Microbial activities in a histosol: Effects of wood ash and NPK fertilizers |
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Authors: | Assi Weber Marjut Karsisto Riika Leppänen Veronica Sundman J Skuji?? |
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Institution: | 1. Department of General Microbiology, University of Helsinki, Mannerheimintie 172, SF-00280 Helsinki 28, Finland;1. Finnish Forest Research Institute, Rillitie 10, SF-01370 Vantaa 37, Finland;2. Utah State University, Department of Biology and Ecology Center, Logan, UT 84322, U.S.A. |
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Abstract: | Mineralization of organic matter and microbial activities in an intensively cultivated acid, N-rich peat soil planted with Salix sp. cv. aquatica were examined for 3 yr. The soil was amended with wood ash or NPK fertilizers providing N as ammonium nitrate or urea. The wood ash amendment (10 tons ha?1) increased soil pH from 4.6 to 5.5 and increased markedly all microbial activities measured, resulting in increased mineralization and N availability, and in loss of 9% total soil N during the first year. The addition of ammonium nitrate caused a corresponding though less pronounced increase in N mineralization. Cellulose decomposition increased in all amended soils, reaching rates 53–86% higher than in non-amended soil. Potential N2 fixation (C2H2 reduction) by free-living organisms was increased by the ash-amendment. Potential denitrification rates were positively correlated (r = 0.98) with the presence of water-soluble organic-C, which was more abundant in ash-amended and non-amended soils than in the soils fertilized with N. |
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