Subjects: Biology >> Ecology submitted time 2018-06-09 Cooperative journals: 《生态学报》
Abstract：为探讨黄河三角洲刺槐白蜡混交对土壤细菌群落结构及多样性的影响，通过高通量测序技术分析比较了刺槐白蜡混交林及刺槐纯林、白蜡纯林土壤细菌群落结构及多样性。结果表明：①混交林与两种纯林土壤细菌群落共36门。酸杆菌门、变形菌门、放线菌门（相对丰度大于10%）为刺槐白蜡混交林与两种纯林土壤中共有的优势菌群；硝化螺旋菌门为刺槐纯林土壤中的优势菌群。不同人工林土壤中各门细菌相对丰度差异显著。②混交改变了土壤细菌群落结构，提高了细菌多样性。刺槐白蜡混交林土壤细菌物种数、Chao1指数、Shannon指数分别为1934.5、2629.1、9.1，显著高于两种纯林。③相关性分析表明，土壤含水量与放线菌门细菌呈显著正相关；pH与芽单胞菌门细菌呈极显著正相关，与酸杆菌门细菌呈显著负相关。细菌多样性与土壤含水量呈显著正相关，与速效钾、有机质含量呈显著负相关。研究表明，刺槐白蜡混交林土壤细菌群落结构与两种纯林之间有一定差异，多样性差异显著，刺槐白蜡混交改变细菌群落结构，提高细菌多样性。
Subjects: Biology >> Ecology submitted time 2017-11-29 Cooperative journals: 《中国生态农业学报》
Abstract： To determine the distribution of fine roots of Robinia pseudoacacia mixed forests and pure forest in saline-alkali soils of Yellow River Delta, fine root distributions in Fraxinus velutina and Robinia pseudoacacia mixed forest, Ailanthus altissima and Robinia pseudoacacia mixed forest and Robinia pseudoacacia pure forest were sampled with a soil column method. The vertical distributions of fine roots in different forest stands were analyzed for the distributions of fine root biomass density, fine root surface area density, volume density, root length density and other root parameters. The aim of the study was to clarify differences of roots distribution of different forests and their relationship with soil properties and to provide references for the vegetation recovery and tree species selection in saline soils of the Yellow River Delta. The results showed that fine root biomass, surface area, volume and root length of F. velutina and R. pseudoacacia mixed forest were significantly higher than those of A. altissima and R. pseudoacacia mixed forest and R. pseudoacacia plantations. About 95.77% of fine root biomass of F. velutina and R. pseudoacacia mixed forest was distributed in the 0–60 cm soil layer, 85.37% in the 0–40 cm soil layer for A. altissima and R. pseudoacacia mixed forest and 66.38% in the 0–40 cm soil layer of Robinia pseudoacacia pure forest. Although surface aggregation of fine roots was conducive to reducing the harmful effects of saline-alkaline conditions on the root, fine roots of R. pseudoacacia pure forest were more uniformly distributed in the soil. F. velutina and R. pseudoacacia mixed forest had the highest total fine root biomass (91.56 g in 2500 cm2 of soil), significantly higher than those of other trees stands. Fine root surface area, length and volume densities of F. velutina and R. pseudoacacia mixed forest were significantly higher than that of R. pseudoacacia pure forest. Fine root tips of F. velutina and R. pseudoacacia mixed forest and A. altissima and R. pseudoacacia mixed forest were respectively 2.34 and 1.23 times that of R. pseudoacacia pure forest. Root forks of F. velutina and R. pseudoacacia mixed forest and A. altissima and R. pseudoacacia mixed forest were respectively 6.15 and 1.66 times that of R. pseudoacacia pure forest. There was a significant positive correlation between stand fine root biomass with soil available phosphorus and soil available potassium contents. The correlation between fine root biomass with available nitrogen and organic matter content of F. velutina and R. pseudoacacia mixed forest was also very significant and positive. The research showed that some mixed patterns increased fine root biomass distribution and the ability of roots to absorb soil nutrient. This suggested that proper mixing patterns could increase the adaptability of tree plantations.
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