948 resultados para Algas verdes


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The organic fertilizer can be a viable alternative in the production of forage grasses, however there is little information regarding doses and composition of the major organic fertilizers. The aim of this paper was to verify the influence of the different doses of organic compost produced from two types of poultry litter on the structural, morphogenetic and productive characteristics of Brachiaria brizantha cv 'Piatã'. The experiment was conducted in a greenhouse in a completely randomized design in a factorial scheme l with parcel subdivided in time. The parcels were composed by six treatments: two types of compost (poultry litter based in sugar cane and napier grass) in three doses (100, 200 and 300kg ha-1 equivalent N.) and the subparcels by the four different periods of cut. The composts were applied in a unique dose, after the uniformization cut, at the quantities: 11,36 and 11,83, 22,73 and 23,67, 34,09 and 35,50 g pot-1 for the poultry litter based in sugar cane and napier grass, respectively which are equivalent to the rates of 0, 100, 200 and 300kg ha-1 of N. The variables measured were: dry matter production (DMP), leaf appearance rate (LApR), phyllochron, leaf elongation dose (LER) and shoots elongation rate (SER), number of green leaves (NGL), final size of the leaf (FSL). No significant difference between the types of composts and in the interaction compost x doses was observed, thus, both could be used without the risk of loss in the use of the nutrients by the plants evaluated in the experiment. There was a significant difference between the DMP, LApR, phyllochron, LER, SER, NGL and FSL because of the increasing rates of nitrogen, followed by a linear model of prediction. The effect of the periods of slaughter was also observed, where the slaughters carried out in the summer presented a better performance over the morphogenetic and structural features evaluated.

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Urban homegardens are green areas of households within the city limits and they have the potential to provide families with a cheap alternative for diet improvement, and to complement the income of the families who sell cultivated products. This research analyzes the contributions of old urban homegardens on food consumption and household economy. Data related to homegardens composition were collected by interviews and by collecting cultivated plants. Diets were assessed through a retrospective method (last 24 hours food recall) and administered every two months, during a year, to include seasonal variations. The diet of the sampled population was found to be dependent on certain foods, indicating a narrow food niche (Levins index = 25.9; Levins standardized index = 0.23). Variations in interviewees' diet are related to the consumption of fruits and vegetables, which are partly supplied by homegardens. Spices and teas consumed were obtained from homegardens, revealing its importance in food consumption and health. Among the 98 species found in homegardens, only 38% appeared in the interviewees' diet, indicating an under-exploitation of these homegardens. Our study found that the main role of homegardens is to supply variation in the diet, contributing to the consumption of different types of products.

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AIM: In this study, we evaluated and compared community attributes from a tropical deforested stream, located in a pasture area, in a period before (PRED I) and three times after (POSD I, II, and III) a flash flood, in order to investigate the existence of temporal modifications in community structure that suggests return to conditions previous to the flash flood. METHODS: Biota samples included algae, macrophytes, macroinvertebrates, and fish assemblages. Changes in stream physical structure we also evaluated. Similarity of the aquatic biota between pre and post-disturbance periods was examined by exploratory ordination, known as Non-Metric Multidimensional Scaling associated with Cluster Analysis, using quantitative and presence/absence Bray-Curtis similarity coefficients. Presence and absence data were used for multivariate correlation analysis (Relate Analysis) in order to investigate taxonomic composition similarity of biota between pre and post-disturbance periods. RESULTS: Our results evidenced channel simplification and an expressive decrease in richness and abundance of all taxa right after the flood, followed by subsequent increases of these parameters in the next three samples, indicating trends towards stream community recovery. Bray-Curtis similarity coefficients evidenced a greater community structure disparity among the period right after the flood and the subsequent ones. Multivariate correlation analysis evidenced a greater correlation between macroinvertebrates and algae/macrophytes, demonstrating the narrow relation between their recolonization dynamics. CONCLUSIONS: Despite overall community structure tended to return to previous conditions, recolonization after the flood was much slower than that reported in literature. Finally, the remarkably high flood impact along with the slow recolonization could be a result of the historical presence of anthropic impacts in the region, such as siltation, riparian forest complete depletion, and habitat simplification, which magnified the effects of a natural disturbance.

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Intercropping could efficiently prevent soil nutrient losses caused by extensive agriculture. The present study aimed to assess the effect of green manure on the nutritional status of orange trees cultivar 'Pera' (Citrus sinensis (L.) Osbeck). The plants were grafted on 'Cravo' lime trees and were then planted in a 7x4m space. Four different treatments corresponding to the evaluated green manures were employed: jack bean (JB) (Canavalia ensiformis DC), lablab (LL) (Dolichos lablab L.), pigeon pea (PP) (Cajanus cajan L. Millsp), and Brachiaria (BQ) (Brachiaria brizantha Hochst ex A. Rich. Stapf) as control. The experimental design was in randomized blocks, in split-plot time, with six replicates, with four treatments (green manures) and two plants per evaluation. The nutritional status was assessed by using the DRIS method (Diagnosis and Recommendation Integrated System); the yield and the macro and micronutrient levels contained in green manures and in the control was also determined. The nutritional diagnosis indicated that, in the two years of experiment, plants treated with green manure showed better nutritional balance index compared to Brachiaria. This suggests that, over time, green manure can lead to better nutritional balance. Pigeon pea treatment showed the highest yields, compared to control, in the two evaluated crop cycles (2004/05 and 2005/06).

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Algae bloom is one of the major consequences of the eutrophication of aquatic systems, including algae capable of producing toxic substances. Among these are several species of cyanobacteria, also known as blue-green algae, that have the capacity to adapt themselves to changes in the water column. Thus, the horizontal distribution of cyanobacteria harmful algae blooms (CHABs) is essential, not only to the environment, but also for public health. The use of remote sensing techniques for mapping CHABs has been explored by means of bio-optical modeling of phycocyanin (PC), a unique inland waters cyanobacteria pigment. However, due to the small number of sensors with a spectral band of the PC absorption feature, it is difficult to develop semi-analytical models. This study evaluated the use of an empirical model to identify CHABs using TM and ETM+ sensors aboard Landsat 5 and 7 satellites. Five images were acquired for applying the model. Besides the images, data was also collected in the Guarapiranga Reservoir, in São Paulo Metropolitan Region, regarding the cyanobacteria cell count (cells/mL), which was used as an indicator of CHABs biomass. When model values were analyzed excluding calibration factors for temperate lakes, they showed a medium correlation (R²=0.81, p=0.036), while when the factors were included the model showed a high correlation (R²=0.96, p=0.003) to the cyanobacteria cell count. The empirical model analyzed proved useful as an important tool for policy makers, since it provided information regarding the horizontal distribution of CHABs which could not be acquired from traditional monitoring techniques.

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Pós-graduação em Agronomia (Agricultura) - FCA

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Evaluated the evapotranspiration (ETc) and the efficiency of water use (USA) by the fig tree 'Purple Valinhos' submitted to irrigation and mulching (bagacilho of sugar cane crushed) in the first production cycle, at conditions of Botucatu, St. Paul. We used the method of soil water balance and to obtain the reference evapotranspiration method was used Montheit FAO Penman 56. For the assessment of crop coefficients (kc) we adopted the following phenological distribution: phase 1 - between transplanting and 20% of the vegetative (DV), ii) phase 2 - 20 to 80% DV, and iii) phase 3 - fruiting. Observe the cumulative ETc 409.4 and 465.8 mm in 254 days after transplanting (DAT) and averages of 1.47 and 1.67 mm day(-1), with and without mulching (CC and SC). The crop coefficients (kc) mediums were 0.16, 0.43 and 0.49 for SC and 0.18, 0.44 and 0.50 for CC, in phases 1 and 3, respectively. The EUA values decrease with increasing the volume of water received and ranged between 1.65 and 3.32 kg of green figs per m(3) of water for irrigated SC and CC.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

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Pós-graduação em Estudos Literários - FCLAR

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Pós-graduação em Engenharia Mecânica - FEG

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Pós-graduação em Zootecnia - FCAV

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A fragmentação de habitats decorrente principalmente da expansão da agropecuária no Brasil, bem como o declínio observado em escala mundial dos polinizadores (abelhas em sua maioria), atestam a gravidade do problema ambiental que enfrentamos atualmente. Baixos níveis de polinização de plantas em geral podem ocasionar problemas econômicos na área da alimentação humana, visto que muitas espécies vegetais importantes para nosso consumo dependem das abelhas para sua reprodução e conseqüente formação de frutos. Assim, a execução de planos de manejo em áreas cultivadas, envolvendo medidas de proteção para polinizadores e que visem a manutenção de áreas verdes no entorno de plantações são importantes estratégias para amenizar o impacto que o homem exerce sobre a natureza. Nesse aspecto, esse estudo tratou de investigar a preferência alimentar de abelhas amostradas em flores de Solanum viarum Dunal e a biologia floral e sistema de reprodução nessa espécie. Os conhecimentos e informações obtidos a partir de trabalhos como esses compreendem uma parte essencial de planos de conservação para o grupo de polinizadores. S. viarum é uma solanácea ruderal, que ocorre em campos abertos e ambientes perturbados. Apresenta deiscência das anteras do tipo poricida, é auto-incompatível e possui grande atratividade para inúmeras espécies de abelhas vibradoras, como as dos gêneros Bombus, Exomalopsis e da Família Halictidae. De acordo com os presentes resultados, pode-se afirmar que S. viarum caracteriza-se como uma espécie potencialmente doadora de pólen para os polinizadores acima citados, e que seu plantio e manejo controlados ao redor de cultivos agrícolas, juntamente com outros tipos vegetais, pode aumentar a densidade de abelhas no entorno dessas áreas e a rentabilidade de tais cultivos