نتایج جستجو برای: forest soils

تعداد نتایج: 150689  

Journal: :Applied and environmental microbiology 2001
K Cullings S Makhija

Molecular methods and comparisons of fruiting patterns (i.e., presence or absence of fungal fruiting bodies in different soil types) were used to determine ectomycorrhizal (EM) associates of Pinus contorta in soils associated with a thermal soil classified as ultra-acidic to extremely acidic (pH 2 to 4). EM were sampled by obtaining 36 soil cores from six paired plots (three cores each) of both...

2010
Laurel A. Kluber Kathryn M. Tinnesand Bruce A. Caldwell Susie M. Dunham Rockie R. Yarwood Peter J. Bottomley David D. Myrold

Dense hyphal mats formed by ectomycorrhizal (EcM) fungi are prominent features in Douglas-fir forest ecosystems, and have been estimated to cover up to 40% of the soil surface in some forest stands. Two morphotypes of EcM mats have been previously described: rhizomorphic mats, which have thick hyphal rhizomorphs and are found primarily in the organic horizon, and hydrophobic mats, which occur i...

2017
Raimund Prinz

Background Soil-background values of PCDD/F concentrations are usually conveniently displayed as toxic equivalent (TEq), being a bulk parameter of all relevant 7 PCDD- and 10 PCDF-congeneres, chloro-subsidized at the 2nd, 3rd, 7th and 8th carbon atom. Data here are ample, not so survey on congenere/homologue patterns occurring in soils. The sufficient number of samples taken within this analysi...

Journal: :Applied and environmental microbiology 2006
Santosh R Mohanty Paul L E Bodelier Virgilio Floris Ralf Conrad

The impact of environmental perturbation (e.g., nitrogenous fertilizers) on the dynamics of methane fluxes from soils and wetland systems is poorly understood. Results of fertilizer studies are often contradictory, even within similar ecosystems. In the present study the hypothesis of whether these contradictory results may be explained by the composition of the methane-consuming microbial comm...

2001
Jirí Kopácek Josef Veselý Evzen Stuchlík

Major fluxes of sulphur and dissolved inorganic nitrogen were estimated in Central European mountain ecosystems of the Bohemian Forest (forest lakes) and Tatra Mountains (alpine lakes) over the industrial period. Sulphur outputs from these ecosystems were comparable to inputs during a period of relatively stable atmospheric deposition (10-35 mmol m-2 yr-1) around the 1930s. Atmospheric inputs o...

2006
Charles C. Rhoades

American chestnut trees once dominated vast areas of deciduous forest in eastern North America, but the exotic chestnut blight almost eliminated the species from the region. Introduction of blight-resistant American chestnut hybrids will probably start in the next decade after many years of tree breeding. What were the historic effects of chestnut on forest soils, and what changes may follow re...

2002
Klaus Butterbach-Bahl Florian Stange Hans Papen Changsheng Li

Though it has been shown recently that forest ecosystems affected by high rates of atmospheric N input are significant sources of N trace gases, reliable regional estimates of the source strength of such forests are missing. In this study, the biogeochemical model Photosynthesis and Evapotranspiration-Nitrification-Denitrification and Decomposition (PnET-N-DNDC), which simulates processes invol...

Journal: :FEMS microbiology ecology 2013
Acácio A Navarrete Eiko E Kuramae Mattias de Hollander Agata S Pijl Johannes A van Veen Siu M Tsai

This study focused on the impact of land-use changes and agricultural management of soybean in Amazon forest soils on the abundance and composition of the acidobacterial community. Quantitative real-time PCR (q-PCR) assays and pyrosequencing of 16S rRNA gene were applied to study the acidobacterial community in bulk soil samples from soybean croplands and adjacent native forests, and mesocosm s...

1997
Vladimir Stolbovoi

By manifesting the response of land to human activity and impacts, degradation of forestland indicates the locations where society is in conflict with sustaining the forest environment. The analysis of land degradation in various land-use/cover patterns of Russia’s vast forest zone (about 1050 million ha, or 63% of the country) clearly demonstrates two human-induced problems, inappropriate tech...

ژورنال: علوم آب و خاک 2010
حاج عباسی, محمد علی, فلاح زاده , جابر ,

Determination of carbohydrates in soil requires prior extraction and numerous extraction methods were suggested for this purpose. Three methods and five extractants were applied in order to extract carbohydrate fraction in three soil types forest, clayey and saline soils. The extraction methods were: 1) shaken in a plane rotary shaking machine for 16 h 2) heated in steam-bath for 2.5 h and 3) h...

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