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  • 1
    Electronic Resource
    Electronic Resource
    Earthworms and enchytraeids in conventional and no-tillage agroecosystems: A biocide approach to assess their role in organic matter breakdown (1990)
    Springer
    Biology and fertility of soils 10 (1990), S. 1-10 
    Details
    ISSN: 1432-0789
    Keywords: Earthworm ; Enchytraeid ; Tillage ; Organic matter ; Biocide ; Agroecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Earthworm and enchytraeid densities and biomass were sampled over an 18-month period in conventional and no-tillage agroecosystems. Overall, earthworm densities and biomass in the no-till system were 70% greater than under conventional tilling, and enchytraeid densities and biomass in the no-till system were 50%–60% greater. To assess the role of annelids in the breakdown of soil organic matter, carbofuran was applied to field enclosures and target (earthworm and enchytraeid biomass, standing stocks of organic matter) and non-target effects (bacteria, fungi, protozoa, nematode and microarthropod densities, litter decay rates, plant biomass) were determined in two 10-month studies. In the winter-fall study, carbofuran reduced the annelid biomass, and total soil organic matter standing stocks were 47% greater under no-till with carbofuran compared to control enclosures. Twelve percent of the difference could have been due to non-target effects of carbofuran, as determined from litterbag decay rates. In the summer-spring study, carbofuran again significantly reduced the annelid biomass, and treated pens in the no-till area had significantly greater standing stocks of fine organic matter (43%–45%). Although the densities of bacteria and nematodes were reduced in carbofuran-treated litterbags under a no-till system, the rates of decay were not reduced and estimates of the amount of organic matter processed could not be adjusted for non-target effects. A 76% difference in the standing stock of coarse organic matter between control and carbofuran-treated pens in the conventional-till system indicated further non-target effects. We concluded that our estimates of the amount of organic matter processed by annelids in no-till and conventionally tilled agroecosystems represented a maximum potential because of the confounding non-target effects of carbofuran.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336117
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The distribution and abundance of soil nematodes in East African savannas (1991)
    Springer
    Biology and fertility of soils 12 (1991), S. 67-72 
    Details
    ISSN: 1432-0789
    Keywords: Nematodes ; Microbivores ; Savannas ; Detrital food webs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nematodes were sampled from sites under and between tree canopies in Tsavo National Park, Kenya. We tested the hypothesis that more nematodes would be present in the generally moister soil, under the canopy, with a larger biomass of green grass prevailing for many months of the year. We found that microbivorous nematodes comprised the bulk of the populations, approximately 90% of the total. Bacterivores were more numerous (approximately 3×105 on average) versus fungivores (approximately 5×104 on average) per m2, to 10 cm depth. All four trophic groups (plant parasites and omnivore/predators in addition to the microbivore groups mentioned above) were significantly higher under acacia than baobab in a drier site, but not significantly different under the two tree species in a wetter site. Only bacterivores were significantly different with respect to distance from the tree, with higher numbers associated with the higher microbial biomasses under the tree canopies. These higher microbial biomasses were reflected in 2.5 times more potentially mineralizable N under the tree canopies at the drier site. We suggest that belowground detrital and microbivorous food webs in savannas may be similar to those in temperate grasslands. Further proof of this idea awaits more extensive research.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00369390
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  • 3
    Electronic Resource
    Electronic Resource
    Soil biology, soil ecology, and global change (1992)
    Springer
    Biology and fertility of soils 14 (1992), S. 104-111 
    Details
    ISSN: 1432-0789
    Keywords: Global change ; Scaling ; Hierarchies ; Soil organisms ; Soil processes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This overview paper addresses aspects of scaling in space and time, and scaling in relation to micro-and macrohabitats. Ecological processes in soils are examined for possible generalizations about processes and organisms, across a wide range of different habitats. Problems of scaling in space and time that have an important impact on processes associated with global change are outlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336258
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Simulated acid rain effects on fine roots, ectomycorrhizae, microorganisms, and invertebrates in pine forests of the southern United States (1992)
    Springer
    Water, air & soil pollution 61 (1992), S. 269-278 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A 2-yr study evaluated the effects of acid precipitation on the forest floor community. Throughfall was collected at weekly intervals, acidified to pH 4.3 and 3.6, and applied to throughfall excluded 1 m2 plots in a stand of loblolly pine (Pinus taeda L.) in south Mississippi, and in a longleaf pine (P. palustris Mill.) plantation in east Texas. Control plots received ambient throughfall which ranged from pH 3.7 to 6.2 in Mississippi and pH 3.8 to 6.7 in Texas. Five plots of each treatment at each location were destructively sampled after 1 yr and the 5 remaining plots were sampled after 2 yr. Chemical analyses were conducted for all collections of throughfall and litter leachate, and for the fermentation layer, rhizosphere, and mineral soil. After 2 yr, comparisons of the pH 3.6 plots with the controls indicated significant decreases in the number, length and biomass of lateral roots, and the percent and number of ectomycorrhizae. Decreases in these root characteristics for plots subjected to applications of throughfall acidified to near-ambient pH 4.3 were also significant or bordered on significance. Numbers of herbivorous mites increased significantly with decreasing pH, but the predaceous mites appeared insensitive. Treated plots had fewer numbers of some groups of the larger invertebrates, especially earthworms, but variation was generally too great to show significance. The acid treatments had little effect on numbers of nematodes, saprophytic fungi or endomycorrhizal fungi.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00482610
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  • 5
    Electronic Resource
    Electronic Resource
    cDNA cloning and expression of aTalaromyces emersonii amylase encoding genetic determinant inEscherichia coli (1992)
    Springer
    Biotechnology letters 14 (1992), S. 1109-1114 
    Details
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Intact mRNA has been isolated from the thermophilic fungusTalaromyces emersonii following growth on starch containing media. This has been used as template to synthesise cDNA. The cDNA was cloned into theEscherichia coli expression vector system, pUC18 and this was used to transformE. coli. Transformed colonies were screened for production of amylase activity and a number of positive recombinants were detected. One of those was found to contain a plasmid named pMH1, which harboured a 1.2 kb insert. Sub-cloning experiments verified that the amylase phenotype was encoded for by this fragment. The fragment was characterised using restriction enzyme cleavage site analysis. The origin of the insert was verified using both Northem and Southem blotting hybridisation analysis ofT. emersonii RNA and DNA respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01027011
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