1,705 research outputs found

    Use and management of pasture in the cerrado biome: Impacts on aggregation of an oxisol.

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    The objective of this study was to evaluate the physical quality of a dystrophic Oxisol in the Cerrado biome, by means of its aggregation, after 19 years of use and management with pasture. The treatments were soil with natural vegetation (CERR); and soil with Brachiaria decumbens cultivar Basilisk pasture, under the following four types of management: soil with maintenance-level fertilization, every two years, and with legumes (PAML); soil with maintenance-level fertilization, every two years (PAM); soil with fertilization only at implantation (PAI); and soil with degraded pasture without fertilization (PD). In November 2012, after 19 years of land use in the treatments, soil samples were collected at four locations per plot, and at two depths, 0 to 10 and 10 to 20 cm. The study evaluated the size distribution of air-dried aggregates and the distribution of water-stable aggregates, determining the water-stable weighted mean diameters (WMDws), the efficiency ratio of aggregates (ERA) and organic matter content of soil. The management of grassland with fertilizer favors the formation of larger aggregates in the soil, as well as WMDsw, ERA and the content of organic matter, improving soil physical quality, both in the 0 to 10 cm and in the 10 to 20 cm layer. Impacts on soil aggregates caused by the removal of native vegetation can be improved with the use of soil under pasture and managed with fertilization in the 10 to 20 cm layer

    Plantios de enriquecimento em florestas de produção no Acre.

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    Por meio de procedimentos e técnicas de restauração que considerem a escolha apropriada das espécies (principalmente quanto às características econômicas e ambientais), florestas exauridas de espécies comerciais podem ser conduzidas de maneira a reverter, ou minimizar, os efeitos da exploração seletiva que modificou sua estrutura original. Além disso, é fundamental que a condução posterior aos procedimentos de restauração seja feita de modo a garantir a sustentabilidade das espécies em florestas de produção. Este trabalho objetiva descrever os métodos utilizados, as etapas iniciais de implantação, a definição de espécies aptas e os resultados preliminares de plantios de enriquecimento com espécies florestais madeireiras de alto valor comercial em áreas de florestas destinadas à produção sustentável (manejo florestal) localizadas nos municípios de Xapuri, Brasileia e Rio Branco, no Estado do Acre. As ações aqui descritas são componentes de um projeto de pesquisa conduzido pela Embrapa Acre que tem como principal objetivo desenvolver procedimentos técnicos voltados à mitigação dos processos de escasseamento e ameaça de espécies madeireiras importantes por meio da restauração florestal. Tais procedimentos se destinam à transferência ao público afim, em especial, ao setor produtivo florestal do Acre e região.bitstream/item/99025/1/24929.PD

    Identificação de deficiências minerais de bovinos na microrregião Alto Purus-Acre.

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    A Unidade de Execução de Pesquisa de Âmbito Estadual - UEPAE/Rio Branco, vem desenvolvendo estudos com os objetivos de identificar as deficiências minerais de bovinos na microrregião Alto Purus-Acre, determinando as interrelações entre os níveis de minerais no solo, nas forrageiras e nos tecidos animais durante as estações chuvosa e seca.bitstream/item/145816/1/1097.pd

    Composição mineral de maçãs 'Gala' produzidas em Vacaria-RS e São Joaquim-SC na safra 2012/13.

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    Este trabalho teve por objetivo determinar a composição mineral de frutos de macieira da cultivar Gala, produzidos em Vacaria-RS e São Joaquim-SC, na safra 2012-2013

    A new baculovirus isolate that does not cause the liquefaction of the integument in Spodoptera frugiperda dead larvae.

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    The large-scale production of Baculovirus to control fall armyworm, Spodoptera frugiperda, presents many limitations. The most important limiting factor is that the baculovirus, which infects fall armyworm, causes liquefaction of the integument immediately after death. This disruption of the integument difficultates the large scale production because dead insect must be frozen before being harvested. This fact implies in high lab work need, increasing the cost of the biopesticide. This problem was overcome by the discovery of a new baculovirus nucleopolyhedrovirus (NPV) isolate in Cascavel/PR, that doesn?t cause liquefaction of the integument (isolate 6NR) immediately after the insect death. This is an extremely important factor in a large-scale baculovirus production. In addition, mortality caused by isolate 6NR on 6-day-old-larvae was above 93% (SEM=0.7%), the average weight dead larva was 116.21 mg (SEM=22.9), the larval equivalent and weight equivalent/ha were 15.04 g (SEM=1.2) and 140.32 larvae (SEM=20.1), respectively

    Estimativas de parâmetros genéticos via REML/BLUP para o melhoramento intrapopulacional de Platonia insignis Mart.

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    The aim of this study was to estimate genetic parameters to support the selection of bacuri progenies for a first cycle of recurrent selection, using the REML/BLUP (restricted maximum likelihood/best linear unbiased prediction) procedure to estimate the variance components and genotypic values. Were evaluated twelve variables in a total of 210 fruits from 39 different seed trees, from a field trial with an experimental design of incomplete blocks with clonal replies among subplots. The three variables related with the fruit development (weight, diameter, length) showed strong correlation, and where fruit length showed higher heritability and potential to be used for indirect selection. Among the 39 progenies evaluated in this study, five present potential to compose the next cycle of recurrent selection, due they hold good selection differential either to agrotechnological variables as to development of bacuri fruit

    Bioprospection and extracts chemical characterization of plant growth promoting bacteria and antagonists of agricultural pests.

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    In the present work, 11 bacteria previously identified as fungal pathogen antagonist were used. For the chemical characterization of potential antifungal metabolites, a screening was first performed through co-cultures to identify the best antagonists against seven agricultural pathogens. Of the 77 combinations tested, at least 44 (57%) showed potential antagonism, especially CMAA1398 and CMAA1399, inhibiting all tested fungi strains. Now, the CMAA1399 extract is under characterization by MS
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