602 research outputs found

    Yield of cotton cultivars under different irrigation depths in the Brazilian semi-arid region.

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    The objective of this study was to evaluate the effect of irrigation depths on seed cotton yield and water-use efficiency of cotton cultivars in the Brazilian semi-arid region. Field experiment was conducted during two consecutive years in the Apodi region, RN, using sprinkler irrigation. The experiment consisted of factorial combination in split-plots, composed of four irrigation depths (130; 100; 70 and 40% ETc and four cotton cultivars - FiberMax 993, BRS 286, BRS 336 and BRS 335), in randomized block design with 4 replicates. Data were evaluated by mean test (Tukey) and regression analysis. Considering the irrigation depths of 40% ETc, cotton yield was 48% lower compared to the higher irrigation depth (130% ETc). The higher water-use efficiency (0.69 kg m-3) was obtained with 70% ETc irrigation depth. The highest seed cotton yield was achieved with the higher water depth for all evaluated cultivars. Yield response factor (Ky) was equal to 0.632, 0.711, 0.784 and 0.858, for FiberMax 993, BRS 286, BRS 335 and BRS 336 cultivars, respectively. FiberMax 993 and BRS 286 cultivars presented the best performance, showing that they are more suitable for irrigated farming in the semi-arid region

    Canopy temperatures and accumulated degree days on cotton plants under water deficit.

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    Canopy temperature is one of the best integrators of plant health and has been successfully used for irrigation scheduling. Therefore, the objective of this study was to evaluate the canopy temperature of cotton plants under water stress at different stages of the crop cycle and to determine the accumulated degree days based on canopy temperature. It was applied water deficit periods of 15 days at the following phenological stages: First Square, First Flower, Peak Bloom and Opening Bolls and control treatment. Canopy temperature was obtained using SmartCrop® wireless infrared temperature sensors. The results showed higher canopy temperatures during water deficit periods. For water deficit periods, canopy temperature values were always above the optimum temperature for cotton metabolism. As a result of the stress caused by water deficit, cotton yield was significantly reduced, with the higher yield loses recorded when applied deficit occurred during flowering stages (beginning and peak). Accumulated degree days also varied according to water stress, with a shortened phenological cycle for treatments with water deficit in comparison to the control without stress. The period for fiber thickening was also influenced by the variation in canopy temperature due to water stress, which may reflect decline in fiber quality

    Devices for Screening and Monitoring of Tumors Based on Chemoresistive Sensors

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    Abstract In this work two devices are presented, named SCENT A1 (A1) and SCENT B1 (B1), composed of chemoresistive sensors. Such devices are capable of discriminating the different compositions of gas mixtures emitted by stools, for colorectal cancer screening (A1), and by blood, for tumors monitoring (B1), according to defined sampling protocols. Results have been acquired by a LabView® software and statistically treated (e.g. quadratic discriminant analysis, QDA) and show to be encouraging with an error of 5% for SCENT A1. Preliminary results of SCENT B1 proved to be promising. Further studies will be carried out for clinically validating the two devices

    Estudo de caso 7 - imagens aéreas na avaliação do vigor e estimativa de produtividade do algodoeiro na Fazenda Pamplona, Cristalina, GO.

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    O objetivo deste trabalho foi avaliar a capacidade de índices de vegetação obtidos através de imagens do satélite Sentinel-2, por imagens aéreas de alta resolução e imagens RGB obtidas em VANTs, na estimativa da produtividade do algodoeiro no cerrado de Goiás, monitorando o vigor das plantas através da variabilidade espacial de dois IVs, o MPRI (Modified Photochemical Reflectance Index) e o NDVI (Normalized Difference Vegetation Index) em diferentes estádios fenológicos
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