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  • Canadian Science Publishing  (3)
  • Blackwell Science Ltd
  • 2005-2009  (5)
  • 1965-1969
  • 1945-1949
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 56 (2005), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Fires in boreal forests frequently convert organic matter in the organic layer to black carbon, but we know little of how changing fire frequency alters the amount, composition and distribution of black carbon and organic matter within soils, or affects podzolization. We compared black carbon and organic matter (organic carbon and nitrogen) in soils of three Siberian Scots pine forests with frequent, moderately frequent and infrequent fires.Black carbon did not significantly contribute to the storage of organic matter, most likely because it is consumed by intense fires. We found 99% of black carbon in the organic layer; maximum stocks were 72 g m−2. Less intense fires consumed only parts of the organic layer and converted some organic matter to black carbon (〉 5 g m−2), whereas more intense fires consumed almost the entire organic layer. In the upper 0.25 m of the mineral soil, black carbon stocks were 0.1 g m−2 in the infrequent fire regime.After fire, organic carbon and nitrogen in the organic layer accumulated with an estimated rate of 14.4 g C m−2 year−1 or 0.241 g N m−2 year−1. Maximum stocks 140 years after fire were 2190 g organic C m−2 and 40 g N m−2, with no differences among fire regimes. With increasing fire frequency, stocks of organic carbon increased from 600 to 1100 g m−2 (0–0.25 m). Stocks of nitrogen in the mineral soil were similar among the regimes (0.04 g m−2). We found that greater intensities of fire reduce amounts of organic matter in the organic layer but that the greater frequencies may slightly increase amounts in the mineral soil.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK; Malden, USA : Blackwell Science Ltd
    European journal of soil science 56 (2005), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Soils and sediments contain only small amounts of organic matter, and large concentrations of paramagnetic metals can give poor solid-state nuclear magnetic resonance (NMR) spectra of organic matter. Pretreatment of samples with hydrofluoric acid (HF) dissolves significant proportions of the mineral matrix and extracts paramagnetic elements. We investigated the effects of 10% HF treatment on the stable isotope content of carbon (C) and nitrogen (N) of organic matter from soils, composts and shales. Additionally we inferred molecular and isotopic characteristics of lost materials from calculations of isotope mass balances. Treatment with HF enriched C and N in mineral samples substantially (factors 2.5–42.4), except for Podzol B horizons (1.1–1.7) and organic material (1.0–1.3). After treatment most of the C (59.7–91.7%) and N (53.7–86.6%) was recovered, although changing C/N ratios often indicated a preferential loss of N-rich material. Isotope ratios of C and N in the remaining material became more negative when net alterations exceeded 0.3‰. The isotope ratios of the lost material contained more 13C (1–2‰) and 15N (1–4‰) than the initial organic matter. Acid hydrolysis typically removes proteins, amino acids and polysaccharides, all of which are enriched in 13C, and in the case of proteins and amino acids, enriched in 15N as well. We conclude that HF treatment released fresh, soluble, probably microbial, biomass in addition to carbohydrates. Net changes of the bulk chemical composition of organic matter were small for most soils, size fractions and plant material, but not for samples containing little organic matter, or those rich in easily soluble organic matter associated with iron oxides, such as Podzol B horizons.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2005-08-01
    Description: Mechanical site preparation (MSP) changes the distribution and character of forest floor and mineral soil and may affect soil nutrient availability, soil water content, and soil temperature. The effects of different kinds of MSP were compared to a control in the tenth growing season at two research sites in northern British Columbia. To compare MSP results with those of the natural disturbance regime, a burned windrow treatment was also included in the analysis. The bedding plow, fire, and madge treatments all had significantly greater crop-tree growth compared to the control. The bedding plow and madge treatments had significantly lower soil bulk density, higher soil temperature, and lower soil water throughout the growing season compared with that of the control. The bedding plow also resulted in significantly higher concentrations of total carbon, total nitrogen, NH4+, and NO3than that of the control, at both the 010 and 1020 cm depths. The madge rotoclear resulted in significantly greater potential mineralizable N than that of the control. Ionic resins bags, installed for one growing season, did not show any significant treatment differences in available soil nitrogen. MSP did not reduce soil fertility on these sites when compared with an untreated control, but it is difficult to say that it improved it.
    Print ISSN: 0045-5067
    Electronic ISSN: 1208-6037
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 4
    Publication Date: 2005-11-01
    Description: Forest landings are areas located adjacent to haul roads where harvested trees that were skidded from the cutblock are processed and loaded onto trucks. Soils on landings are often excessively compacted by heavy timber harvesting machinery and may take many years to recover from such disturbance. This study examined soil properties and tree growth on unrehabilitated landings (with and without natural regeneration) and adjacent naturally regenerated clearcuts in the central interior of British Columbia (BC), 23 yr after landing construction. Landings (both with and without natural regeneration) had less favorable conditions for tree growth than did clearcuts, including significantly greater surface soil bulk density and mechanical resistance (on some dates) and lower total porosity and concentrations of C and N. Landings without natural regeneration had the least favorable soil conditions, which may account for the lack of natural regeneration. Lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) growing on portions of the landings did not differ in height from those growing in adjacent clearcuts. Site index, as estimated using the growth intercept method, did not differ between naturally regenerated landings (21.7 m) and clearcuts (22.0 m), suggesting that the soils may be equally capable of supporting productive forests. Key words: Forest soil disturbance, soil mechanical resistance, soil productivity, soil water content, natural regeneration
    Print ISSN: 0008-4271
    Electronic ISSN: 1918-1841
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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  • 5
    Publication Date: 2008-05-02
    Description: This study was aimed at detecting the spatial characteristics of forest floor properties and litterfall amounts related to bigleaf maple (Acer macrophyllum Pursh) within conifer forest. Two 36-m × 36-m plots, centered on individual dominant bigleaf maple stems, were sampled at 129 systematic locations and tested for forest floor pH, cation exchange capacity, exchangeable cations, and mineralizable N. Tree stem location, forest floor horizon depths and litterfall amounts were measured. The kriging approach was used to visualize overall spatial patterns, Moran's I was used to give a global measure of spatial autocorrelation over the sampled region, and local indicators of spatial association (LISA) was used to detect and locate significant spatial clustering of similar values at the local scale. Most soil chemical properties had higher values in locations adjacent to the bigleaf maple stem, up to distances of 2.5 m from the stem on both study plots, and all exchangeable cations were positively spatially autocorrelated (P 〈 0.05) up to distances of 4 m. The majority of bigleaf maple litter (84% on plot 1, 92% on plot 2) was found to be deposited directly beneath the canopy extent. This study provides an understanding of the underlying spatial patterns of bigleaf maple influence on soil properties at plot scale. Key words: Bigleaf maple, spatial analysis, broadleaf species, plant-soil interactions local indicators of spatial association, forest floor
    Print ISSN: 0008-4271
    Electronic ISSN: 1918-1841
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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