Nutrição mineral da cana‑de‑açúcar irrigada com efluente de esgoto tratado, em área com aplicação de fosfogesso

O objetivo deste trabalho foi quantificar o aporte e a remoção de nutrientes em sistemas de cultivo  de cana‑de‑açúcar irrigados, ou não, com efluente de estação de tratamento de esgoto (EETE), com e sem  adição  de fosfogesso,  bem  como  avaliar  os  efeitos  desses sistemas  de  cultivo  no  estado  nutricional  das  plantas. Foram avaliados tratamentos sem irrigação e com irrigação a 100 e 150% da necessidade hídrica da  cultura. Os tratamentos com fosfogesso foram aplicados em área de terceiro corte, irrigada com EETE desde  o plantio. As  avaliações foram realizadas em duas safras. Os tratamentos não afetaram os rendimentos de  colmos. O tratamento com EETE e fosfogesso apresentou efeito sinérgico sobre o conteúdo de nitrogênio e de  enxofre nas plantas. O EETE beneficiou a nutrição das plantas quanto ao fósforo, mas não causou melhorias  na nutrição com potássio e enxofre. A nutrição com ferro, zinco e manganês não foi influenciada pelo aporte  desses micronutrientes pelo EETE. O  fósforo e o nitrogênio aportados na irrigação com EETE devem ser  considerados na recomendação de adubação. Porém, potássio, enxofre, ferro, zinco e manganês do efluente não  são fontes eficientes desses nutrientes para as plantas.

Toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis

The objective of this work was to evaluate the toxicity of synthetic and natural compounds on Tetranychus urticae and the predator Phytoseiulus macropilis. Mortality and growth rates of T. urticae and its predator were evaluated after applications of: abamectin, clofentezine, fenpropathrin, fenpyroximate, propargite, sulfur and spiromesifen, at their recommended concentrations; neem oils (Natuneem and Sempre Verde Killer Neem at 1%); and aqueous extracts at 10% of Dieffenbachia brasiliensis, Annona squamosa, Ruta graveolens, Agave angustifolia, Melia azedarach, Sonchus oleraceus, Mentha spicata x M. suaveolens, Allium cepa, Laurus nobilis, and Eucalyptus saligna. The acute toxicity and the influence of the compounds on the instantaneous growth rate of the mites were carried out in laboratory. Extracts of A. cepa, A. angustifolia, neem oil-based products, spiromesifen, propargite, fenpyroximate, abamectin and fenpropathrin caused mortality higher than 83% on T. urticae. Extract of A. angustifolia, Natuneem and clofentezine did not cause significant mortality rates on P. macropilis. Agave angustifolia and Natuneem did not affect significantly the growth rate of this predator. Propargite, fenpyroximate, abamectin, fenpropathrin, spiromesifen and extract of L. nobilis severely affected P. macropilis population.

Spatio-temporal variability of sugarcane yield efficiency in the state of Sao Paulo, Brazil

The objective of this work was to assess the spatial and temporal variability of sugarcane yield efficiency and yield gap in the state of Sao Paulo, Brazil, throughout 16 growing seasons, considering climate and soil as main effects, and socioeconomic factors as complementary. An empirical model was used to assess potential and attainable yields, using climate data series from 37 weather stations. Soil effects were analyzed using the concept of production environments associated with a soil aptitude map for sugarcane. Crop yield efficiency increased from 0.42 to 0.58 in the analyzed period (1990/1991 to 2005/2006 crop seasons), and yield gap consequently decreased from 58 to 42%. Climatic factors explained 43% of the variability of sugarcane yield efficiency, in the following order of importance: solar radiation, water deficit, maximum air temperature, precipitation, and minimum air temperature. Soil explained 15% of the variability, considering the average of all seasons. There was a change in the correlation pattern of climate and soil with yield efficiency after the 2001/2002 season, probably due to the crop expansion to the west of the state during the subsequent period. Socioeconomic, biotic and crop management factors together explain 42% of sugarcane yield efficiency in the state of Sao Paulo.

Selection of early-maturing sweet orange cultivars by performance indexes

The objective of this work was to select adequate early-maturing sweet orange cultivars for the fresh fruit market and for industrial processing using performance indexes. Performance indexes for citrus were established from data collected in an experiment carried out in the southwest region of the state of Sao Paulo, involving 12 early-maturing sweet orange cultivars. New results were obtained by identifying cultivars with superior characteristics. In a comparison with 'Hamlin' sweet orange, a standard early-maturing cultivar, 'Valencia 2' and 'Salustiana' were considered better materials for the fresh fruit market, whereas 'Westin' sweet orange was identified as a superior cultivar for orange juice processing.

Selenate and selenite on yield and agronomic biofortification with selenium in rice

The objective of this work was to evaluate the effect of doses of selenate and selenite on rice (Oryza sativa) biofortification with Se, as well the influence of these forms of Se in the levels of P, S, Fe, and Zn in grains. The experiment was conducted in a greenhouse, in pots with 4 dm(3) of a sandy clay loam Latosol, with medium texture, in a 5x2 factorial arrangement with five doses of Se (0, 0.75, 1.50, 3.0, and 6.0 mg dm(-3)) and two forms of Se (selenate and selenite). Selenate provided greater efficiency of root uptake of Se, plant-use efficiency, translocation from roots to shoots, and content of this element in rice grains. The application of Se during fertilization influences the levels of P, S, and Zn, but does not affect those of Fe in rice grains.

Yield and chemical properties of rubber of Hevea clones according to phenological stages

The objective of this work was to evaluate the yield performance and macronutrient content of rubber extracted from four Hevea brasiliensis clones, under different tapping systems and plant phenological stages. The experiment was carried out in the 2010 and 2011 crop seasons, in a split-plot randomized complete block design, with four replicates. The main treatments - GT 1, PB 235, IAN 873, and RRIM 600 clones - were allocated in the plots, and the secondary treatments, which were the tapping systems 1/2S d/2, 1/2S d/4 ET 2.5%, and 1/2S d/7 ET 2.5%, were allocated in the subplots. The analyzed variables were natural rubber yield and macronutrient contents. Samples of natural rubber were obtained in the leaf development, mature leaf, and leaf senescence phenological stages. Rubber yield and its macronutrient contents are more influenced by tapping practice than by genetic material in the restrictive phenological stages of foliage.

Functional diversity of bacterial genes associated with aromatic hydrocarbon degradation in anthropogenic dark earth of Amazonia

The objective of this work was to evaluate the catabolic gene diversity for the bacterial degradation of aromatic hydrocarbons in anthropogenic dark earth of Amazonia (ADE) and their biochar (BC). Functional diversity analyses in ADE soils can provide information on how adaptive microorganisms may influence the fertility of soils and what is their involvement in biogeochemical cycles. For this, clone libraries containing the gene encoding for the alpha subunit of aromatic ring-hydroxylating dioxygenases (alpha-A RH D bacterial gene) were constructed, totaling 800 clones. These libraries were prepared from samples of an ADE soil under two different land uses, located at the Caldeirao Experimental Station secondary forest (SF) and agriculture (AG)-, and the biochar (SF_BC and AG_BC, respectively). Heterogeneity estimates indicated greater diversity in BC libraries; and Venn diagrams showed more unique operational protein clusters (OPC) in the SF_BC library than the ADE soil, which indicates that specific metabolic processes may occur in biochar. Phylogenetic analysis showed unidentified dioxygenases in ADE soils. Libraries containing functional gene encoding for the alpha subunit of the aromatic ring-hydroxylating dioxygenases (ARHD) gene from biochar show higher diversity indices than those of ADE under secondary forest and agriculture.

'Syrah' vine on different rootstocks in winter cycle in the south of Minas Gerais State, Brazil

The objective of this work was to evaluate rootstock influence on agronomical, ecophysiological and qualitative characteristics of 'Syrah' vines managed by double pruning. Grapevines were grafted onto 'SO4', '110 Richter' and '1103 Paulsen' rootstocks and trained in vertical shoot position, with no irrigation. Ecophysiological characteristics, yield and composition of ripe grapes were evaluated in three crop seasons (2007, 2008 and 2010). Rootstocks did not affect pre-dawn water potential, with values close to -0.2 MPa, indicating that there was no soil water deficit at the end of ripening (June). There was also no significant effect of rootstocks on yield. The rootstock '1103 Paulsen' induced lower vegetative growth, lower photosynthetic rate and the best results for berry maturation for crop seasons with lower amount of rainfall. The rootstocks '110 Richter' and 'SO4' showed higher vigor under the meteorological conditions of 2010 and the greatest photosynthetic rates in the same period. Meteorological conditions significantly affected technological and phenolic ripeness, with best results observed in drought years. The '1103 Paulsen' rootstock provides better balance between vigor and yield, increasing grape quality.

Cellulose micro/nanofibres from Eucalyptus kraft pulp: Preparation and properties

There is growing interest in cellulose nanofibres from renewable sources for several industrial applications. However, there is a lack of information about one of the most abundant cellulose pulps: bleached Eucalyptus kraft pulp. The objective of the present work was to obtain Eucalyptus cellulose micro/nanofibres by three different processes, namely: refining, sonication and acid hydrolysis of the cellulose pulp. The refining was limited by the low efficiency of isolated nanofibrils, while sonication was more effective for this purpose. However, the latter process occurred at the expense of considerable damage to the cellulose structure. The whiskers obtained by acid hydrolysis resulted in nanostructures with lower diameter and length, and high crystallinity. Increasing hydrolysis reaction time led to narrower and shorter whiskers, but increased the crystallinity index. The present work contributes to the different widespread methods used for the production of micro/nanofibres for different applications. (C) 2012 Elsevier Ltd. All rights reserved.

Parametrização e avaliação do modelo DSSAT/Canegro para variedades brasileiras de cana-de-açúcar

O objetivo deste trabalho foi parametrizar e avaliar o modelo DSSAT/Canegro para cinco variedades brasileiras de cana-de-açúcar. A parametrização foi realizada a partir do uso de dados biométricos e de crescimento das variedades CTC 4, CTC 7, CTC 20, RB 86-7515 e RB 83-5486, obtidos em cinco localidades brasileiras. Foi realizada análise de sensibilidade local para os principais parâmetros. A parametrização do modelo foi feita por meio da técnica de estimativa da incerteza de probabilidade generalizada ("generalized likelihood uncertainty estimation", Glue). Para a avaliação das predições, foram utilizados, como indicadores estatísticos, o coeficiente de determinação (R2), o índice D de Willmott e a raiz quadrada do erro-médio (RMSE). As variedades CTC apresentaram índice D entre 0,870 e 0,944, para índice de área foliar, altura de colmo, perfilhamento e teor de sacarose. A variedade RB 83-5486 apresentou resultados similares para teor de sacarose e massa de matéria fresca do colmo, enquanto a variedade RB 86-7515 apresentou valores entre 0,665 e 0,873, para as variáveis avaliadas.

Performance of juveniles of Pseudoplatystoma fasciatum fed graded levels of corn gluten meal

The objective of this work was to evaluate corn gluten meal (CGM) as a substitute for fish meal in diets for striped catfish (Pseudoplatystoma fasciatum) juveniles. Eight isonitrogenous (46% crude protein) and isoenergetic (3,450 kcal kg(-1) digestible energy) diets, with increasing levels of CGM - 0, 6, 12, 18, 24, 30, 36, and 42%-, were fed to juvenile striped catfish (113.56 +/- 5.10 g) for seven weeks. Maximum values for weight gain, specific growth rate, protein efficiency ratio and feed conversion ratio, evaluated by polynomial quadratic regression, were observed with 10.4, 11.4, 15.4 and 15% of CGM inclusion, respectively. Feed intake decreased significantly from 0.8% CGM. Mesenteric fat index and body gross energy decreased linearly with increasing levels of CGM; minimum body protein contents were observed with 34.1% CGM. Yellow pigmentation of fillets significantly increased until 26.5% CGM, and decreased from this point forth. Both plasma glucose and protein concentrations decreased with increased CGM levels. The inclusion of 10-15% CGM promotes optimum of striped catfish juveniles depending on the parameter evaluated. Yellow coloration in fillets produced by CGM diets can have marketing implications.

Conductivity test in seeds of different passion flower species

The objective of this work was to evaluate the use of the conductivity test as a means of predicting seed viability in seven Passiflora species: P. alata, P. cincinnata, P. edulis f. edulis, P. edulis f. flavicarpa, P. morifolia, P. mucronata, and P. nitida. Conductivity of non?desiccated (control), desiccated, and non?desiccated cryopreserved seeds was determined and related to their germination percentage. The obtained results suggest that the electrical conductivity test has potential as a germination predictor for P. edulis f. flavicarpa seed lots, but not for the other tested species. Index terms: Passiflora, seed cryopreservation, seed desiccation, seed viability.

Avaliacao da produtividade de treze cultivares de campim buffel, na regiao semi-arida de Peranmbuco.

Para identificar as cultivares de capim buffel (Cenchrus ciliaris L.), melhor adaptadas a regiao semi-arida do Nordeste, foi conduzido um experimento no periodo de 1979/1983, no Campo Experimental de Manejo da Caatinga, do Centro de Pesquisa Agropecuaria do Tropico Semi-Arido (CPATSA-EMBRAPA), localizado em Petrolina, PE. Foram avaliadas treze cultivares de capim buffel, estabelecidas vegetativamente em parcelas de 4 m x 2,5 m. O delineamento experimental adotado foi o de blocos ao acaso com cinco repeticoes. Entre as cultivares de porte alto, destacou-se o Molopo com maiores produtividades (6.750 kg de materia seca/ha-ano), relacao colmo/folha e altura (106 cm). Comparativamente, a Biloela, que e atualmente a mais utilizada no CPATSA, apresentou menor altura (97 cm) e produtividade (5.455 kg de materia seca/ha-ano). Entre as cultivares de porte medio, observou-se a Gayndah com menor altura (77 cm) e a F1 Hibrido 171, com menor produtividade (3.745 kg de materia seca/ha-ano). Com relacao ao valor nutritivo, temos a Gayndah (12,43%) e o Molopo (9,51%), com maior e menor teor de proteina bruta, na materia seca, respectivamente.

Desempenho operacional de chassis porta-implementos para aracao e sulcamento.

O desempenho operacional dos tres tipos de chassi porta-implementos denominados Multicultor CPATSA, Multicultor CPATSA II e Policultor PONTAL foi avaliado para as operacoes de aracao e sulcamento no Campo Experimental do Bebedouro, do Centro de Pesquisa Agropecuaria do Tropico Semi-Arido, da Empresa Brasileira de Pesquisa Agropecuaria (CPATSA-EMBRAPA) Petrolina,PE. Os fatores quantificados foram a velocidade de operacao, tempo de giro e capacidade de campo, usando a mesma junta de bois e operador para cada chassi e operacao. A capacidade de campo variou de 436 a 742 m2/h por aracao e de 2.664 a 3.428 m2/h por sulcamento sem efeito significativo do tipo de chassi usado. As medias gerais de velocidade de operacao e tempo de giro foram de 0,926 m/s e 23 s, respectivamente, nao havendo diferenca significativa entre as operacoes, os tipos de chassis e varias etapas durante o trabalho diario. Os valores da capacidade de campo estimados pelas medias gerais de velocidade de operacao e o tempo de giro variaram em relacao aos valores observados durante a experimentacao, em media de + 15,2% para a aracao e - 15,67% para o sulcamento.

Climatic fluctuations and homogenization of Northeast Brazil using precipitation data.

Before using the basic precipitation data in any agroclimatic study to assess the productivity it is important to check the data series for homogeneity. For this purpose data of 105 locations for the period 1912-1981 over northeast Brazil were used. The preliminary study indicate nonhomogeneity in the time series during 1940's at few locations. The amplitude of variation of time series when taken as 10-year moving average show quite different for different regions. It appears that this amplitude is related to time of onset of effective rains in some extent. There is also great diversity in the fluctuations. They present a great regional diversity. Some diversity. Some of the data in the low latitudes indicate presence of four cycles namely 52, 26, 13 & 6.5. years. The 52-year cycle is also evident in the case of onset of southwest Monsoon over a low latitude zone (Kerala Coast) in India. In the case of south Africa the prominent cycles are 60, 30, 15 & 10 similar situation appears to be present in the higher latitudes of northeast Brazil.