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Jaguariúna, Brazil

De S. Dos Santos M.,Sao Paulo State University | Ghini R.,Embrapa Environment | Fernandes B.V.,V and M Florestal LTDA | Silva C.A.,Federal University of Lavras
Australasian Plant Pathology | Year: 2013

The increased atmospheric carbon dioxide concentrations expected in the coming decades will result in changes in host-pathogen interactions. The present study aimed to evaluate the effect of high concentrations of CO2 in the air on the development of Ceratocystis wilt in two Eucalyptus clones (a hybrid of Eucalyptus urophylla and a cross between E. urophylla x E. camaldulensis). The clonal plantlets were cultivated under CO2 concentrations of 394 ± 10 μmol/mol (environmental condition), 553 ± 15 μmol/mol and 878 ± 70 μmol/mol in a controlled environment for 70 days and inoculated with Ceratocystis fimbriata conidia. In the treatments with 553 and 878 μmol/mol, the plants of both clones had greater growth (215 % and 219 % increases in leaf area and 22 % and 24 % in stem diameter, respectively), a longer incubation period (65 % for both CO 2 concentrations) and less disease severity (48 % and 78 % reduction, respectively) on average compared with the plants cultivated at 394 μmol/mol. The carbon content of the leaves was greater at the higher CO 2 concentrations; however, there was no difference in the C content of the stems and roots. The nitrogen content of the leaves, stems and roots were lower in the environments with higher CO2 concentrations. The results show that an increased CO2 concentration can reduce the severity of Ceratocystis wilt and stimulate the growth of Eucalyptus clonal plantlets. © 2013 Australasian Plant Pathology Society Inc. Source

Higashikawa F.S.,Federal University of Lavras | Silva C.A.,Federal University of Lavras | Bettiol W.,Embrapa Environment
Revista Brasileira de Ciencia do Solo | Year: 2010

Due to human activity, large amounts of organic residue are generated daily. Therefore, an adequate use in agricultural activities requires the characterization of the main properties. The chemical and physical characterization is important when planning the use and management of organic residue. In this study, chemical and physical properties of charcoal, coffee husk, pine-bark, cattle manure, chicken manure, coconut fiber, sewage sludge, peat, and vermiculite were determined. The following properties were analyzed: N-NH4 +, N-N03 -, and total concentrations of N, P, S, K, Ca, Mg, Mn, Zn, Cu, and B, as well as pH, Electrical Conductivity (EC) and bulk density. Coffee husk, sewage sludge, chicken manure and cattle manure were generally richer in nutrients. The EC values of these residues were also the highest (0.08 - 40.6 dS m-1). Peat and sewage sludge had the highest bulky density. Sodium contents varied from 0 to 4.75 g kg-1, with the highest levels in chicken manure, cattle manure and sewage sludge. Great care must be taken when establishing proportions of organic residues in the production of substrates with coffee husk, cattle or chicken manure or sewage sludge in the calculation of the applied fertilizer quantity in crop fertilization programs. Source

Kruk N.S.,Technical Institute of Aeronautic | Vendrame I.F.,Technical Institute of Aeronautic | Da Rocha H.R.,University of Sao Paulo | Chou S.C.,National Institute for Space Research | Cabral O.,Embrapa Environment
Theoretical and Applied Climatology | Year: 2010

The accurate estimate of the surface longwave fluxes contribution is important for the calculation of the surface radiation budget, which in turn controls all the components of the surface energy budget, such as evaporation and the sensible heat fluxes. This study evaluates the performance of the various downward longwave radiation parameterizations for clear and all-sky days applied to the Sertãozinho region in São Paulo, Brazil. Equations have been adjusted to the observations of longwave radiation. The adjusted equations were evaluated for every hour throughout the day and the results showed good fits for most of the day, except near dawn and sunset, followed by nighttime. The seasonal variation was studied by comparing the dry period against the rainy period in the dataset. The least square linear regressions resulted in coefficients equal to the coefficients found for the complete period, both in the dry period and in the rainy period. It is expected that the best fit equation to the observed data for this site be used to produce estimates in other regions of the State of São Paulo, where such information is not available. © 2009 Springer-Verlag. Source

Ghini R.,Embrapa Environment
Acta Horticulturae | Year: 2014

Climate change, intense globalization and the need to increase the sustainability of agricultural activity are major challenges for effective soil disinfestation. The impact of climate change on the soil biota, the geographical distribution of soilborne pathogens, and adaptation strategies are discussed. These challenges underscore the importance of adopting preventive measures in soilborne pathogens control and of holistic approaches that integrate physical, chemical and biological control. Source

Oelofse M.,Copenhagen University | Hogh-Jensen H.,University of Aarhus | Abreu L.S.,Embrapa Environment | Almeida G.F.,Federal University of Sao Carlos | And 4 more authors.
Agronomy for Sustainable Development | Year: 2011

Certified organic agriculture stipulates a range of principles and standards, which govern farmer practices. The recent global expansion of organic agriculture has raised new challenges for organic agriculture, particularly whether management practices in organic farms are subject to the forces of conventionalisation. We studied changes in agroecological practices in certified organic farms in China, Brazil and Egypt. The study takes departure in the conventionalisation hypothesis and the analysis is framed using organic and agroecological principles. The study focuses on agroecological design principles, inherent to organic agriculture, of diversity in crop production, pest, disease and weed management, and soil fertility management. The research design was as a multiple case study of five cases in China, Brazil and Egypt. We show that the adoption of organic agriculture has induced fundamental changes in organic farmer management practices, although agroecological practices of organic farmers do not fulfil organic principles. The forces of conventionalisation exert a strong influence on changes in organic farmer practices. Organic 'niche' market crops with a high-value influence organic farmers' management decisions, particularly regarding the prioritisation of diversity in the cropping systems for agroecological purposes. The farming systems have therefore not undergone major changes of their cropping patterns. Furthermore, there was a general heavy reliance upon input substitution for pest and soil fertility management. This study thus presents new data and a novel analysis of the implications at the farm scale of the global expansion of organic agriculture, and the influence of conventionalisation on farmers practices. © INRA and Springer Science+Business Media B.V. 2011. Source

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