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1.
Tania Khandakar Chris Guppy Sheikh M. F. Rabbi Heiko Daniel 《Soil Use and Management》2021,37(1):120-125
Soil carbon (C) saturation implies an upper limit to a soil's capacity to store C depending on the contents of silt + clay and poorly crystalline Fe and Al oxides. We hypothesized that the poorly crystalline Fe and Al oxides in silt + clay fraction increased the C saturation and thus reduced the capacity of the soil to sorb additional C input. To test the hypothesis, we studied the sorption of dissolved organic carbon (DOC) on silt + clay fractions (<53 µm) of highly weathered oxic soils, collected from three different land uses (i.e., improved pasture, cropping and forest). Soils with high carbon saturation desorbed 38% more C than soils with low C saturation upon addition of DOC, whereas adsorption of DOC was only observed at higher concentration (>15 g kg?1). While high Al oxide concentration significantly increased both the saturation and desorption of DOC, the high Fe oxide concentration significantly increased the desorption of DOC, supporting the proposition that both oxides have influence on the DOC sorption in soil. Our findings provide a new insight into the chemical control of stabilization and destabilization of DOC in soil. 相似文献
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Freshwater fishes are threatened globally, and often too little is known about threatened species to effectively guide their conservation. Habitat complexity is linked to fish species diversity and persistence, and degraded streams often lack habitat complexity. Beaver Castor spp., in turn, have been used to restore streams and increase habitat complexity. The northern leatherside chub Lepidomeda copei is a rare, small‐bodied, drift‐feeding minnow that has anecdotally been observed to use complex habitats associated with beaver dams in the western United States. To investigate this anecdote, we conducted fish and habitat surveys, the latter focusing on quantifying habitat complexity, in a sub‐basin of the Upper Snake River Basin in the USA. Complementary generalised linear model and path analyses revealed that northern leatherside chub occurred more often at sites with complex streamflows, and streamflows were more complex when beaver dams were present and pools were deeper. Northern leatherside chubs were also more likely to occur when temperatures were warmer, aquatic macrophytes were abundant and stream channels were narrow and deep. The linkage between chubs, complex streamflows and beaver dams needs to be evaluated more broadly to completely understand its role in the rangewide status of the species. However, it does suggests that increased use of beaver reintroductions and dam analogues for stream restoration could be a boon for the northern leatherside chub, but such efforts should be monitored to determine their effectiveness to help adapt beaver‐based restoration approaches to best benefit the species. 相似文献
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Aamir Lal Eui-Joon Kil Vo T. B. Thuy Chairina Fadhila Phuong T. Ho Hee-Seong Byun Hang T. Dao Ji-Kwang Kim Sukchan Lee 《Plant pathology》2020,69(6):1026-1033
Milk vetch dwarf virus (MDV) is an important member of the genus Nanovirus and is transmitted by the aphid Aphis craccivora. MDV has multiple single-stranded DNA genome components, each approximately 1 kb, and two or three alpha-satellite molecules. It mainly infects plants of the legume family Fabaceae. Recently, papaya (Carica papaya) collected in Yesan, South Korea, displaying symptoms of leaf yellowing and dwarfism, was identified as a new host for MDV. To examine the geographical distribution of MDV, papaya samples with symptoms were harvested in South Korea, Vietnam, and Taiwan in August 2018, along with tomato and pepper samples grown in adjacent fields in Vietnam. The results revealed the presence of MDV not only in papaya but also in pepper and tomato. This MDV infection in members of the Solanaceae family was confirmed by Southern blot hybridization performed using a PCR product of segment S as a probe. Based on sequence analysis of three MDV components (M, S, and C3), we verified the presence of three different isolates of MDV in these three countries and homology between sequences of isolates from papaya and from members of the Solanaceae from Vietnam. Taken together, our results clearly demonstrate MDV infection in Vietnam and Taiwan for the first time and confirm that MDV can infect economically important pepper and tomato. 相似文献
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Mark D. Rawling Nicola Pontefract Ana Rodiles Ilektra Anagnostara Eric Leclercq Marion Schiavone Mathieu Castex Daniel L. Merrifield 《Journal of the World Aquaculture Society》2019,50(6):1108-1122
Fish were fed a single‐strain yeast fraction (SsYF; 2 g/kg) or a multistrain yeast fraction (MsYF; 0.8 g/kg) for 10 weeks. The results demonstrated significant (p ≤ 0.03) elevations in weight gain, specific growth rate, protein efficiency ratio, and feed conversion ratio in fish fed the yeast fraction‐supplemented diets. In the distal intestine, a significant elevation in microvilli density was observed after 5 and 10 weeks of dietary supplementation with MsYF and SsYF, respectively, compared to control fed fish (p < 0.001). A significant elevation (p = 0.02) in the perimeter ratio was observed in fish fed diets supplemented with the yeast fractions. After 10 weeks of feeding on the experimental diets, Rt‐qPCR demonstrated a significant downregulation (p < 0.05) in the stress response genes, heat‐shock protein 70 (hsp70) and proliferating cell nuclear antigen (pcna), in fish fed diets supplemented with the yeast fractions. Significant (p < 0.05) elevations in interleukin 1‐beta (il1β) and interleukin‐10 (il10) gene expression were observed in fish fed diets supplemented with the MsYF compared to the other dietary groups. These findings suggest that feeding an MsYF specifically at a lower incorporation rate < 1 g/kg, compared to a commercial SsYF at 2 g/kg, is effective in improving the intestinal health status and growth performance of European seabass. 相似文献
6.
Silage and total mixed ration hygienic quality on commercial farms: implications for animal production 下载免费PDF全文
T. Cogan R. Hawkey E. Higgie M. R. F. Lee E. Mee D. Parfitt J. Raj S. Roderick N. Walker P. Ward J. M. Wilkinson 《Grass and Forage Science》2017,72(4):601-613
Implications of silage hygienic quality for animal production were investigated on forty‐five dairy farms in South West England. Samples of grass and maize silages and of total mixed rations (TMR) were obtained together with information on silage technology, herd size and animal production. Samples were analysed for mycotoxins, bacteria, yeasts, moulds and chemical composition. Thirteen mycotoxins were assayed, but none were detected in the samples of grass silage. However, mycotoxins were found in 0·9 of all maize and other silage samples, with deoxynivalenol and zearalenone predominating. There was no relationship between total mycotoxin concentration and mean lactation milk yield per cow. Enterobacteria counts tended to be higher in maize silage than in grass silage and higher still in TMR – a cause for concern. There were no relationships between mould counts and mycotoxin concentrations in silages, implying that mycotoxins may have been produced in the field pre‐ensiling. 相似文献
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Spyra Marcin Kleemann Janina Cetin Nuket Ipek Vázquez Navarrete Cesar Jesús Albert Christian Palacios-Agundez Igone Ametzaga-Arregi Ibone La Rosa Daniele Rozas-Vásquez Daniel Adem Esmail Blal Picchi Paolo Geneletti Davide König Hannes J. Koo HongMi Kopperoinen Leena Fürst Christine 《Landscape Ecology》2019,34(7):1715-1735
Landscape Ecology - Several case studies investigated the role of ecosystem services in participatory planning processes. However, no systematic study exists that cuts across a large number of... 相似文献
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