نتایج جستجو برای: topsoil

تعداد نتایج: 1920  

Journal: :Journal of medical entomology 2002
Champa N K Rajapakse Roger Meola Janice Readio

The efficacy of a photostable formulation of methoprene and two photostable juvenoids, fenoxycarb and pyriproxyfen, and their residual activity in inhibiting the emergence of adult cat fleas, Ctenocephalides felis (Bouché), was studied in topsoil. Nursery pots composed of clay, peat, and plastic, and wooden flats were used to hold soil samples. Treated soil samples were exposed to sunlight duri...

2017
I. P. Holman J. M. Hollis M. E. Bramley T. R. E. Thompson

During the autumn of 2000, England and Wales experienced the wettest conditions for over 270 years, causing significant flooding. The exceptional combination of a wet spring and autumn provided the potential for soil structural degradation. Soils prone to structural degradation under five common lowland cropping systems (autumn-sown crops, late-harvested crops, field vegetables, orchards and sh...

2014
Carla Candeias Eduardo Ferreira da Silva Paula F. Ávila João Paulo Teixeira Jose A. Centeno

The Sn-W Panasqueira mine, in activity since the mid-1890s, is one of the most important economic deposits in the world. Arsenopyrite is the main mineral present as well as rejected waste sulphide. The long history is testified by the presence of a huge amount of tailings, which release considerable quantities of heavy metal(loid)s into the environment. This work assesses soil contamination and...

2012
Tie-yu Wang Bing Tan Yong-long Lu

The concentrations of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in the topsoil samples around the Guanting Reservoir in Beijing were measured, and their spatial distribution and environmental risks were analyzed by GIS. The results showed that in 2003, 2007, and 2009, the HCHs concentrations were 0.66, 0.85, and 0.73 ng/g, and the DDTs concentrations were 9.50, 7...

Journal: :Pest management science 2012
Alegría Cabrera Sharon K Papiernik William C Koskinen Pamela J Rice

BACKGROUND Sorption and dissipation of aged metolachlor were characterized in rehabilitated and eroded prairie soils using sequential batch slurry (conventional) and accelerated solvent extraction (ASE). RESULTS In spite of an almost twofold difference in soil organic carbon (OC) content, S-metolachlor sorption coefficients (K(d)) and dissipation rates (DT(50)) were the same in soils from dif...

Journal: :Environmental science & technology 2005
Cong Hu Tian C Zhang Yong H Huang Mohamed F Dahab Rao Surampalli

The buildup of phosphorus (P) in the soil is a major factor limiting the operating life of a wastewater land treatment system. In this study, we evaluated changes of chemical properties, P profiles, and adsorption isotherms in the soils of a Muskegon wastewater land treatment system, which has received wastewater for approximately 30 years. It was found that the pH in the 15-cm topsoil increase...

2000
GRAHAM P. SPARLING

Marton (Argillic Perched-gley Pallic, Typic Endoaqualf), Ohakune (Typic Orthic Allophanic, Typic Hapludand), and Westmere (Mottled Mafic Melanic, Mollic Hapludalf) soils with differing structural vulnerability were compared at matched sites under different land uses. Topsoil samples (0-10 cm) from indigenous forest (>50 yr), permanent pasture (>50 yr), pine plantation (>20 yr), or arable croppi...

2012
Laura Quijano Leticia Gaspar Marcos A.E. Chaparro Ana Navas

The magnetic susceptibility (MS) in soils is a fast and non-destructive technique that can be used to infer the concentration of magnetic minerals. The objective of this study was to analyze MS on topsoil and bulk core samples of cultivated Calcisols. Magnetic susceptibility was measured at two different frequencies to assess the variation of magnetic susceptibility when the frequency of the ap...

2016
Li Lin Biao Zhu Chengrong Chen Zhenhua Zhang Qi-Bing Wang Jin-Sheng He

Soils in the alpine grassland store a large amount of nitrogen (N) due to slow decomposition. However, the decomposition could be affected by climate change, which has profound impacts on soil N cycling. We investigated the changes of soil total N and five labile N stocks in the topsoil, the subsoil and the entire soil profile in response to three years of experimental warming and altered preci...

2015
Marie Uksa Michael Schloter David Endesfelder Susanne Kublik Marion Engel Timo Kautz Ulrich Köpke Doreen Fischer

Microbial communities in soil provide a wide range of ecosystem services. On the small scale, nutrient rich hotspots in soil developed from the activities of animals or plants are important drivers for the composition of microbial communities and their functional patterns. However, in subsoil, the spatial heterogeneity of microbes with differing lifestyles has been rarely considered so far. In ...

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