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  • 1
    Electronic Resource
    Electronic Resource
    Clear-cutting of a Norway spruce stand: implications for controls on the dynamics of dissolved organic matter in the forest floor (2004)
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 55 (2004), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Clear-cutting of forest provides a unique opportunity to study the response of dynamic controls on dissolved organic matter. We examined differences in concentrations, fluxes and properties of dissolved organic matter from a control and a clear-cut stand to reveal controlling factors on its dynamics. We measured dissolved organic C and N concentrations and fluxes in the Oi, Oe and Oa horizons of a Norway spruce stand and an adjacent clear-cutting over 3 years. Aromaticity and complexity of organic molecules were determined by UV and fluorescence spectroscopy, and we measured δ13C ratios over 1 year.Annual fluxes of dissolved organic C and N remained unchanged in the thin Oi horizon (∼ 260 kg C ha−1, ∼ 8.5 kg N ha−1), despite the large reduction in fresh organic matter inputs after clear-cutting. We conclude that production of dissolved organic matter is not limited by lack of resource. Gross fluxes of dissolved organic C and N increased by about 60% in the Oe and 40% in the Oa horizon upon clear-cutting. Increasing organic C and N concentrations and increasing water fluxes resulted in 380 kg C ha−1 year−1 and 10.5 kg N ha−1 year−1 entering the mineral soil of the clear-cut plots. We found numerous indications that the greater microbial activity induced by an increased temperature of 1.5°C in the forest floor is the major factor controlling the enhanced production of dissolved organic matter. Increasing aromaticity and complexity of organic molecules and depletion of 13C pointed to an accelerated processing of more strongly decomposed parts of the forest floor resulting in increased release of lignin-derived molecules after clear-cutting. The largest net fluxes of dissolved organic C and N were in the Oi horizon, yet dissolved organic matter sampled in the Oa horizon did not originate mainly from the Oi horizon. Largest gross fluxes in the Oa horizon (control 282 kg C ha−1) and increased aromaticity and complexity of the molecules with increasing depth suggested that dissolved organic matter was derived mainly from decomposition, transformation and leaching of more decomposed material of the forest floor. Our results imply that clear-cutting releases additional dissolved organic matter which is sequestered in the mineral soil where it has greater resistance to microbial decay.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1351-0754.2004.00609.x
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  • 2
    Electronic Resource
    Electronic Resource
    Soil organic matter quantity and quality in mountain soils of the Alay Range, Kyrgyzia, affected by land use change (2000)
    Springer
    Biology and fertility of soils 31 (2000), S. 407-413 
    Details
    ISSN: 1432-0789
    Keywords: Key words Soil organic matter ; Mountain soils ; Land use ; Deforestation ; Soil management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Changes in soil management practices influence the amount, quality and turnover of soil organic matter (SOM). Our objective was to study the effects of deforestation followed by pasture establishment on SOM quantity, quality and turnover in mountain soils of the Sui Checti valley in the Alay Range, Kyrgyzia. This objective was approached by analysis of total organic C (TOC), N, lignin-derived phenols, and neutral sugars in soil samples and primary particle-size soil fractions. Pasture installation led to a loss of about 30% TOC compared with the native Juniperus turkestanica forests. The pasture soils accumulated about 20% N, due to inputs via animal excrement. A change in land use from forest to pasture mainly affected the SOM bound to the silt fraction; there was more microbial decomposition in the pasture than in the forest silt fraction, as indicated by lower yields of lignin and carbohydrates, and also by a more advanced oxidative lignin side-chain oxidation and higher values of plant : microbial sugar ratios. The ratio of arabinose : xylose was indicative of the removal of carbohydrates when the original forest was replaced by pasture, and we conclude that this can be used as an indicator of deforestation. The accumulation of lignin and its low humification within the forest floor could be due to the extremely cold winter and dry summer climate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003749900187
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of deforestation on phosphorus pools in mountain soils of the Alay Range, Khyrgyzia (2000)
    Springer
    Biology and fertility of soils 31 (2000), S. 134-142 
    Details
    ISSN: 1432-0789
    Keywords: Key words Effects of deforestation ; Mountain soil ; Particle-size fractionation ; Phosphorus fractionation ; Phosphorus pools
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  The amount, quality and turnover of soil P is heavily influenced by changes in soil management. The objective of this study was to investigate the effects of deforestation and pasture establishment on the concentrations, forms and turnover rate of soil P in mountain soils of the Alay Range, Khyrgyzia. A sequential extraction was applied to distinguish soil P pools. We used particle-size fractionation to follow the dynamics of different P pools in soils under forest and pasture and 31P-NMR spectroscopy to investigate the structure of alkali-soluble P forms. In the A horizons of the forest soils, total soil P concentration was 1093 mg kg–1, organic P (Po) representing 46% of the total P. Deforestation followed by pasture establishment not only increased significantly (P〈0.01) the total P concentration (1560 mg kg–1) but also the contribution of Po to total P was increased by 17%. Pasture soils had significantly higher P pools than forest soils except highly labile inorganic P (Pi NaHCO3) and primary Pi (Pi HCldil). Both in forest and pasture soils stable P increased with decreasing particle size (coarse sand 50%, clay 80% of total P) and primary P decreased with decreasing particle size. Phosphate monoesters and diesters represented 80% of P identified by 31P NMR. Low monoester to diester ratios in the alkali extracts of forest and pasture soils indicate low microbial activity. This is consistent with high C/Po ratios and high stable Po concentrations in the fine earth of forest and pasture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050636
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