Effects of carbon and lime additions on mineralization of C and N in humus from cutovers of western red cedar–western hemlock forests on northern Vancouver Island
作者:
C.E. Prescott,
M.A. McDonald,
期刊:
Canadian Journal of Forest Research
(NRC Available online 1994)
卷期:
Volume 24,
issue 12
页码: 2432-2438
ISSN:0045-5067
年代: 1994
DOI:10.1139/x94-314
出版商: NRC Research Press
数据来源: NRC
摘要:
The potential for amendments of simple C compounds or lime to improve N availability in humus from cedar–hemlock cutovers was tested in laboratory incubations and a greenhouse bioassay. Rates of C and N mineralization in samples of humus and woody humus during aerobic incubations in the laboratory were not affected by additions of potato starch. Mineralization of C was stimulated and net N mineralization was reduced after glucose addition. Microorganisms in humus may not be capable of degrading starch, and simpler C sources such as glucose increase immobilization of N in microbial biomass. The biomass of seedlings of western red cedar (ThujaplicataDonn), western hemlock (Tsugaheterophylla(Raf.) Sarg.), and Sitka spruce (Piceasitchensis(Bong.) Carr.) grown in pots containing cedar–hemlock humus amended with dolomitic lime was similar to the biomass of seedlings grown in unamended humus after 18 months. Seedlings grown in humus amended with N and P fertilizers were significantly larger than those grown in unamended or lime-amended humus. It is unlikely that applications of C or lime to cedar–hemlock cutovers would increase rates of N mineralization from humus. Additions of nutrients appear to be the only practical means of alleviating the nutrient supply problems on these sites.
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