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| Registros recuperados: 238 | |
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| Bjorneberg, D.L.; Leytem, A.B.; Ippolito, J.A.; Koehn, A.C.. |
| Watersheds utilizing surface water for irrigation often return a portion of the water to a water body. This irrigation return flow often includes sediment and nutrients that reduce the quality of the receiving water body. Research in the 82,000 ha Upper Snake Rock (USR) watershed from 2005 to 2008 showed that, on average, water diverted from the Snake River annually supplied 547 kg/ha of total suspended sediment (TSS), 1.1 kg/ha of total phosphorus (TP) and 0.50 kg/ha of dissolved phosphorus (DP) to the irrigation tract. Irrigation return flow from the USR watershed contributed 414 kg/ha of TSS, 0.71 kg/ha of TP and 0.32 kg/ha of DP back to the Snake River. Significantly more TP flowed into the watershed than returned to the Snake River while there was no... |
| Tipo: Article |
Palavras-chave: Irrigation control; Nutrients. |
| Ano: 2015 |
URL: http://eprints.nwisrl.ars.usda.gov/1586/1/1543.pdf |
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| Lentz, R.D.; Westermann, D.T.; Lehrsch, G.A.. |
| Few studies have comprehensively examined nutrient losses in runoff from furrow-irrigated fields, but the rising cost of fertilizer and finite nature of the resource encourages further research. A 2-yr experiment measured runoff losses of sediment, particulate P and N, and dissolved NO3-N, NH4-N, K, and reactive P (DRP) from fertilized, manured, or non-amended fields. Average nutrient losses were substantial, including 15.6 lbs ac/yr dissolved N, P, and K and 73.6 lbs ac/yr particulate N and P. The cost or replacing these nutrients with inorganic fertilizers was not trivial, at $54.69 ac/yr. Relative to non-amended soil, manure increased dissolved K, NO3-N, and DRP in runoff by 2.1x, 1.5x, and 2.7x, respectively. Other experiments evaluated the... |
| Tipo: Conference or Workshop Item |
Palavras-chave: Furrow irrigation; Runoff losses; Nutrients; Sediment. |
| Ano: 2013 |
URL: http://eprints.nwisrl.ars.usda.gov/1518/1/1482.pdf |
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| Aissaoui, A.; Turki, S.; Ben Hassine, O. K.. |
| Afin de fournir une meilleure idée sur la structure et la dynamique de la communauté des dinoflagellés et leurs relations avec les paramètres environnementaux dans les zones semi-fermées en communication avec le golfe de Tunis, une étude a été réalisée dans les ports puniques de Carthage afin d’estimer les densités et la dynamique des espèces de dinoflagellés ainsi que les variations des concentrations en nutriments, de janvier à juin 2006. Un nombre de 66 espèces de dinoflagellés ont été identifiés dont 14 espèces sont connues pour être nocives et responsables d’efflorescences nuisibles alors que 21 espèces sont connues pour être productrices de toxines. L'analyse statistique nous a permis de révéler des corrélations significatives entre les densités de... |
| Tipo: Journal Contribution |
Palavras-chave: Parameters; Nutrients (mineral); Coastal environment; Plankton; Nutrients; Plankton. |
| Ano: 2012 |
URL: http://hdl.handle.net/1834/5318 |
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| Soto, Doris; De los Ríos, Patricio. |
| La Patagonia de Chile posee muchos ecosistemas acuáticos sin contaminación, dentro de estos ecosistemas hay muchos lagos y lagunas prístinos. En este estudio, se analizó información colectada entre los años 1989 y 1990 (sin publicar y sin publicar) sobre lagos y lagunas del Parque Nacional Torres del Paine, un área sin contaminar en el sur de Chile (51° S). Se aplicó un análisis de componentes principales considerando parámetros químicos, riqueza de especies zooplanctónicas y biomasa. Los resultados denotaron que las concentraciones de cationes (Ca, Na y Mg), cloruros, seston y clorofila, junto con biomasa de zooplancton y riqueza de especies zooplanctónicas fueron las principales variables que contribuyeron al modelo obtenido. Según este modelo, se... |
| Tipo: Journal Contribution |
Palavras-chave: Lakes; Ponds; Chlorophylls; Zooplankton; Nutrients; Http://aims.fao.org/aos/agrovoc/c_5274. |
| Ano: 2009 |
URL: http://hdl.handle.net/1834/4167 |
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| Kyewalyanga, M.S.; Mwandya, A.W.. |
| Experiments to assess a suitable rate of fertilisation of earthen ponds for production of rotifers and protozoa were conducted in April 2000. Production of rotifers and protozoa (hereinafter collectively referred to as rotifers) was stimulated by flooding the ponds using seawater and rainfall. In the simulations, seawater diluted to 20 ppt salinity activated initial production. In all systems, the fertiliser concentration was approximately 1 ml of chicken manure to 2 litres of seawater. Three different rates of fertilisation were tested. The results clearly showed that the higher the frequency of addition of manure, the higher the production of rotifers per ml. Fertilised ponds had maximum averages of between 64 and 76 rotifers/ml as compared to a maximum... |
| Tipo: Journal Contribution |
Palavras-chave: Rotifers; Fertilisation rate; Earthen ponds; Nutrients; Simulatioru. |
| Ano: 2002 |
URL: http://hdl.handle.net/1834/22 |
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| Lyimo, T.J.; Hamisi, M.I.; Muruke, M.H.S.. |
| We report on the occurrence and diversity of cyanobacteria in intertidal seagrass meadows at Ocean Road and Mjimwema, Dar es Salaam, Tanzania. Nutrients, temperature and salinity were measured as comparative environmental factors. A total of 19 different cyanobacteria taxa were encountered, out of which eight were found exclusively in Mjimwema, four exclusively in Ocean Road and seven were common to both sites. Oscillatoria, Lyngbya and Spirulina were the dominant cyanobacterial genera. Cyanobacterial coverage was higher in Mjimwema (31–100%) than in Ocean Road (0–60%). The levels of nutrients in tidal pool waters at Ocean Road ranged from 0.45–1.03 ìmol NO3 -N/l, 0.19–0.27 ìmol NO2 -N/l and 0.03–0.09 ìmol PO4 -P/l. At Mjimwema the nutrient concentration... |
| Tipo: Journal Contribution |
Palavras-chave: Sea grass; Salinity; Temperature; Bacteria; Nutrients; Salinity; Temperature; Http://aims.fao.org/aos/agrovoc/c_5274; Http://aims.fao.org/aos/agrovoc/c_6751; Http://aims.fao.org/aos/agrovoc/c_7657. |
| Ano: 2004 |
URL: http://hdl.handle.net/1834/1137 |
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| Mohammed, S.M.; Björk, M.; Björklund, M.; Semesi, A.. |
| The release of inorganic nutrients into the sea by domestic sewage is a major threat to many marine systems. This eutrophication affects coral-reef organisms indirectly by increased growth of microalgae, leading to increased sedimentation, decreased light availibility, rapid growth of opportunistic macroalgae, etc. In this paper, we report a decrease in the cover of important group of coral-reef builders, the coralline algae. This decrease might be caused by the outlets of sewage water from Zanzibar town. Laboratory and field experiments show that both the growth rate and the calcification of these organisms are negatively affected by high phosphate levels, but not by nitrate or ammonia. |
| Tipo: Journal Contribution |
Palavras-chave: Sewage; Algae; Eutrophication; Coral reefs; Nutrients; Environmental degradation; Http://aims.fao.org/aos/agrovoc/c_5274; Http://aims.fao.org/aos/agrovoc/c_34821. |
| Ano: 1995 |
URL: http://hdl.handle.net/1834/302 |
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| The IODE workshop on quality control (QC) of chemical oceanographic data collections was held at the IOC Project Office for IODE in Oostende, Belgium between 8 and 11 February 2010. The meeting, proposed and organized by the IODE Group of Experts on Biological and Chemical Data Management and Exchange Practices (GE-BICH), welcomed 19 experts in chemical data management as well as data producers and users from 13 countries. The objective of the workshop was to evaluate existing procedures and define a minimum set of QC tests and criteria for dissolved inorganic nutrients (phosphate, silicate, nitrate+nitrite, nitrate, nitrite, and ammonium) and dissolved oxygen in seawater. The meeting produced several outcomes. First, the meeting identified two proposals... |
| Tipo: Report |
Palavras-chave: Oceanographic data; Workshops; Nutrients; Http://aims.fao.org/aos/agrovoc/c_26838; Http://aims.fao.org/aos/agrovoc/c_5274. |
| Ano: 2010 |
URL: http://hdl.handle.net/1834/4312 |
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| Andrade, Guilherme de Castro; Bellote, Antonio Francisco Jurado; Ferreira, Carlos Alberto; Silva, Helton Damin da. |
| Acacia mearnsii is the third forest species more planted in Brazil, especially in small farms at Rio Grande do Sul State. The species is also known as black wattle and is important as a source of tannin, timber, pulpwood and rayon. Its fast growth results in high demand of nutrients and fertilization is necessary to keep site productivity. In this paper it is reported the results of the application of four doses of Phosphorous (0, 20, 40, 80g/tree as P2O5) and three of Potassium (0, 20, 40g/tree as K2O), in a factorial designed trial established on a chemically poor soil at the region of Ponta Grossa, State of Paraná, Brazil. Trees were implanted in a 3m X 2m spacing with 35 plants per plot. The fertilizers were applied in furrows between the rows at the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Reforestation; Fertilization; Nutrients; Phosphorous; Potassium; Wood productivity Reflorestamento; Fertilização; Nutrientes; Fósforo; Potássio; Produtividade de madeira. |
| Ano: 2004 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/1596 |
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| Andrade, Guilherme de Castro; Silva, Helton Damin da; Bellote, Antonio Francisco Jurado; Ferreira, Carlos Alberto. |
| No Brasil, os plantios de árvores de rápido crescimento, principalmente espécies de Eucalyptus e de Pinus, representam uma oferta de milhares de empregos e significativa contribuição ao PIB. Do ponto de vista ambiental, contribuem para reduzir a pressão sobre as florestas nativas, concorrendo assim para a sua preservação e a dos recursos naturais nelas existentes. Esses povoamentos florestais, implantados na sua maioria em solos de baixa fertilidade, apresentam altas taxas de crescimento, necessitando de quantidades significativas de água e nutrientes do solo, o que causa preocupações com a sustentabilidade desses sistemas e com a necessidade de reposição futura de nutrientes. A utilização de resíduos para esta finalidade é considerada prioritária. Neste... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Reflorestamento; Fertilização; Nutrientes; Fósforo; Produtividade de madeira Reforestation; Fertilization; Wastes; Nutrients; Phosphorous; Wood productivity. |
| Ano: 2003 |
URL: http://pfb.cnpf.embrapa.br/pfb/index.php/pfb/article/view/1607 |
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| Carvalho,L.B; Alves,P.L.C.A; Bianco,S. |
| The objective of this work was to evaluate the coexistence effects of coffee (Coffea arabica) with densities of sourgrass (Digitaria insularis) on crop macronutrient content and plant growth. The experiment was conducted in plots where one coffee plant was maintained in coexistence with 0 (weed-free check), 1, 2, 4, 8, and 16 sourgrass plants, using a completely randomized design with three replicates. Reduction of coffee growth and macronutrient content, except P that increased, started when the coexistence occurred with sourgrass plants in a density of 1 plant per plot. In general, macronutrient content was reduced by 18-50%, while growth characteristics were reduced by 9-41%, when coffee plants coexisted with 16 plants of sourgrass. Thus, sourgrass... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Coffea arabica; Digitaria insularis; Competition; Additive experiment; Nutrients. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582013000100012 |
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| Ali,H.H.; Tanveer,A.; Naeem,M.; Jamil,M.; Iqbal,M.; Chadhar,A.R.; Kashif,M.S.. |
| Rhynchosia capitata is a newly emerging threatening weed of summer crops in many Asian countries. We conducted 2-yr experiments to evaluate R. capitata competition with mungbean under irrigated conditions. Rhynchosia capitata was allowed to compete with mungbean for 0, 3, 4, 5, 6, 7 weeks after planting and for full crop season. The competitive ability of R. capitata was assessed by measuring its dry weight, micro and macro nutrient contents and uptake; and its effects on mungbean growth and yield parameters. The results showed that full season weed competition produced highest dry weight of R. capitata and its macro and micronutrient contents and uptake. Yield and yield components of mungbean decreased in a linear fashion with increase in competition... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Rhynchosia capitata; Emerging; Infestation; Competition; Mungbean; Nutrients. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-83582015000200175 |
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| Registros recuperados: 238 | |
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