Tape depth and germination method influence patterns of salt accumulation with subsurface drip irrigation   总被引：3，自引：0，他引：3  

Trenton L. Roberts  Scott A. White  Arthur W. Warrick  Thomas L. Thompson   《Agricultural Water Management》2008,95(6):669-677

Subsurface drip irrigation (SDI) can result in accumulation of soluble salts at or near the soil surface. In the southwestern USA, rainfall is usually inadequate for stand establishment, thus supplemental irrigation is necessary. Use of sprinklers to minimize salt concentrations near the soil surface is an alternative to using SDI for stand establishment. Our objective was to evaluate the effects of germination method (irrigation with SDI or sprinklers), depth of SDI tape (0.18 and 0.25 m), and irrigation water salinity (1.5 and 2.6 dS m⁻¹) on salt and Br distribution after each of two consecutive growing seasons. Treatments consisted of factorial combinations of these three factors. Bromide was used to trace salt accumulation from the drip tape. After season 1, the highest salt concentrations (ECe up to 11 dS m⁻¹) were in the top 3 cm of soil. Below 3 cm, soil EC dropped significantly and remained constant to 1.05 m. Similarly, Br concentrations were highest in the top 3 cm of soil. The mass of salt and Br recovered in the top 3 cm were significantly affected by tape depth, and water EC significantly affected salt mass. Salt present in the soil after season 1 adversely affected crop emergence in season 2, where SDI was used for stand establishment. After season 2, the highest salt and Br concentrations were at about 25 cm depth, probably due to 210 mm of rainfall that occurred near the end of the growing season. There were no significant differences among treatments in the mass of either salt or Br in the top 3 cm or 16 cm of the soil profile after season 2. Timely rainfall, transplanting rather than direct seeding, and changing bed geometry can reduce dependence on sprinklers for stand establishment.  相似文献   

Survival and growth of upland oak and co-occurring competitor seedlings following single and repeated prescribed fires     

Heather D. Alexander  Mary A. Arthur  David L. Loftis  Stephanie R. Green 《Forest Ecology and Management》2008

Studies within and outside the U.S. indicate recurring oak (Quercus spp.) regeneration problems. In deciduous forests of the eastern U.S., a prevailing explanation for this trend is fire suppression leading to high competitor abundance and low understory light. In response, prescribed fire is increasingly used as a management tool to remedy these conditions and encourage future oak establishment and growth. Within eastern Kentucky, we implemented single and repeated (3×) prescribed fires over a 6-yr period (2002–2007). Pre- and post-burn, we quantified canopy cover and oak seedling survival and growth compared to other woody seedlings deemed potential competitors, primarily red maple (Acer rubrum L.) and sassafras (Sassafras albidum (Nutt.) Nees.). Burning temporarily decreased canopy cover 3–10%, but cover rebounded the subsequent growing season. Repeated burning ultimately produced canopy cover about 6% lower than sites unburned and burned once, suggesting a cumulative effect on understory light. Red maple exhibited low survival (∼40%) following single and repeated burns, but growth remained similar to unburned seedlings. Burning had little impact on sassafras survival and led to total height and basal diameters 2× greater than unburned seedlings. A single burn had no impact on red oak (Erythrobalanus spp.) survival and increased height and basal diameters 25–30%, but this positive growth response was driven by seedlings on several plots which experienced high burn temperatures and consequently high overstory mortality. White oaks (Leucobalanus spp.), however, exhibited twice as high mortality compared to those unburned, with no change in growth parameters. Repeated burning negatively impacted survival and growth of both oak groups compared to unburned seedlings. With both burn regimes, oaks with smaller pre-burn basal diameters exhibited the lowest post-burn survival. Thus, despite the ability of prescribed burns to temporarily increase understory light and reduce red maple survival, neither single or repeated burns placed oaks in an improved competitive position. These findings result from a combination of highly variable yet interdependent factors including the (1) life history traits of oaks compared to their co-occurring competitors, (2) pre-burn stature of pre-existing oak seedlings, and (3) variability in fire temperature and effects on understory light.  相似文献   

Hematology of dugongs (Dugong dugon) in southern Queensland          下载免费PDF全文

Lucy Woolford  Arthur Wong  Helen L. Sneath  Trevor Long  Susan P. Boyd  Janet M. Lanyon 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2015,44(4):530-541

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Development of an arterial thrombosis model in pigs for investigating the thrombogenicity of different dietary fats     

D.G. Arthur  K.G. Thompson  K.A.C. James  A.J. Maccoll 《New Zealand veterinary journal》2013,61(1)

A surgically induced model of arterial thrombosis in pigs (60–80 kg live weight) has been developed using a balloon angioplasty technique. The purpose of this model is to assess the thrombogenicity of milkfat in comparison with other dietary lipids, thereby assessing its importance in the pathogenesis of human coronary heart disease. Balloon angioplasty catheters (Meditech, 3 cm X 8 mm balloon) are inserted into the left and right femoral arteries via a cut-down on to the saphenous artery. The balloons are inflated five times for 30 seconds with 30 second intervals between inflations. This results in endothelial denudation, exposure of sub-endothelial connective tissue and formation of platelet rich thrombi. Thrombus size is quantitated using autologous blood platelets labelled with ⁹⁹Tc-HMPA0 (technetium - “Deretec”).  相似文献   

Efficacy of furosemide in the treatment of exercise-induced pulmonary hemorrhage in Thoroughbred racehorses     

J R Pascoe  A E McCabe  C E Franti  R M Arthur 《American journal of veterinary research》1985,46(9):2000-2003

The repeatability of endoscopic observations of exercise-induced pulmonary hemorrhage (EIPH) and the efficacy of furosemide as a prophylactic treatment of horses with EIPH were studied in Thoroughbred race horses after consecutive breezes (at or near maximum speed, approx 16 m/s). Of 56 horses examined greater than or equal to 2 times, 21 (38%) had identical EIPH scores, whereas 26 (46%) and 9 (16%) had scores that differed by greater than or equal to 1 grade. In 56 nontreated horses, there was good agreement between 2 consecutive observations (K = 0.59, Z = 4.54, P less than 0.001). Similar comparisons after placebo (saline solution) treatment of 21 horses yielded fair to good agreement, whereas poorer agreement was seen after furosemide treatment of 23 horses. Comparison of average and maximum EIPH scores of 44 horses with a minimum of 4 observations (2 nontreated, 1 saline-treated, and 1 furosemide-treated) indicated that although furosemide did not stop EIPH, it did reduce the EIPH score in 28 (64%) horses.  相似文献   

Reproduction and genital diseases of the camel     

G H Arthur  A T al-Rahim  A S al-Hindi 《The British veterinary journal》1985,141(6):650-659

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Canine ovariectomy by hybrid or total natural orifice transluminal endoscopic surgery: technical feasibility study and pain assessment     

Marcella Teixeira Linhares  Joo Pedro Scussel Feranti  Gabriela Pesamosca Coradini  Letícia Reginato Martins  Arthur Rodrigues Martins  Vanessa Zanchi Sarturi  Felipe Baldissarella Gavioli  Marco Augusto Machado Silva  Michelli Westphal de Ataíde  Luciana Gonalves Teixeira  Maurício Veloso Brun 《Veterinary surgery : VS》2019,48(Z1):O74-O82

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A comparison of morphology,pathogenicity and restriction fragment patterns of mitochondrial DNA among isolates of Phytophthora porri Foister     

Arthur W. A. M. De Cock  Afra Neuvel  Günther Bahnweg  Johanna C. J. M. De Cock  Hermann H. Prell 《European journal of plant pathology / European Foundation for Plant Pathology》1992,98(5):277-289

Thirteen strains ofPhytophthora porri from five different hosts were compared with respect to their morphology, cardinal temperatures for growth, pathogenicity to leek and cabbage and restriction fragment patterns of mitochondrial DNA. Morphology of vegetative growth was rather similar in most isolates. Those characters which differed among isolates showed overlapping variability and could not be used to distinguish groups, with the exception of production of oogonia and sporangia and the antheridium type. Considerable differences were found in restriction patterns of mitochondrial DNA, isolates from the same host mostly showing identical patterns. Isolates from differentAllium species showed relatively similar restriction patterns if compared to the other isolates. Isolates fromBrassica oleracea proved to be a homogeneous group, quite different from the others with respect to restriction patterns, production of sporangia, production of oogonia, antheridium type and pathogenicity. One isolate, CBS 366.59, isolated from and pathogenic toA. porrum, deviated in many characters from the other isolates. It showed the restriction patterns ofPhytophthora nicotianae and also the high cardinal temperatures for growth typical for this species. The sporangia, however, were distinctly non-papillate and the majority of antheridia was of the paragynous type.  相似文献   

Hereditary chondrodysplasia ("spider syndrome") in a New Zealand Suffolk lamb of American origin     

West DM  Burbidge HM  Vermunt JJ  Arthur DG 《New Zealand veterinary journal》1995,43(3):118-122

The first case of hereditary chondrodysplasia ("spider syndrome") in a New Zealand Suffolk lamb of American origin is described. An imported Suffolk ram of American origin was test mated to 27 of his daughters. In one of the resulting progeny, found dead at birth, a diagnosis of hereditary chondrodysplasia was made based on the typical radiographical abnormalities of multiple centres of ossification in the anconeal process of the ulna, vertebrae, sternebrae and pelvic bones. These changes were confirmed histopathologically.  相似文献   

Habitat functional response mitigates reduced foraging opportunity: implications for animal fitness and space use     

Garrett M. Street  John Fieberg  Arthur R. Rodgers  Michelle Carstensen  Ron Moen  Seth A. Moore  Steve K. Windels  James D. Forester 《Landscape Ecology》2016,31(9):1939-1953

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