Distribuição do sistema radicular da cana-de-açúcar irrigada com efluente de esgoto doméstico por gotejamento subsuperficial

Irrigation with domestic sewage effluent (DSE) has been recommended by subsurface dripping, as it can obtain a high rate of irrigation efficiency and faster use of salts in comparison with other irrigation methods. The study aimed at evaluating the area, the length and the effective depth of the root system of sugarcane irrigated with DSE by subsurface drip system and with different irrigation rates at depths of 0.00-0.20, 0.20-0.40, 0.40-0.60 and 0.60-0.80m. The experiment was carried out in the municipality of Piracicaba, in the state of São Paulo (SP), Brazil, in a sugarcane area irrigated with DSE in a completely randomized blocks set up in furrows, with three replications and four treatments, which are: one area without irrigation (AWI) and three irrigated areas meeting 50% (T50%), 100% (T100%) and 200% (T200%) of the crop's water need between each round of irrigation. T100% and T200% provided smaller areas and lengths of roots in the two deepest layers, as compared to AWI and T50%, which stimulated the development of deeper roots due to the water stress. TWI, T100% and T200% presented 80% of the roots up to a depth of 0.40m and T50% treatment presented 76.43% of roots total.A irrigação com efluente de esgoto doméstico (EED) tem sido recomendada para aplicação por gotejamento subsuperficial, podendo-se obter elevados índices de eficiência de irrigação e mais rápido aproveitamento dos sais em comparação com outros métodos de irrigação. O trabalho objetivou avaliar a área de raiz, o comprimento e a profundidade efetiva do sistema radicular da cana-de-açúcar irrigada com EED aplicado por gotejamento subsuperficial e com diferentes lâminas de irrigação, nas camadas de solo de 0,00-0,20; 0,20-0,40; 0,40-0,60 e 0,60-0,80 m. O experimento foi realizado em Piracicaba-SP, numa área de cana-de-açúcar irrigada com EED, em um delineamento de blocos casualizados dispostos no esquema de faixas, com três repetições e quatro tratamentos, sendo estes: uma área sem irrigação (TSI) e três áreas irrigadas, atendendo a 50% (T50%), 100% (T100%) e 200% (T200%) da necessidade hídrica da cultura entre cada turno de rega. O T100% e o T200% proporcionaram menores áreas e comprimento de raízes nas duas camadas mais profundas, quando comparados ao TSI e ao T50%, que devido ao estresse hídrico, proporcionado à cultura, estimularam o desenvolvimento de raízes mais profundas. O TSI, T100% e T200% apresentaram 80% das raízes até 0,40 m e, nessa mesma profundidade, o tratamento T50% apresentou 76,43% do total de raízes.64765

The Genome of Anopheles darlingi, the main neotropical malaria vector

Anopheles darlingi is the principal neotropical malaria vector, responsible for more than a million cases of malaria per year on the American continent. Anopheles darlingi diverged from the African and Asian malaria vectors ∼100 million years ago (mya) and successfully adapted to the New World environment. Here we present an annotated reference A. darlingi genome, sequenced from a wild population of males and females collected in the Brazilian Amazon. A total of 10 481 predicted protein-coding genes were annotated, 72% of which have their closest counterpart in Anopheles gambiae and 21% have highest similarity with other mosquito species. In spite of a long period of divergent evolution, conserved gene synteny was observed between A. darlingi and A. gambiae. More than 10 million single nucleotide polymorphisms and short indels with potential use as genetic markers were identified. Transposable elements correspond to 2.3% of the A. darlingi genome. Genes associated with hematophagy, immunity and insecticide resistance, directly involved in vectorhuman and vectorparasite interactions, were identified and discussed. This study represents the first effort to sequence the genome of a neotropical malaria vector, and opens a new window through which we can contemplate the evolutionary history of anopheline mosquitoes. It also provides valuable information that may lead to novel strategies to reduce malaria transmission on the South American continent. The A. darlingi genome is accessible at www.labinfo.lncc.br/index.php/anopheles- darlingi. © 2013 The Author(s)

Processes and rates of formation defined by modelling in alkaline to acidic soil systems in Brazilian Pantanal wetland

International audienceWithin a soil system, it is generally difficult to relate the observed secondary phases and their spatial distribution to past or current processes. Geochemical modelling can help to identify present-days processes and to quantify formation rates if the system is sufficiently constrained. Here we used the PHREEQC model for this purpose, applying it to soil alkaline to acidic soil systems in the Nhecolândia area. A large amount of data was available, but scientific questions remained opened. We carried out a complementary field study to clarify a key point necessary for modelling, confirming the disconnection between two types of groundwater, perched, alkaline and deep, acidic. Our simulations showed that the observed soil system corresponds to the current biogeochemistry and that paleoclimatic genetic hypotheses are unnecessary. We found that the ridge soil formation rate ranges from 396 to 638 kg ha − 1 y − 1 , depending on hypotheses. We showed that the downslope soils act as buffers to store labile species during the dry season, allowing alkalinity to be maintained from one year to the next. At least 125 y were necessary to obtain downslope alkaline lakes, and this alkaline nature can quickly disappear after changing drainage conditions. We explained how hyperacidic horizons (pH 10) with a sharp contact. When correctly informed, geochemical modelling appeared as an effective tool to answer questions about soil processes

Performance Evaluation of a Portable Laser-Induced Fluorescence Spectroscopy System for the Assessment of the Humification Degree of the Soil Organic Matter

Laser-induced fluorescence spectroscopy (LIFS) has shown advantages for analyses of whole soil, providing results about chemical structure of soil organic matter (SOM) without the need for a chemical fractionating process; thus, allowing direct analysis of soils. Moreover, another advantage is the potential for the development of portable systems, which could be usable in field analyses. The aim of this paper is to evaluate the performance of a portable LIFS system to assess the humification degree (HD) of SOM. A good correlation (R > 0.8) was obtained for results (HD) achieved using the proposed portable system and a conventional fluorescence spectrometric method for humic acid. In addition, the results obtained using the portable LIFS system statistically agreed with the ones achieved using a benchtop LIFS system already described in the literature for such application (R = 0.953). Thus, the portable LIFS system constitutes an affordable option for the in situ characterization of SOM