不同生态地理区域杉木人工林土壤微生物及生化活性的研究

 本文研究了广西龙胜县里骆林区、宜山县庆远林区、岑溪县七坪林区和田林县老山林区四种不同生态地理区域杉木人工林土壤微生物及其生化活性。研究结果表明：1．土壤微生物的总数及各类群数量均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最高,岑溪县七坪林区次之,宜山县庆远林区最低。2．土壤生化活性包括土壤氮的转化强度,土壤碳的氧化代谢能力和土壤酶活性,也均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最强,岑溪县七坪林区次之,宜山县庆远林区最弱。3．四种不同生态地理区域杉木人工林生长状况与土壤微生物的数量分布和生化活性表现相似规律,龙胜县里骆林区和田林县老山林区杉木人工林林木生长最好,岑溪县七坪林区次之,宜山县庆远林区最差。     

广西杉木人工林土壤微生物及生化特性的研究

本文对桂北龙胜里骆林区、桂中宜山庆远林区、桂南岭溪七坪林区和桂西田林老山林区以及龙胜县里骆林区不同立地杉木人工林土壤微生物及其生化特性的研究结果表明:1、四地杉木人工林土壤微生物的数量以龙胜里骆林区和田林老山林区土壤最高,岭溪七坪林区次之,宜山庆远林区最低。2、四地区杉木人工林土壤生化活性也以龙胜里骆林区和田林老山林区土壤最强,岭溪七坪林区次之,宜山庆远林区最弱。3、龙胜里骆林区不同立地杉木人工林土壤微生物数量以山洼和黑砂土土壤最多,山坡次之,山脊、红土和黄土较少。生化活性也以山洼、山坡和黑砂土土壤较强,山脊、红土和黄土较弱。但海与拔不相关。     

Potential role of allelopathy in the soil and the decomposing root of Chinese-fir replant woodland

The role of allelopathy in the Chinese-fir (Cunninghamia lanceolata) replant problem was studied. The failure of Chinese-fir seedlings to grow normally in Chinese-fir replant woodland was not only caused by the depletion of nutrients and the deterioration of the structure of replant woodland soil, but also by biotic factors and allelopathy. Extracts of soils collected from replant woodlands significantly reduced the growth of Chinese-fir seedlings. Extracts and decomposing root residues also significantly inhibited the growth of Chinese-fir seedlings. Extracts of the replant soil and of the decomposing roots from Chinese-fir replant woodland were both toxic to other plants. The combination of the decomposing root residues and the pathogenic fungi reduced the growth of Chinese-fir seedlings the most when compared to the decomposing root residue alone and the control. It appears that allelopathy is at least partly involved in the Chinese-fir replant problem. ei]Section editor: R Rodriguez-Kabana     

连栽杉木林的根系研究

 本文通过对福建三明连栽杉木林的根系进行了调查研究。结果表明：连栽林地上的根系重量、组成、形态和分布发生较大的差异,第一代杉木林地的单株根量分别比第二代、第三代高出24.93%、49.69%,全林分别为31.93%、55.22%;第一代的杉木林根系的组成和分布较合理,营养空间大,利于杉木的生长发育。