T1),10% (T2),15% (T3),20% (T4) and 25% (T5),respectively.In July 2018,0-30 cm soil samples were collected to determine contents of humus and its components (humic acid,fulvic acid and humin) and numbers of soil microorganisms (bacteria,fungi and actinomycetes).The correlations between contents of humic acid,fulvic acid and humin and numbers of bacteria,fungi and actinomycetes were also analyzed.【Result】(1) Six years after thinning,the average content of humus in 0-30 cm soil layer was higher than CK in all treatments,and T1 had the highest content of (60.78+10.53) g/kg.The average humic acid content of soils under different thinning intensities was significantly lower than CK in the order of CK>T4>T3>T5>T2>T1.Except for T3 treatment,the average content of fulvic acid in other treatments was higher than CK with the order of T2>T1>T5>T4>CK>T3.Except for T1 treatment,the average humin content of all thinning intensity treatments increased in the order of T2>T3>T4>T5>CK>T1.(2) The ratio of humic acid to humic acid (PQ) in soil under different thinning intensities was in the order of CK>15%>20%>25%>10%>5%.(3) Six years after thinning,the numbers of soil microorganisms increased first and then decreased with the increase of thinning intensity.The number of microorganisms reached the highest when thinning intensity was 10%.The numbers of bacteria and actinomycetes were higher when thinning intensity was 5%-10%,and the number of fungi was higher when thinning intensity was 15%-20%.(4) The numbers of soil bacteria,fungi and actinomycetes were positively correlated with the contents of humic acid and humin,and the number of fungi was positively correlated with the content of fulvic acid.【Conclusion】The amounts of soil microbial communities can significantly affect the accumulation of soil humus.Reasonable thinning can significantly increase soil humus and microorganisms.The thinning intensity of 10%-15% is suggested for improving soil humus in forest land. |
| Key words: southern slope of the Qinling Mountains Quercus aliena var.acuteserrata forest tending thinning soil humus soil microorganism |
