نتایج جستجو برای: montmorillonitic soils
تعداد نتایج: 48709 فیلتر نتایج به سال:
ABSTRACT- Paddy soils make up the largest anthropogenic wetlands on earth. Present study was performed to investigate and compare soil formation of paddy soils with long-term rice cultivation history with non-paddy soils and study the effect of waterlogging on soil pedogenesis. Soil samples were taken from paddy and non-paddy soils derived from the same calcareous parent materials. Some pedogen...
Colloid transport in subsurface has received considerable attention recently because mobile colloids can facilitate the transport of heavy metals in soils to contaminate groundwater. Many studies on colloid mobility in the subsurface consider soils as well-defined porous media. Though similar in many aspects, soils are different from well-defined porous media. The authors emphasize the impacts ...
Calcium-rich zeolites control naturally occurring chemical degradation in the black soils (Vertisols and their intergrades). With the help of modern tools such as remote sensing, geographic information system, soil database, geological information, topography and other related datasets, an attempt was made to update the distribution of zeolitic soils in India. To ascertain the presence of Ca-ri...
Desiccation cracking and its implications will be more of an issue due to the global warming trends. Soils tend to shrink when they lose moisture. In particular, fine-grained soils are susceptible to shrinkage and the resulting volume change. Shrinkage can cause cracking of soils that can adversely impact the engineering properties and behavior of the soils. As a result, the integrity of struct...
Availability of Ectomycorrhizal Fungi to Black Spruce above the Present Treeline in Eastern Labrador
Ectomycorrhizal fungi (ECMF) are an important biotic factor in the survival of conifer seedlings under stressful conditions and therefore have the potential to facilitate conifer establishment into alpine and tundra habitats. In order to assess patterns of ectomycorrhizal availability and community structure above treeline, we conducted soil bioassays in which Picea mariana (black spruce) seedl...
To determine the abundance and distribution of bacterial and archaeal ammonia oxidizers in alpine and permafrost soils, 12 soils at altitudes of 4000-6550 m above sea level (m a.s.l.) were collected from the northern slope of the Mount Everest (Tibetan Plateau), where the permanent snow line is at 5800-6000 m a.s.l. Communities were characterized by real-time PCR and clone sequencing by targeti...
In the Ross Sea region of Antarctica, ornithogenic soils form on land under Adélie Penguin rookeries. Compared with mineral soils of the Ross Sea region, ornithogenic soils are generally high in microbial biomass, organic carbon, and total nitrogen and phosphorus, with high electrical conductivity and large variations in pH. The objective of this study was to assess the bacterial composition of...
Because of long-term chemical processes, metal bioavailability in field soils decreases with time. Metal toxicity may, therefore, be overestimated if toxicity data with freshly spiked soils are used to derive soil quality criteria, a current practice. In the present study, effects of the long-term processes, called aging, on copper partitioning and ecotoxicity are investigated. Twenty-five fiel...
Anaerobic soil conditions resulting from flooding often enhance release of phosphorus (P) to overlying water. Enhanced P release is well documented for flooded acidic soils; however, there is little information for flooded alkaline soils. We examined the effect of flooding and anaerobic conditions on P mobilization using 12 alkaline soils from Manitoba that were either unamended or amended with...
Permafrost and organic layer interactions over a climate gradient in a discontinuous permafrost zone
Permafrost is tightly coupled to the organic soil layer, an interaction that mediates permafrost degradation in response to regional warming. We analyzed changes in permafrost occurrence and organic layer thickness (OLT) using more than 3000 soil pedons across a mean annual temperature (MAT) gradient. Cause and effect relationships between permafrost probability (PF), OLT, and other topographic...
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