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961.
962.
N. R. Atkinson S. D. Young A. M. Tye N. Breward E. H. Bailey 《Soil Use and Management》2012,28(4):559-570
Urban waste disposal occurred on fenland to the west of Manchester, England, between 1900 and 1964. The reclaimed fenland, Chat Moss, is now used for mixed arable farming. A total of 1.92 Mt of waste including privy midden, street sweepings, clinkers and slaughterhouse refuse was incorporated into the moss resulting in a modified topsoil with raised pH and reduced organic matter content compared with the subsoil. Elevated levels of potentially toxic elements (PTEs) are observed in the topsoil beyond the typical depth of atmospheric contamination; Cd and As concentrations exceed soil guideline values (SGVs) at 1.8 and 43 mg/kg, respectively. Sequential extraction indicates that waste‐derived Pb, Zn and Ni remain predominantly in the residual fraction, whereas Cu was mainly organically bound. Arsenic was predominately found in oxide and organic matter fractions with Cd in carbonate, oxide, organic matter and residual fractions. Pot trials indicated limited uptake of PTEs by vegetables grown on the waste‐amended soil, with the exception of Cd uptake by lettuce (0.22 mg/kg FW) and Pb uptake by radish (0.16 mg/kg FW), which exceeded current EU limits of 0.2 and 0.1 mg/kg FW, respectively. Hazard quotients (HQs) identified no risks to adults from consumption of vegetables grown in these soils with the exception of lettuce consumption with a HQ of 1.4. Risks to children were slightly greater with HQs >1 for Cd in lettuce, spinach, carrots and onion, As in lettuce, parsley and onion and for Zn in spinach. 相似文献
963.
D. Hagan C. Dobbs N. Timilsina F. Escobedo G. S. Toor M. Andreu 《Soil Use and Management》2012,28(1):78-88
We investigated the effects of various anthropogenic factors on urban soil properties in subtropical, coastal Tampa, FL, USA. Specifically, we explored the influence of (i) urbanization as measured by land use, land cover, population density and years since urban development and (ii) socioeconomic conditions as reflected in household income and property values on bulk density (BD) and several key soil chemical properties. Results indicate that Tampa’s urban soils were affected to varying degrees by these factors with chemical properties being more variable than BD. Across land uses significant differences were found for Mehlich‐1 (M1) extractable P, Ca and Na. A similar trend was observed for land‐cover classes, although significant differences were also found for pH and M1‐Cu. Soil properties had no statistically significant relationship with population density. However, time since urbanization did with M1‐P and Na varying significantly across age categories. For our socioeconomic analyses, M1‐K and Mg levels differed significantly by household income while pH, P, Ca and Na values differed significantly by property value. Overall, our findings indicate that despite their inherent heterogeneity, there are identifiable patterns among subtropical coastal urban soil properties. We suggest that a more thorough understanding of these patterns and their drivers is an essential first step towards developing soil management strategies aimed at maintaining environmental quality and ecosystem services in subtropical cities. 相似文献
964.
Performance of rainy season greengram as influenced by land configuration and phosphorus application
B. G. Shivakumar B. N. Mishra H. M. Thippeswamy S. S. Balloli 《Archives of Agronomy and Soil Science》2013,59(3-4):371-379
A field experiment was carried out for 2 crop years (July‐October) at the Indian Agricultural Research Institute, New Delhi to study the effect of land configuration and phosphorus levels on the growth and yield of rainy season greengram under limited irrigation facility. The crop sown on 2 meter wide broad bed and furrow (BBF) showed higher growth attributes, nodulation, yield attributes and yield compared to flat bed (FB) sowing. Application of 30 and 60 kg P2O5ha‐1 showed significant increase in growth attributes, nodulation, yield attributes and yield as compared to no phosphorus application. The moisture status in the soil determined the optimum dose of phosphorus needed for greengram. The combination of BBF sowing and application of 60 kg P2O5 ha?1 recorded the highest grain yield among all the combinations of land configuration and phosphorus levels. 相似文献
965.
966.
N. L. Biddington A. S. Dearman 《The Journal of Horticultural Science and Biotechnology》2013,88(4):609-614
SummaryMechanically-induced stress, applied by brushing young lettuce and cauliflower plants for 90 s each day, reduced the freezing resistance of cauliflower but had no effect on that of lettuce. Brushing reduced fresh weight in both species and smaller plants were less freezing-resistant than larger ones. The levels of abscisic acid (ABA) in the shoots of brushed cauliflowers were slightly less than in unbrushed plants, whereas in lettuce the levels were similar in the two treatments. ABA sprayed onto lettuce plants had no effect on freezing resistance. With both lettuce and cauliflower, freezing resistance, and the osmolarity of sap extracted from the shoots, increased following water-stress and declined progressively following rehydration. 相似文献
967.
N. M. Tainton 《African Journal of Range and Forage Science》2013,30(1):151-158
One of the ways in which grasses respond to varying conditions is by adjusting the growth rates of their different component parts relative to their overall growth rate. When plants are grown in constant conditions, increasing age brings about a decline in the growth rate of the leaf lamina component and an increase in the growth rate of the root component relative to the plant growth rate. Variations in temperature, photoperiod and in the daily amount of radiant energy received by the plant do, however, influence the distribution pattern of growth within the plant. 相似文献
968.
M.N. Bester 《African Zoology》2013,48(4):229-234
Population size of Arctocephalus tropicalis on Gough Island was determined by direct censuses of parts of the coast during the summers of 1974 – 1976 and 1977 – 1978 and correction factors for undercounting and seasonal cycles were applied. Present population size is approximately 200 000, giving an intrinsic rate of increase of 15,9% per year since 1955/56, but is now approaching the negative acceleration phase in population growth as a result of optimal breeding space becoming limited. An extension of breeding colony sites has also occurred since 1955. 相似文献
969.
970.
G.W. Smith J.L. Davis S.M. Smith M.P. Gerard N.B. Campbell D.M. Foster 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2010,24(4):949-955
Background: Despite frequent clinical use, information about the pharmacokinetics and efficacy of pantoprazole in camelids is not available. Objectives: To examine the pharmacokinetics of both IV and SC pantoprazole and to determine whether pantoprazole administration would increase 3rd compartment pH in alpacas. Animals: Six healthy adult alpacas. Methods: Alpacas were fitted with a 3rd compartment cannula for measuring gastric pH. After recovery, alpacas received 1 mg/kg pantoprazole IV, q24h for 3 days or 2 mg/kg SC q24h for 3 days. Alpacas received both IV and SC pantoprazole, with a minimum of 3 weeks between treatments. Third compartment pH was recorded and plasma samples were taken for pharmacokinetic analysis. Results: Pantoprazole induced a slow but sustained increase in 3rd compartment pH when given by both the IV and SC routes. Third compartment pH was significantly increased as compared with baseline values (1.81 ± 0.7; mean ± SD) at 24 (2.47 ± 0.8), 48 (3.53 ± 1.0) and 72 hours (4.03 ± 1.3) after daily IV administration of pantoprazole. Third compartment pH increased from 1.73 ± 0.6 at baseline to 3.05 ± 1.1, 4.02 ± 1.4, and 3.61 ± 1.6 at 24, 48, and 72 hours after SC administration, respectively. Pharmacokinetic analysis demonstrated that pantoprazole had a short elimination half‐life (0.47 + 0.06 h) and a high clearance rate (12.2 ± 2.9 mL/kg/min) after both IV and SC administration. Conclusions and Clinical Relevance: Based on the results of this study, pantoprazole represents a safe and effective drug for increasing 3rd compartment pH in camelids. Either IV or SC administration is likely to be an effective treatment for gastric ulcers. 相似文献