Twenty years of tillage research in subarctic Alaska: I. Impact on soil strength, aggregation, roughness, and residue cover     

Brenton Sharratt  Mingchu Zhang  Stephen Sparrow 《Soil & Tillage Research》2006,91(1-2):75-81

Soil properties and surface characteristics affecting wind erosion can be manipulated through tillage and crop residue management. Little information exists, however, that describes the impact of long term tillage and residue management on soil properties in the subarctic region of the United States. This study examines the impact of 20 years of tillage and residue management on a broad range of physical properties that govern wind erosion processes on a silt loam in interior Alaska. A strip plot experimental design was established in 1983 and included intensive tillage (autumn and spring disk), spring disk, autumn chisel plow, and no tillage with straw either retained on or removed from the soil surface. Soil and residue properties measured after sowing barley (Hordeum vulgare L.) in May 2004 included penetration resistance, soil water content, shear stress, bulk density, random roughness, aggregate size distribution, and residue cover and biomass. No tillage was characterized by larger aggregates, greater soil strength (penetration resistance and shear stress), wetter soil, and greater residue cover compared to all other tillage treatments. Despite crop failures the previous 2 years, crop residue management influenced residue biomass and cover, but not soil properties. Autumn chisel and spring disk appeared to be viable minimum tillage options to intensive tillage in controlling erosion. Autumn chisel and spring disk promoted greater roughness, aggregation, and residue cover as compared with intensive tillage. Although no tillage appeared to be the most effective management strategy for mitigating wind erosion, no tillage was not a sustainable practice due to lack of weed control. No tillage also resulted in the formation of an organic layer on the soil surface over the past 20 years, which has important ramifications for long term crop production in the subarctic where the mean annual temperature is <0 °C.  相似文献   

Clinically and temporally specific diagnostic thresholds for plasma ACTH in the horse     

Andy E. Durham  Brenton R. Clarke  Julie F. N. Potier  Robert Hammarstrand  George L. Malone 《Equine veterinary journal》2021,53(2):250-260

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Treatment of supraventricular tachycardia in a horse          下载免费PDF全文

Dorothy D. Whelchel DVM  MS  DACVIM  Brett S. Tennent‐Brown BVSc  MS  DACVIM  DACVECC  Amanda E. Coleman DVM  DACVIM  Gregg S. Rapoport DVM  DACVIM  Uriel Blas‐Machado DVM  PhD  DACVP  Herbert W. Maisenbacher VMD  DACVIM  Brenton C. Credille DVM  PhD  DACVIM  Steeve Giguère DVM  PhD  DACVIM 《Journal of Veterinary Emergency and Critical Care》2017,27(3):362-368

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The relative importance of soil properties and regional climate as drivers of productivity in southern Patagonia’s <Emphasis Type="Italic">Nothofagus antarctica</Emphasis> forests     

Héctor A. Bahamonde  Guillermo Martínez Pastur  María V. Lencinas  Rosina Soler  Yamina M. Rosas  Brenton Ladd  Sandra Duarte Guardia  Pablo L. Peri 《Annals of Forest Science》2018,75(2):45

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