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31.
There is lack of information available concerning the effect of humic substances (HS) applied via fertigation on plant growth in sandy soils. Therefore, a field experiment was carried out at El‐Saff district (20 km southwest of Cairo), Egypt, to investigate the role of HS fertigation on water retention of a sandy soil, yield and quality of broccoli (Broccoli oleracea L.) as well as on soil nutrient concentration retained after harvest. The experiment consisted of six fertigation treatments (50%, 75%, and 100% of the recommended NPK‐fertilizer rate for broccoli combined with and without HS application at 120 L ha–1) in a complete randomized block design with three replicates. Humic substances affected spatial water distribution and improved water retention in the root zone. Furthermore, application of HS increased total marketable yield and head diameter of broccoli as well as quality parameters (i.e., total soluble solids, protein, and vitamin C). Higher nutrient concentrations were found in the broccoli heads and concentrations of plant‐available nutrients in soil after harvesting were also higher, indicating an improvement in soil fertility. In conclusion, HS fertigation can be judged as an interesting option to improve soil water and nutrient status leading to better plant growth. 相似文献
32.
A. Rigueiro‐Rodríguez M. R. Mosquera‐Losada E. Fernndez‐Núez 《Land Degradation u0026amp; Development》2012,23(3):227-241
Afforestation of abandoned agricultural lands has been the main change in land use over the past decade in Europe. However, the impact of tree species and understorey management on production and plant diversity over the medium‐ and long‐term has not been thoroughly studied. This paper aims to evaluate the effects of an afforestation of Pinus radiata D. Don and Betula alba L. on soil pH, understorey production and plant diversity and life cycle type (annuals vs. perennials) managed with different soil fertilisation treatments over a period of 11 years. The results show an acidification of the soil 11 years after establishment, better vertical growth and diameter of pine compared with birch as usually happens in the region and important variation in the biomass production and composition of the understorey below both tree species. Understorey species remained similar during the first 5 years below both canopies. However, species richness (S) was drastically reduced under Pinus radiata D. Don plantation compared to Betula alba L. (Spine = 2 vs. Sbirch = 17) after 11 years of tree establishment at a very high density (2500 trees ha−1). Inorganic and organic fertilisation also caused a reduction in floristic diversity. Soil pH, pasture production and floristic understorey plant diversity are better preserved under autochthonous broadleaves, which increased the multiple uses of recently afforested lands in the short‐ and medium‐term. In the European context of high need for sawn wood, the use of autochthonous broadleaved tree species like Betula should be promoted due to their better sustainability. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
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Marta C. Soares Jo Cable Monica G. Lima‐Maximino Caio Maximino Raquel Xavier 《Fish and Fisheries》2019,20(4):640-652
Recent research has revealed surprisingly important connections between animals’ microbiome and social behaviour. Social interactions can affect the composition and function of the microbiome; conversely, the microbiome affects social communication by influencing the hosts’ central nervous system and peripheral chemical communication. These discoveries set the stage for novel research focusing on the evolution and physiology of animal social behaviour in relation to microbial transmission strategies. Here, we discuss the emerging roles of teleost fish models and their potential for advancing research fields, linked to sociality and microbial regulation. We argue that fish models, such as the zebrafish (Danio rerio, Cyprinidae), sticklebacks (?Gasterosteidae), guppies (Poeciliidae) and cleaner–client dyads (e.g., obligate cleaner fish from the Labridae and Gobiidae families and their visiting clientele), will provide valuable insights into the roles of microbiome in shaping social behaviour and vice versa, while also being of direct relevance to the food and ornamental fish trades. The diversity of fish behaviour warrants more interdisciplinary research, including microbiome studies, which should have a strong ecological (field‐derived) approach, together with laboratory‐based cognitive and neurobiological experimentation. The implications of such integrated approaches may be of translational relevance, opening new avenues for future investigation using fish models. 相似文献
36.
Litea Meo‐Sewabu 《Asia Pacific viewpoint》2014,55(3):345-354
The praxis of an Indigenous Fijian researcher who is both an insider/outsider offers some valuable lessons for ethnographic work. This paper introduces ‘cultural discernment’ as a concept used to ensure that the research process is culturally ethical within the research setting. An insider will always require a sense of cultural discernment, recognising that actions taken have implications that are critical and remain with the researcher for life. The paper contextualises the concept of cultural discernment in relation to Fijian epistemology. Although there are risks within any research project with regard to ethics processes and the conduct of research, this paper will illustrate how Western paradigms associated with ‘expert knowledge’ and the ‘lay knowledges’ of an Indigenous population group produce competing understandings about ethical practice. The paper draws on a doctoral research project exploring the cultural conceptualisation of health and well‐being, conducted in Fiji and New Zealand. The research process and steps carried out in this study ensured those actions were culturally appropriate and ethically sound from an Indigenous Fijian perspective. 相似文献
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The ecological engineering of rivers has been emphasized in recent years; however, scant attention has been focused on the ecological environments of paddy fields and irrigation canals. In this study, a paddy field in Yuanli Township, Miaoli County, Taiwan, was used as a test field. We improved the ecological corridor, ensuring the continuity of the irrigation canal and paddy field, thereby enabling a constant flow of water in the longitudinal section of the paddy field corridor to facilitate smooth upstream migration of fish. Fish could also migrate upstream in the lateral section of the paddy field. Subsequently, loach were used to assess the effect of an enhanced rock pile in a pool area of the simplified paddy fishway, and fish were allowed to migrate up and down the paddy field and irrigation canal. The results indicated that the difference in water levels (i.e. a bottleneck for creating an ecological corridor) was enhanced by the simplified paddy‐field fishway and enhanced rock pile. In addition, removing bottlenecks along the ecological corridor enabled fish and shrimp to migrate in the longitudinal and lateral directions. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
39.
Do T Stephens C Townsend K Wu X Chapman T Chin J McCormick B Bara M Trott DJ 《Australian veterinary journal》2005,83(5):293-299
OBJECTIVE: To identify virulence genes in enterotoxigenic E coli (ETEC) isolates associated with diarrhoea in neonatal, 1 to 3 week-old and weaned pigs in southeast Queensland. DESIGN: Multiplex PCR and serotyping were applied to E coli isolates obtained over a 5-year period (1998-2002) from cases diagnosed at Toowoomba Veterinary Laboratory. PROCEDURE: A total of 126 isolates from 25 different Queensland piggeries were tested for haemolytic activity on 5% sheep blood agar and by multiplex PCR for the presence of five commonly recognised fimbrial (F4, F5, F6, F41 and F18) and three enterotoxin genes (STa, STb, LT). A subset of 62 representative isolates were serotyped by slide agglutination. For comparative purposes, multiplex PCR was also performed on the DNA of 31 ETEC isolates from 9 serotypes originating from piggeries in southern New South Wales. RESULTS: A total of 113 (89.7%) of the isolates from Queensland possessed ETEC virulence genes, including 14 of 15 isolates from neonatal pigs (93.3%), 18 of 23 isolates from 1 to 3 week old pigs (78.3%) and 81 of 88 isolates from weaned pigs (92.1%). F4:STa:STb:LT (serotype O149) was the most prevalent pathotype in neonatal and 1-3 week old pigs and F4:STa:STb:LT (serotype O149) and F18:STa:STb:LT (serotype O141) were most prevalent in weaned pigs. In comparison, isolates obtained from neonatal pigs from New South Wales belonged to a more diverse range of pathotypes and serotypes. CONCLUSION: Multiplex PCR was a rapid and specific method for detecting the presence of ETEC virulence genes in porcine E coli isolates. For isolates obtained from cases of suspected colibacillosis in Queensland, growth of a heavy pure culture of haemolytic E coli was a sensitive prognostic indicator of the presence of ETEC virulence genes in the isolate. ETEC pathotypes and serotypes remained stable in Queensland piggeries over the five-year study period and appear to have changed little over the last three decades. 相似文献
40.
Diana S. Vargas‐Bermudez Fabricio S. Campos Laura Bonil Darío Mogollon Jairo Jaime 《Veterinary Medicine and Science》2019,5(2):182-188
Porcine circovirus 3 (PCV3) was recently discovered and is a new species of the genus circovirus. Clinically, it is associated with absence of symptoms or with different clinical syndromes. It has been reported in different countries of America, Europe and Asia. Last year, in Colombia, some farms have reported symptoms similar to those caused by PCV2. Samples were taken from two farms located in the centre of the country, and the presence of PCV3 was determined by PCR in two samples, one from a pool of sera and another from mesenteric lymph node. The strains were fully sequenced (GenBank accession numbers MH327784 and MH327785) and classified into subgroups a1 and a2. According to this classification and its analysis, strain a2 is located within the group called “Linker” that may be evolving towards group “b”. In addition to the above, the two Colombian strains were compared with 104 strains reported in the GenBank database. The phylogenetic tree obtained grouped according to the classification of subgroups a1, a2, b1 and b2. It was found that subgroups a1 and a2 were well grouped when comparing whole genomes, but the same was not observed with the strains of group “b”. In the latter, no subgroups were evidenced when comparing complete genomes. It is suggested that a new classification of PCV3 subgroups should be proposed, based on whole genome sequences. This is the first report of PCV3 in Colombia and its complete genome sequence. 相似文献