Search results for "soil biology"
showing 10 items of 109 documents
Effects of dimethoate and benomyl on soil organisms and soil processes – a microcosm study
1998
Abstract Effects of two pesticides, dimethoate, an insecticide, and benomyl, a fungicide, applied singly or together, on soil organisms and plant growth were studied in microcosms containing agricultural soil and indigenous soil fauna together with introduced invertebrates and barley. Dimethoate reduced soil microarthropod populations and the reduction was stronger in the upper than in the lower soil layer. The collembolan community structure was affected by both pesticides. Populations of microarthropods in pesticide-treated microcosms recovered during the experiment but the community structures remained differentiated. Total numbers of enchytraeids and nematodes were not affected by eithe…
Impacts of elevated CO2 and temperature on the soil fauna of boreal forests
2005
Abstract Responses of dominant soil decomposer animals in northern coniferous forests, enchytraeids and microarthropods, to elevated CO 2 concentration and temperature were studied by sampling an experiment consisting of closed field chambers with a ground area of 5.9 m 2 . Six species of enchytraieds were found in the study, with Cognettia sphagnetorum comprising 87% of all individuals. The treatments did not significantly affect the numbers of C. sphagnetorum . No treatment induced changes were found in oribatid mites, but numbers of acaridid mites were lowest in the chambers with elevated CO 2 concentration and in those with elevated temperature. The chambers had lower densities of actin…
Interactions between enchytraeid (Cognettia sphagnetorum), microarthropod and nematode populations in forest soil at different moistures
1998
Abstract Very little is known about the effects of microclimatic conditions on interactions within soil faunal communities. The aim of the experiment was to examine how the different functional components of the faunal community in coniferous forest soil affect each other at different moisture levels. Forest humus was defaunated by heating, adjusted to three water contents, distributed into glass jars and reinoculated with microflora and microfauna. Sets of 10 jars were inoculated with (1) Cognettia sphagnetorum, (2) Cognettia with Folsomia candida (Collembola), (3) Cognettia with a mixed community of microarthropods, (4) Folsomia alone, (5) mixed microarthropods alone, and (6) Cognettia wi…
Acute toxicity tests using earthworms to estimate ecological quality of compost and digestate
2017
Ecological quality of compost and digestate, used as fertilizers for agricultural use, was assessed through an acute ecotoxicological bioassay testing the earthworm Eisenia fetida (Annelida). The test evaluates the earthworm’s attitude to dig within 15 min into a soil medium constituted by a mixture of a standardized soil and different concentrations of compost/digestate. According to different classes of behavior responses, the sample is classified as good or bad quality (ON/OFF). The validity of this test was confirmed comparing the observations with the results from a standard chronic test developed by OECD (Organisation for Economic Co-operation and Development). Considering samples fro…
Effects of stump removal on soil decomposer communities in undisturbed patches of the forest floor
2011
Abstract Soil preparation after clear-cutting leads to fragmentation of forest floor and, consequently, changes the habitat of decomposers. Stump removal for bioenergy is further increasing the disturbance in the soil. We studied responses of decomposers to stump removal in boreal spruce forests during the first 4 years after clear felling in relation to mounding. Samples for each decomposer organism group were taken from undisturbed forest floor patches that are the main habitat for decomposers after forest regeneration and whose amount and size obviously differ between the treatments. Microbial biomasses and community structure, and the abundance of enchytraeids, were not found to be affe…
Dead-wood effects on enchytraeids and nematodes in thinned and unmanaged Norway spruce forests
2009
Abstract The effects of dead wood on enchytraeids and nematodes were studied in thinned and uncut Norway spruce forests in two experiments. Fifteen pairs of small spruce logs (one enclosed in polyethylene sheet and another untreated control) were returned to the forest floor in a complete randomized block design after thinning. Soil under the logs and at distances of 0–6 cm and 6–12 cm from each log was sampled after one growing season, and enchytraeids and nematodes were extracted and forest floor properties measured. Log enclosure increased enchytraeid length irrespective of the distance from the log. Soil moisture or pH were not affected by enclosure, but organic matter content was reduc…
Sensitivity of soil processes in northern forest soils: are management practices a threat?
2000
Abstract There is evidence that forest management practices influence soil-decomposer communities. It is also established that changes in the trophic structure and composition of these communities can induce changes in soil-nutrient dynamics, thereby affecting plant growth. Whether forest productivity is affected by management-induced changes in, e.g. soil faunal structure, is, however, yet to be shown. The aim of this study was (1) to determine the resolution of the ecological hierarchy (e.g. species, functional groups, trophic levels) at which a change in soil fauna would alter biotically-controlled processes in soils, and (2) to examine the sensitivity of soil fauna of the boreal forest …
Habitat patchiness affects decomposition and faunal diversity: a microcosm experiment on forest floor.
1998
Environmental heterogeneity has been intensively studied, but little is known about relationships between habitat patchiness and soil processes. The aim of this study was to investigate (1) the impact of patchiness of the litter layer on the decomposer community and litter decomposition rate, and (2) whether the impact of soil fauna on the rates of processes differs in relation to patchiness. An experiment was carried out in microcosms with coniferous forest humus and four kinds of litter with different C:N ratios or stages of decomposition, either separately (i.e. in patches) or mixed with each other. Microarthropod species diversity was better maintained in the patchy systems. In the abse…
Short-term responses of soil decomposer and vegetation communities to stump harvesting in boreal forests
2011
Recently, in addition to logging residues, stumps have become an important component in energy production since there is growing global interest in the use of renewable energy sources in order to decrease anthropogenic carbon emissions. Harvesting of stumps influences the forest floor by changing vegetation and soil organic layers and exposing mineral soil across large areas. We studied whether stump harvesting after clear felling poses further short-term changes in boreal forest soil decomposer community (microbes and mesofauna) and vegetation when compared to the traditional site preparation practice (mounding). In general, stump harvesting caused decline in enchytraeid abundance but did …
Laboratory design to simulate complexity of forest floor for studying the role of fauna in the soil processes
1990
We developed a technique for simulating the complexity of the soil system under controlled laboratory conditions. Removable microcosms were inserted in a homogeneous substrate soil in a large plastic box. This macrocosm was sealed, except for an inlet and outlet for air flow, and an aperture for collecting leachates. The system can be designed and manipulated in various ways according to the needs of a particular experiment. Respiration and nutrient fluxes can be measured either from the whole macrocosm or separately from the microcosms. We have performed three experiments in order to evaluate the role of animals in the soil processes. A set of macrocosms was constructed from components of …