AUTHOR=Wang Liyan , Sun Yangyang , Li Jing , Tigabu Mulualem , Xu Qingli , Ma Xiangqing , Li Ming 

TITLE=Rhizosphere soil nutrients and bacterial community diversity of four broad-leaved trees planted under Chinese fir stands with different stocking density levels

JOURNAL=Frontiers in Forests and Global Change

VOLUME=6

YEAR=2023

URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2023.1135692

DOI=10.3389/ffgc.2023.1135692

ISSN=2624-893X

ABSTRACT=<sec><title>Objective</title><p>Rhizosphere soil nutrients and bacterial diversity of four broad-leaved tree species underplanted in Chinese fir plantation with different stand density levels were analyzed to reveal characteristics of the rhizosphere soil environment and selection of suitable underplanted tree species.</p></sec><sec><title>Methods</title><p>Chinese fir plantation with three density levels (900, 1,200, and 1,875 stems ha<sup>–1</sup>, respectively) were selected and underplanted with <italic>Michelia macclurei</italic>, <italic>Schima superba</italic>, <italic>Phoebe zhennan</italic>, and <italic>Tsoongiodendron odorum</italic>. The rhizosphere soil nutrients and bacterial community of the broad-leaved tree species were determined after 4 years.</p></sec><sec><title>Results</title><p>Significant differences in rhizosphere nutrient content were detected among different tree density levels, where the contents of total K, available K and available P in 900 stems ha<sup>–1</sup> stands were significantly higher than the other stocking density levels. There were also significant differences in the contents of total C, total N, total K, available K and available P in the rhizosphere soils of the four trees species, while there were no significant differences in pH and total P. Rhizosphere soil nutrient contents were higher under <italic>S. superba</italic> and <italic>M. macclurei</italic> than under <italic>P. zhennan</italic> and <italic>T. odorum</italic>. The rhizosphere soil nutrient contents and bacterial diversity decreased with the increase of stand density, and the bacterial diversity showed significant differences in the rhizosphere soils of <italic>P. zhennan</italic>, <italic>T. odorum</italic> and <italic>S. superba</italic> when underplanted in different stand densities. The bacterial diversity was positively correlated with the available P content of rhizosphere soils, suggesting that soil available P content plays an important role in shaping the structure of bacterial community.</p></sec><sec><title>Conclusion</title><p>The nutrient contents and bacterial diversity of rhizosphere soils of underplated broad-leaved species decreased with increasing stand density of Chinese fir plantation. Rhizosphere soils of <italic>M. macclurei</italic> and <italic>S. superba</italic> were rich in nutrient contents and bacterial diversity. Thus, low density of Chinese fir plantation (900 stems ha<sup>–1</sup>) underplanted with <italic>M. macclurei</italic> and <italic>S. superba</italic> is suitable for the establishment of mixed forest, which will facilitate better tree growth and maintaining soil fertility to realize sustainable management of forests.</p></sec>