نتایج جستجو برای: upland
تعداد نتایج: 5084 فیلتر نتایج به سال:
We employed a Mohr-Coulomb safety factor equation to assess the response of ice-cemented slopes in the stable upland zone of the McMurdo Dry Valleys (MDV) to artificial increases in mean summertime soil surface temperatures (MSSST). Results show that ice-rich, silty tills on slopes 20° could fail by planar sliding with an increase in MSSST of ~5o to 9oC. This change corresponds to an atmospheri...
Agricultural and urban development causes nutrients to become concentrated at upland sites (Drexler and Bedford, 2002; Detenbeck et al., 2002). The subsequent flux of these nutrients through ground and surface water flow often overwhelms the receiving waters; the ability of lakes, rivers, and streams to normally assimilate and transport these nutrients is surpassed and results abnormally high p...
The transformation of inorganic iodine (I(-) and IO(3)(-)) incubated in soils with varying amounts of organic matter (Andosols from the surface layer of an upland field and forest, as well as Acrisols from surface and subsurface layers of an upland field) was investigated by using the iodine K-edge X-ray absorption near-edge structure (XANES). After 60d of reaction, both I(-) and IO(3)(-) were ...
Long fire rotation, high levels of precipitation, and acidic nature of the bedrock are factors contributing to the dominance of Sphagnum in many upland and peatland communities in southeastern Labrador. Vegetation development induced by local or regional environmental change frequently involves replacement of species assemblages of various bryophytes and lichens by species assemblages dominated...
One-hundred twenty-three gizzards from upland game birds (chukar, Alectoris chukar; and common pheasant, Phasianus colchicus) harvested by hunters in southern Ontario, Canada, were examined for lead pellet ingestion by manual examination of gizzard contents and by radiography. Lead pellets were found to be ingested by chukars (6/76; 8%) and the common pheasant (16/47; 34%). Further, 13% (17/129...
Soil conservation efforts in Indonesia since the Dutch colonial era have focused on introducing bench terraces—a costly soil conservation method for poor, upland farmers. Data from two villages in the Kerinci uplands of Sumatra illustrate that even with state underwriting of bench terrace construction, farmers across all economic strata still resist using this method. Why the state has not purs...
The genetic diversity of 175 rice accessions from Myanmar, including landraces and improved types from upland and lowland ecosystems in five different areas-Western (hilly), Northern (mountainous), North and South-eastern (plateau), and Southern (plain)-was evaluated on the basis of polymorphism data for 65 DNA markers and phenol reactions. On the basis of the DNA polymorphism data, high geneti...
The reniform nematode (Rotylenchulus reniformis) is an important parasite of upland cotton (Gossypium hirsutum). Parasitism involves the formation of syncytia to provide nutrition for the female. Events that occur at the feeding site may determine the degree of susceptibility of cotton plants to reniform nematode. The objective of this work was to describe histological modifications associated ...
Breakdown of woody debris in river and upland habitats as well as the interactions between wood and invertebrates have been well described. Studies of wood in wetlands are rare, and far less is known about breakdown and invertebrate use of wood in these transitional habitats. This study experimentally assessed breakdown and invertebrate colonization of wood in a floodplain wetland and directly ...
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