Assessment of fungi in soils of sugarcane crops and their potential for production of biomass-degrading enzymes

Soil management practices are konwn to affect the biomass and enzyme activities of microbial soil communities. To assess whether burning of sugarcane prior to harvesting affects the community of soilborne fungi, we collected soil simples in two sites: burned sugarcane culture prior harvesting (BS) and non-burned sugarcane culture (NBS). A total of 75 filamentous fungal isolates were recovered from soils in both sites. Trichoderma was the most prevalent genus in both sites, followed by Fusarium, Cunninghamella and Aspergillus. The Sorensen's index (0.60) suggested a slight difference in fungi associated with both areas, with high number of fungal isolates found on BB soil. The abundance of Trichoderma isolates in NBS soil was higher than BS soil; however, the abundance of Fusarium, Aspergillus and Cunninghamella was higher in the latter type of soil. In addition, fungi isolated from BS soil showed the highest production of xylanase and laccase in comparision with fungi isolated form NBS soil. Our results indicate that the different types of sugarcane harvesting apparently did not interfere with the diversity of fungal communnities as revealed by culture-dependent methods. In addition, our data indicates the potencial of fungi from soils of sugarcane crops to produce relevant enzymes related to biomass conversion.

Physical and chemical matrix effects in soil carbon quantification using laser-induced breakdown spectroscopy

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Peat humic substances enriched with nutrients for agricultural applications: competion between nutrients and non-essential metals present in tropical soils

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Assessing land use by cattle in heterogeneous environments

The aim of this note is to describe preliminary results on assessment of land use by cattle, obtained in a pilot study using Geographic Information System (GIS). The research was carried out on a semi-natural pasture in Sweden, where the geographic positions of one cow were recorded during 25 consecutive days during summer. The cow, wearing a GPS collar, was integrated in a herd of 53 Hereford cattle. Each location point registered for the animal was considered as a sampling unit (N=3,097). The spatial distribution of ground declivity, water sources, cattle tracks, and classes of woody vegetation cover (forest, grassland with trees and open grassland) were recorded. The storage, processing and data analysis were carried out using the Idrisi and GS+ softwares. Three occupation zones were identified in function of the variation in the space used by the animal, which were occupied in a cyclical pattern; with the animal moving from one zone to another in cycles of five days. It was also clear that the cattle distribution in the area was neither random nor uniform, and it was affected by environmental characteristics that act as conditioners on its distribution. These preliminary results suggest that definition of zones of occupation and the environmental conditioners are promising tools to understand the land use by cattle

Organização genômima e análise da expressão do gene hnRNP Q-like (Heterogeneous nuclear ribonucleoprotein A-like) retroinserido no cromossomo B de Astatotilapia latifasciata

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Contamination of wetland soils and floodplain sediments from agricultural activities in the Cerrado Biome (State of Minas Gerais, Brazil)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Phosphorus fractions in soils of the mangrove, restinga and Atlantic forest ecosystems from Cardoso Island, Brazil

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Available nitrogen and responses to nitrogen fertilizer in brazilian eucalypt plantations on soils of contrasting texture

Eucalyptus plantations have seldom responded to N fertilization in tropical and subtropical regions of Brazil. This implies that rates of N mineralization have been adequate to supply tree needs. However, subsequent crop rotations with low N fertilization may result in declining concentrations of organic and potentially mineralizable N (N-0), and consequent loss of wood productivity. This study investigated (a) in situ N mineralization and N-0 in soils of eucalypt plantations in Sao Paulo state, Brazil; (b) tree growth responses to N fertilizer applied 6-18 months after planting; and (c) the relationships between N-0,N- other soil attributes and tree growth. We established eleven N fertilizer trials (maximum 240 kg ha(-1) of N) in E. grandis and E. grandis x urophylla plantations. The soil types at most sites were Oxisols and Quartzipsamments, with a range of organic matter (18 to 55 g kg(-1)) and clay contents (8% to 67%) in the 0-20 cm layer. Concentrations of N-0 were measured using anaerobic incubation on soil samples collected every three months (different seasons). The samples collected in spring and summer had N-0 140-400 kg ha(-1) (10%-19% total soil N), which were best correlated with soil texture and organic matter content. Rates of in situ net N mineralization (0-20 cm) ranged from 100 to 200 kg ha(-1) year(-1) and were not correlated with clay, total N, or N-0. These high N mineralization rates resulted in a low response to N fertilizer application during the early ages of stand growth, which were highest on sandy soils. At the end of the crop rotation, the response to N fertilizer was negligible and non-significant at all sites.

Management Impacts on Soil Organic Matter of Tropical Soils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Tropical soils with high aluminum concentrations cause oxidative stress in two tomato genotypes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Convenient synthesis of ketal derivatives from cubebin using amberlite as heterogeneous catalyst

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modeling the formation and propagation of desiccation cracks in soils

The problem of desiccation cracks in soils has received increasing attention in the last few years, in both experimental investigations and modeling. Experimental research has been mainly focused on the behavior of slurries subjected to drying in plates of different shapes, sizes and thickness. The main objectives of these studies were to learn about the process of crack formation under controlled environmental conditions, and also to better understand the effect of different factors (e.g. soil type, boundary conditions, soil thickness) on the morphology of the crack network. As for the numerical modeling, different approaches have been suggested lately to describe the behavior of drying cracks in soils. One aspect that it is still difficult to describe properly is the crack pattern observed in desiccated soils. This work presents a novel technique to model the behavior of drying soils. The crack patter observed in desiccation tests on circular plates are simulated with the main objective of predicting the effect of soil thickness on crack pattern. Good agreement between experimental results and model prediction are observed.

Cooperative effects of H+ and H- hydrido carbonyl ruthenium derivatives; role of homogeneous and heterogeneous protonic and lewis acids in catalytic hydrocarbonylation reactions

The role played by H+ hydrido iodocarbonyl and H- hydrido carbonyl ruthenium catalysts in the different catalytic steps of hydroformylation and hydroesterification of olefins, and in the homologation of alcohols has been investigated. The H- hydrido carbonyl species are mainly involved in the activation of olefins and in the hydrogenation of the acyl intermediates to aldehydes and alcohols, whereas the H+ hydrido iodocarbonyl derivatives are involved in the activation of alcohols and other oxygenated substrates, and in their carbonylation to esters. The cooperation between the two species, possible under particular reaction conditions, results in an improvement of the selectivity towards homologation (carbonylation plus hydrogenation) products. Heterogeneous Lewis acid promoters, easily recyclable from the reaction mixture, have also been successfully used in the hydrocarbonylation of alcohols, resulting in an increase of the carbonylation and homologation products. A reaction pathway in agreement with the experimental results is discussed. © 1989.

Comparative morpho-physiology of the metapleural glands of two Atta leaf-cutting ant queens nesting in clayish and organic soils

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)