Embrapa Cerrados


Embrapa Cerrados

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Leme E.M.C.,Herbarium Bradeanum | Ribeiro O.B.C.,Federal University of Viçosa | Miranda Z.J.G.,Embrapa Cerrados
Phytotaxa | Year: 2012

We describe and illustrate 10 new Dyckia species from the Brazilian states of Goiás, Mato Grosso, Mato Grosso do Sul, Minas Gerais and Paraná: Dyckia acutiflora, D. areniticola, D. formosensis, D. glabrifolia, D. gouveiana, D montezumensis, D. pottiorum, D. rondonopolitana, D. secundifolia and D. walteriana. The morphological affinities of the new taxa are also discussed. © 2012 Magnolia Press.

Vendrame P.R.S.,State University Londrina | Marchao R.L.,Embrapa Cerrados | Brunet D.,IRD Montpellier | Becquer T.,IRD Montpellier
European Journal of Soil Science | Year: 2012

Near-infrared reflectance spectroscopy (NIRS) has been accepted as a fast method to evaluate various soil constituents. However, very few studies have used NIRS as a predictor of the textural and mineralogical content of tropical soils. The objective of this study was to investigate the potential use of NIRS as a tool for assessment of diverse soil properties, with specific attention to the prediction of properties related to the mineralogy of a wide range of Latosols from the Cerrado region of central Brazil. The reflectance of the soil samples, 148 in total, taken from 0.0 to 0.2 and 0.6 to 0.8-m depth, was determined in the near-infrared region between 1100 and 2500 nm at 2-nm intervals with a NIRS spectrophotometer. Our results show that for soil sampling corresponding to a large-scale map and taking into account the variability of Latosols over a wide region, NIRS can predict most of the mineralogical properties of the Latosols accurately. Near-infrared spectroscopy did not predict most of the physico-chemical characteristics of soils accurately, in particular those that are largely dependent on agricultural practice, such as pH or CEC. However, the main characteristics that correspond to soil constituents (organic matter and clay content) were relatively well predicted. © 2012 The Authors. Journal compilation © 2012 British Society of Soil Science.

Oliveira C.M.,Embrapa Cerrados | Auad A.M.,Embrapa Gado de Leite | Mendes S.M.,Embrapa Milho e Sorgo | Frizzas M.R.,University of Brasilia
Crop Protection | Year: 2014

Among the various sectors of the Brazilian economy, agriculture plays a prominent role, generating jobs and income for the country. However, the agricultural sector faces systematic annual losses due to pests and diseases. The damage caused by insect pests is one of the primary factors leading to the reduced production of major crops. The study presented here estimates the production losses of major crops caused by insects and the economic impact related to the direct damage caused by insects, to the purchase of insecticides, and to medical treatment for humans poisoned by insecticides. The results indicate that insect pests cause an average annual loss of 7.7% in production in Brazil, which is a reduction of approximately 25milliontons of food, fiber, and biofuels. The total annual economic losses reach approximately US$ 17.7 billion. These results are important for government policies in the agricultural sector, as well as indicate the need for updated data regarding the losses caused by insects in Brazil and the need for systematic monitoring of these losses. © 2013 Elsevier Ltd.

Oliveira-Filho E.C.,Embrapa Cerrados
Bulletin of environmental contamination and toxicology | Year: 2014

Ecotoxicity tests are key to predict environmental hazards resulting from chemical and biological pesticides in non-target species. In order to assess the effects of microbial pesticides it is important to determine if they cause infection in test organisms. At present the microbial elimination rate or clearance is not included in ecotoxicological regulatory protocols. This study evaluated the elimination of Bacillus thuringiensis and Bacillus sphaericus from fish and snails, after 30 days' exposure to commercial formulations of such entomopathogens. Data obtained showed that in clean water the tendency to eliminate microbial agents from the body of the exposed organisms is gradual over time but after 7 days the fish and snails were free of the two tested Bacillus spp.

da Silva N.A.P.,Centro Universitario Of Brasilia | Frizzas M.R.,University of Brasilia | de Oliveira C.M.,Embrapa Cerrados
Revista Brasileira de Entomologia | Year: 2011

Seasonality in insect abundance in the "Cerrado" of Goiás State, Brazil. Many studies have provided evidence that tropical insects undergo seasonal changes in abundance and that this is partly due to alternation between the dry and rainy seasons. In the Brazilian "Cerrado" (savannah), this season alternation is particularly evident. The purpose of this work was to study the seasonal abundance of insects in a "Cerrado" area in the municipality of Pirenópolis, Goiás State, Brazil. The insects were captured fortnightly using a light trap between September 2005 and August 2006. The insects collected were separated at the order level and counted. Faunistic analysis was performed to select the predominant insect orders, a multiple linear regression to examine the relation between climatic variables (temperature and precipitation) with the abundance of insects and a circular distribution analysis to evaluate the existence of seasonality in the abundance of insect orders. A total of 34,741 insect specimens were captured, belonging to 19 orders. The orders with the greatest number of specimens were Hymenoptera (8,022), Coleoptera (6,680), Diptera (6,394), Lepidoptera (6,223), Isoptera (2,272), Hemiptera (2,240) and Trichoptera (1,967), which represent 97.3% of all the specimens collected. All the orders, except for Diptera, Isoptera and Trichoptera, showed a relationship with the climate variables (temperature), and all the orders, except for Diptera, presented a grouped distribution, with greater abundance in the transition from the end of the dry season (September) to the start of the rainy one (October/November). A discussion about seasonality on the abundance of the insects is presented.

Fernandes M.F.,Embrapa Coastal Tablelands | Barreto A.C.,Embrapa Coastal Tablelands | Mendes I.C.,Embrapa Cerrados | Dick R.P.,Ohio State University
Agriculture, Ecosystems and Environment | Year: 2011

We evaluated the short-term (three years) impact of agricultural practices (soil tillage methods, maize cropping systems, and Brachiaria fallow) on the physical and chemical aspects of soil quality (SQ) of a kaolinitic Kandiudalfs in Northeastern Brazil, and the correlation between SQ and microbiological variables. A forest site was also sampled as reference of undisturbed soil. SQ was evaluated by multivariate analyses of total and particulate organic matter carbon, cation exchange capacity, mean weigh diameter and percentage of water stable aggregates of soil samples (0-20. cm depth). Phospholipid fatty-acids were used to quantify microbial biomass (MB), fungi to bacteria ratio (F/B) and an indicator of bacterial stress (19:0cy/18:1ω7c), whereas microbial enzyme activity was determined by the hydrolysis of fluorescein diacetate (FDA). A gradient of SQ, described by increases in the values of physical and chemical variables, was observed according to the sequence: cropped areas, irrespective to the agricultural practices < Brachiaria fallow < forest. SQ was positively correlated with MB, F/B and FDA, and negatively with 19:0cy/18:1ω7c. F/B was more sensitive than SQ to the agricultural practices. In the short term, the physical and chemical aspects of the quality of a kaolinitic soil is restored by Brachiaria fallow, but is not affected by tillage methods or maize. +. pigeonpea intercropping. F/B ratio is a potential predictor of changes in the quality of kaolinitic soils in response to agricultural practices. © 2011 Elsevier B.V.

This study deals with the use of vegetal species by small farmers in the municipal district of Manacapuru, in the State of Amazonas. We used a formal questionnaire for participative interviews which took into consideration the entire agricultural property. Of the one hundred and seventy three species that we registered, the majority (101) presented medicinal use. Sixty-eight species are used for human nutrition and twenty-two for house building. Ninety-seven species (56.1%) come exclusively from domestic orchards; twenty-two (12.7%) exist only in the primary forest; and eighteen species (10.4%) originate from fallows. Some species can be found in different environments. Although the vegetation of the region under study is capable of providing farmers with necessary resources, their look for alternatives that might improve the quality of their lives. Planting fruit species is quite common and means both diversification and better food quality. It is however necessary to encourage planting native forest species. Knowledge and use of medicinal plants is always passed on from generation to generation by women.

de Figueiredo C.C.,University of Brasilia | Resck D.V.S.,Embrapa Cerrados | Carneiro M.A.C.,Laboratorio Of Solos
Revista Brasileira de Ciencia do Solo | Year: 2010

Soil organic matter can be analyzed on the basis of the different fractions. Changes in the levels of organic matter, caused by land use, can be better understood by alterations in the different compartments. The aim of this study was to evaluate the effect of different management systems on the labile and stable organic matter of a dystrophic Red Latosol (Oxisol). The following properties were determined: total organic C and total N (TOC and TN), particulate organic C and particulate N (POC and PN), organic C and N mineral-associated (MOC and NM) and particulate organic C associated with aggregate classes (POCA). Eight treatments were used: seven with soil management systems and one with native Cerrado as a reference. The experiment was designed to study the dynamics of systems of tillage and crop rotation, alternating in time and space. The experimental design was a randomized block design with three replications. The soil samples were collected from five depths: 0-5, 5-10, 10-20, 20-30 and 30-40 cm. Changes in organic C by land use occurred mainly in the fraction of particulate organic matter (> 53 mm). Proper management of grazing promoted increased levels of particulate organic matter by association with larger aggregates (2-8 mm), demonstrating the importance of the formation of this aggregate class for C protection in pasture.

Sano E.E.,Embrapa Cerrados | Rosa R.,Federal University of Uberlandia | Brito J.L.S.,Federal University of Uberlandia | Ferreira L.G.,Federal University of Goais
Environmental Monitoring and Assessment | Year: 2010

The Brazilian tropical savanna (Cerrado), encompassing more than 204 million hectares in the central part of the country, is the second richest biome in Brazil in terms of biodiversity and presents high land use pressure. The objective of this study was to map the land cover of the Cerrado biome based on the segmentation and visual interpretation of 170 Landsat Enhanced Thematic Mapper Plus satellite scenes acquired in 2002. The following land cover classes were discriminated: grasslands, shrublands, forestlands, croplands, pasturelands, reforestations, urban areas, and mining areas. The results showed that the remnant natural vegetation is still covering about 61% of the biome, however, on a highly asymmetrical basis. While natural physiognomies comprise 90% of the northern part of the biome, only 15% are left in its southern portions. Shrublands were the dominant natural land cover class, while pasturelands were the dominant land use class in the Cerrado biome. The final Cerrado's land cover map confirmed the intensive land use pressure in this unique biome. This paper also showed that Landsat-like sensors can provide feasible land cover maps of Cerrado, although ancillary data are required to help image interpretation. © 2009 Springer Science+Business Media B.V.

The objective of this work was to describe methods for molecular and morphological characterization of Helicoverpa armigera and to extend the pest occurrence record in Brazil. Moths were obtained from larvae collected in cotton, corn, and soybean crops, using light traps. Collections were done in the states of Bahia, Distrito Federal, Mato Grosso, and Paraná, Brazil. Identification was based on male genitalia and on the analyses of mitochondrial gene sequences of cytochrome B and of the cox1-tRNALeu-cox2 region. The male genitalia were compared with the morphological descriptions in the literature, and the gene sequences with the ones deposited at GenBank. Both analyses confirmed the presence of H. armigera in the collecting locations. The pest geographic range was expanded to the South region of the country.

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