不同植被对石漠化地区土壤微生物数量的影响

Effects of Different Vegetation on Soil Microbial Quantity in Karst Rocky Desertification Areas

通过对桂西北石漠化地区不同植被调查样地细菌、真菌、放线菌等不同土壤微生物类群数量的测定,及其与相应样地凋落物纤维素分解强度和土壤有机质、速效磷、全磷、碱解氮、全氮、速效钾、全钾等生态因子的相关性分析,了解不同植被对石漠化地区土壤质量变化的影响,以便筛选出石漠化地区生态恢复的优良先锋树种,为桂西北岩溶地区退化生态系统的恢复与重建提供科学依据.实验结果表明：（1）不同植被对土壤微生物的影响作用不同,各样地土壤有机质及氮磷钾含量有明显差异,不同类群土壤微生物数量差异显著,其大小排序为：细菌〉放线菌〉真菌,细菌、放线菌和真菌所占比例分别为50.82%～73.70%、23.90%～49.12%和0.05%～4.85%;（2）土壤微生物数量与凋落物纤维素分解强度及土壤氮、磷、钾含量显著相关;（3）综合考虑不同类群土壤微生物数量及土壤营养状况,以任豆、青檀、圆果化香、侧柏为优势种的样地,其土壤质量状况较好,而以湿地松、小叶桉、湿地松＋小叶桉、类芦为优势种的样地,其土壤质量状况较差,前者比较适合作为石漠化地区植被恢复的先锋树种,后者则应该谨慎使用或不宜使用.

In this paper, quantities of soil microbial, bacteria, antinomycetes and fungi of different vegeta- tion plots in karst rocky desertification area of northwest Guangxi are determined by dilution plate method, correla- tion between different ecological factors, such as litter cellulose decomposition intensity, contents of soil organic matter, available phosphorus, total phosphorus, alkali solution nitrogen, total nitrogen, available potassium, total potassium are analyzed to understand the influence of different vegetation on soil quality changes of karst rocky de- sertification area, so as to select the excellent pioneer tree species for ecological restoration of this area, and pro- vide scientific basis for rehabilitation of the degraded karst ecosystem of northwest Guangxi. The results show that the effects of different vegetation on soil microbial are different; contents of soil organic matter and soil nitrogen content, soil phosphorus content, soil potassium content have significant differences in different sites. The quanti- ties of different groups of soil microbial have significant difference. The order of the size is as follows： bacteria 〉 antinomycetes 〉 fungi. Bacteria, antinomycetes and fungi account for 50.82% ～ 73.70%, 23.90% ～ 49.12% and 0.05 % ～ 4.85 % of total numbers of the soil microbial respectively. There are significant correlations among soil microbial quantity and litter decomposition intensity and soil nitrogen, phosphorus and potassium content. Con- sidering different groups of soil microorganism quantity and soil nutrient status, in the sample sites where dominant species are Zenia imignis, Pteroceltis tatarinowii, Platycarya or Thuja ccidentalis , the soil quality is better while in the plots where dominant species are Pinus elliottii, Eucalyptus exserta, Pinus elliottii ＋ Eucalyptus exserta, Neyraudi reynaudiana, the soil quality is poorer. The former trees are suitable to serve as the pioneer tree species of vegetation restoration in karst rocky desertification area, and the latter should be cautious to use or should not be used.