Deficit irrigation is applied to several agricultural crops as a water-saving irrigation strategy. The tomato plant is sensitive to water stress; however, integration with biostimulant applications, based on seaweed extracts, could be a strategy for plants adapting to this abiotic condition. The objective of this study was to evaluate agronomic and quality aspects of tomato cultivated under deficit irrigation combined with Ascophyllum nodosum extract (ANE) application. The experiment was conducted using a completely randomized design with two water replacement levels, 70 and 100% of crop evapotranspiration (ETc), and five doses of ANE (0, 0.1, 0.2, 0.3 and 0.4%) applied via soil drench. The interaction between ANE and ETc was significant (p < 0.05) in terms of plant growth, physiological parameters, fruit yield, yield components and fruit quality. Results indicated that when the tomato plant is under deficit irrigation, a higher ANE dose is required to achieve better development when compared to the 100% ETc condition, where the dose is lower. Under deficit irrigation, the largest fruit yield was obtained with 0.3 and 0.4% ANE, and with 100% ETc, the largest fruit yield was obtained with 0.2% ANE. ANE applications were also effective in increasing plant height, stem diameter, plant biomass, leaf area, chlorophyll and relative water content. In addition, tomato quality was also favored under deficit irrigation and seaweed extract application. We conclude that ANE applications attenuate water deficit effects in tomato plants and provide a strategy to ameliorate tomato yield, tomato quality and water use in agriculture.
Os teores de pigmentos foliares estão diretamente relacionados com as condições de desenvolvimento da planta, sendo a determinação realizada por métodos diretos e indiretos. O trabalho teve como objetivo relacionar os valores do índice SPAD com o conteúdo de pigmentos foliares na cultura da ervilha. A determinação foi realizada em folhas de plantas em estágio reprodutivo, apresentando coloração variando de amarelada para verde escuro. A determinação indireta foi realizada com o equipamento SPAD 502 e a determinação direta por espectrometria utilizando acetona pura como extrator. Foi realizada análise descritiva, correlação e de regressão nos dados. O índice SPAD obtido variou entre 8,2 e 42,2. O teor absoluto de clorofila é elevado em valores de SPAD superiores, ajustado por modelos quadráticos. Foi obtido elevada correlação entre índice SPAD e pigmentos foliares (clorofilas a, b e totais) em folhas de ervilha.
O estudo teve como objetivo analisar o efeito do envelhecimento acelerado sobre a germinação de sementes de plantas daninhas. O experimento foi conduzido em laboratório, com delineamento inteiramente casualizado em esquema fatorial 4x5, sendo sementes quatro espécies (capim-carrapicho ( C. echinatus ), capim-colchão ( D. horizontalis ), caruru ( A. viridis ) e corda-de viola ( I. grandifolia)) cinco períodos de envelhecimento (0, 24, 36, 48 e 72 horas), e cinco repetições. As sementes foram envelhecidas à temperatura constante de 42±2°C. Foi analisado a condutividade elétrica, germinação e índice de velocidade de germinação. Os resultados foram descobertos uma análise de variância, análise de regressão e correlação. Houve incremento na condutividade elétrica pelo tempo de envelhecimento acelerado para capim-colchão, caruru e corda-de-viola. A germinação e o de velocidade de germinação índice mudanças expressivas para caruru e corda-de-viola. O tempo de envelhecimento acelerado reduz a germinação de caruru e eleva a germinação de corda-de-viola.
The objective of this study was to evaluate the effects of different levels of soil water replacement in each phenological stage of broccoli crop cultivated in a protected environment. The experiment was conducted in a protected environment in the municipality of Maringá, Paraná, Brazil. The experimental design used was in randomized blocks 4 by 3 having four levels of water replacement (55, 70, 85, and 100% of crop evapotranspiration) applied in three phenological stages (initial, intermediate, and final), and four replications. Productivity, inflorescence fresh matter, leaf fresh matter, stem fresh matter, number of leaves, stem diameter, inflorescence height, inflorescence diameter, plant height, leaf area, inflorescence dry matter, stem dry matter and leaf dry matter were evaluated. The data were submitted to variance analysis and compared by Scott-Knott test and regression analysis. Deficit of 30% of the ETc during the final stage of the broccoli crop, reduced productivity by 7%, on the other hand for the initial and intermediate stages, there was a drop of 30% and 23% respectively. The water deficit caused significant losses in broccoli production during the first phenological stages, but the final stage was less critical.
O conhecimento referente a demanda hídrica da cultura, assim como a compreensão de seu desenvolvimento vegetativo é a base para qualquer pesquisa científica agronômica. O presente trabalho teve por objetivo determinar a evapotranspiração, coeficiente da cultura, taxa de crescimento do fruto, caule e atividades fotossintéticas do meloeiro. O experimento foi conduzido em ambiente protegido no Centro Técnico de Irrigação (CTI) da Universidade Estadual de Maringá (UEM), em Maringá-Pr. O híbrido utilizado foi o melão Cantaloupe Torreon conduzido verticalmente. A irrigação foi realizada via gotejo com base na evapotranspiração acumulada. A evapotranspiração de referência foi estimada pelo método de Penman-Monteith-FAO utilizando dados de uma estação meteorológica automática e a evapotranspiração da cultura foi mensurada utilizando lisímetros. As aferições do colo da planta e do fruto em formação foram realizadas por paquímetro. As aferições do índice SPAD ocorreram na terceira folha da haste principal e na folha mais próxima do fruto. A demanda hídrica do meloeiro foi de 388,16 mm. Os valores do coeficiente da cultura obtidos foram: 0,95; 1,03 e 0,99 para os estádios inicial, intermediário e final. A taxa de crescimento do colo teve aumento de 7 mm até o 35° dia após o transplante. Em 14 dias o crescimento equatorial do fruto foi de 98 mm. O índice SPAD registrou máxima de 105 para a terceira folha e máxima de 112 para a folha do fruto.
The quality of cotton fiber is a fundamental criterion for determining the commercial value of the product, being influenced by the conditions of cultivation. The study aimed to evaluate irrigated and non-irrigated cultivation systems and the management of silicon fertilization on cotton fiber characteristics. The experiment was carried out in the field in Selvíria-MS, in the 2017/2018 agricultural crop. It was adopted a randomized block design, in a 2x6 factorial scheme, with two cultivationconditions (irrigated and rainfed) and six doses of Si (0, 50, 100, 150, 200 and 400 g ha-1), with four replications. Seeds of the genotype TMG 11 WS were used. Irrigation was carried out with sprinklers spaced at 6x6 m. The application of Si via leaf was carried out at 50 and 70 days after emergence. From thecotton fiber, the characteristics of length, micronaire, strength, uniformity, elongation, reflectance, yellowing, degree of leaves, impurity and impurity particles were analyzed. The data submitted to analysis of variance by the F test, the means compared for the cultivation condition, and regression analysis for the amount of Si. The cotton fiber in irrigated cultivation showed improvement in the characteristics resistance, reflectance and yellowing.The application of Si via leaf reduced the leaf grade in the cotton fibers.
The monitoring of grain and seeds characteristics is fundamental to maintain postharvest quality. Grain mass changes through CO2 levels monitoring can reduce the product deterioration by anticipating actions to maintain the grain mass quality. This study aimed to develop a CO2 monitoring system in stored grains/seeds and to analyze its efficiency. The analysis was performed in four crop species (brachiaria, sunflower, corn, and soybean) with different water content and sanity condition. The system hardware was composed of a controller micro board, CO2 sensor and data stored module. The system routine was developed in C++ language. The monitoring of CO2 and flammable gases was performed for system analysis and verification. The system monitoring developed showed efficiency in CO2 levels determination in stored grains/seeds and low-cost, being a viable and applicable tool aiming to the maintenance of postharvest quality.
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