Competição de variedades e híbridos de sorgo forrageiro (Sorghum vulgare Pers).

bitstream/item/126643/1/Competicao-de-variedades-e-hibridos-de-sorgo-e-forrageiro.pd

Potencial de solubilização de fósforo in vitro por isolados fúngicos do solo.

FertBio 2010

Prospecção de comunidades bacterianas do solo para o aproveitamento agrícola de fosfatos de rocha.

FertBio 2010

Biomassa de milheto em resposta à adubação com rochas fosfatadas associadas a microrganismos solubilizadores.

Fertbio 2012

Rock phosphate solubilizing microorganisms isolated from maize rhizosphere soil.

ABSTRACT - The selection of microorganisms capable of solubilizing phosphorus (P) from rock phosphates (RP) may contribute to reduce the dependence of imported fertilizers in grain crops, reducing the costs of agricultural production, and also the environmental impacts. This study tested 59 microorganisms (46 bacteria and 13 fungi) isolated from maize rhizosphere for solubilization of two RP, Araxá and Itafós phosphate in vitro (PA and PI, respectively). Among the 59 microorganisms solubilizing PA, 51% of the bacteria and 8% of fungi were classified as efficient. For PI, among 18 isolates, 50% of the bacteria and no fungi were efficient. There were significant differences in the availability of P among strains for both phosphates and most isolates evaluated for both types of rocks released more soluble P from PI than PA. Bacterial isolates CMSB58, CMSB32, CMSB20 and CMSB46 solubilized almost 20% of the P total in the PA and CMSB58, CMSB82, CMSB91 and CMSB48 solubilized more than 25% of the PI. The solubilizing activity of both phosphates was associated with a reduction of pH which suggests that the acidification of the culture medium can be one of the mechanisms involved in the solubilization of P. There was a dominance of the genera Burkholderia and Bacillus in the group of the most efficient bacteria and Talaromyces and Penicillium in the fungi group. The contribution of these strains to increasing the phosphorus nutrition of grain crops should be investigated further by in vivo experiments. RESUMO - A seleção de microrganismos capazes de solubilizarem fósforo (P) a partir de fosfatos de rocha (FR) pode contribuir para reduzir a dependência de fertilizantes importados em culturas de grãos, reduzindo os custos da produção agrícola e também os impactos ambientais. Este estudo avaliou 59 microrganismos (46 bactérias e 13 fungos), isolados da rizosfera de milho, quanto à solubilização de dois FR, Araxá e Itafós in vitro (FA e FI, respectivamente). Entre os 59 microrganismos solubilizadores de PA, 51% das bactérias e 8% dos fungos foram classificados como eficientes. Para FI, entre 18 isolados, 50% das bactérias e nenhum fungo foram eficientes. Houve diferença significativa na disponibilidade de P entre as cepas em ambos os fosfatos e a maioria dos isolados avaliados em ambos os tipos de rocha liberaram mais P solúvel de FI em comparação com FA. As bactérias CMSB58, CMSB32, CMSB20 e CMSB46 solubilizaram quase 20% do P total em FA e CMSB58, CMSB82, CMSB91 e CMSB48 solubilizaram mais que 25% de FI. A atividade de solubilização para ambos os fosfatos foi associada com a redução de pH, sugerindo que a acidificação do meio de cultura pode ser um dos mecanismos envolvidos na solubilização de P. Houve predominância dos gêneros Burkholderia e Bacillus no grupo de bactérias mais eficientes e Talaromyces e Penicillium no grupo dos fungos. A contribuição destes isolados na melhoria da nutrição de P em milho precisa ser investigada futuramente em experimentos in vivo

Beef cattle stocking rate, a key to the conservation of the pastoral system in Brazilian biomes.

Abstract: In Brazil, beef cattle are raised in predominantly extensive systems. The feeding base is represented by native and/or cultivated pastures. The latter may be in a well conserved state or may present some degree of degradation. The amount of animals per hectare, supported by the pasture by each time unit, is basically related to the pasture production. There is interaction between quality and production, and changes in these parameters are strongly affected by the stocking rate. Therefore, the adjustment in the stocking rate is the most important management factor and the main determinant of animal production and pasture composition. Municipal data from the 2006 agriculture and cattle raising business census were considered with the objective to analyze, by means of typologies, the use of pastoral areas in Brazil. In the census, the producers declared their pastoral areas according to the following classification: native pasture areas (PN), cultivated pasture areas in good conservation status (PC) and cultivated pasture areas with some degree of degradation (PCD). They also indicated the number of bovine in each type of pasture. The data were submitted to exploratory factorial analysis, with varimax rotation. The first two factors (extracted by main components) explained 0.83 of the (co)variance, and the estimate of the Kaiser-Mayer-Olkin (KMO) adequacy test was 0.76, which meant good adjustment of the variables selected. The commonalities of the variables selected, PN area; total pasture area (TP), bovines in PN (Bov_PN); bovines in PCD area (Bov_PCD); bovines in PC area (Bov_PC); bovines in total pasture area (Bov_APT); and the stocking rate (TxLota) were 0.65; 0.97; 0.77; 0.74; 0.79; 0.87; and 0.99, respectively. The first factor was associated with the variables PN, TP, Bov_PN, Bov_PCD, Bov_PC, and Bov_APT, which directs to the latent variable correlated to those municipalities with large pasture areas, in general, and also with the largest cattle population. The variable TxLota presented the most significant factorial load in the second factor, that is, all those municipalities with the greatest concentration of cattle per unit area are represented in the second factor. The municipalities that were best represented in factor_1 are different from the ones represented in factor_2. The non-parametric correlation between the classifications of the two groups of municipalities formed by the factorial scores in the first and the second factors is small (0,24). This indicates that the context of those municipalities with the highest stocking rate is a lot different from the ones with the largest areas and cattle herds. The application of livestock development policies in the different Brazilian biomes should take into account all the distinguishing features of the municipalities, regarding their context, especially the pasture areas and their vocation for primary livestock production.ICAS VI