Flávio Favaro Blanco

Yield and fruit quality of industrial tomato under saline irrigation

O tomate para processamento industrial e a hortalica mais importante da agroindustria brasileira. Poucas pesquisas tem sido desenvolvidas para avaliar a tolerância da cultura ao estresse salino. Neste estudo, foram testados os efeitos de cinco niveis de salinidade da agua de irrigacao (1, 2, 3, 4 e 5 dS m-1) e duas proporcoes equivalentes de Na:Ca:Mg (1:1:0,5 e 7:1:0,5) sobre a producao e a qualidade dos frutos de tomateiro tipo industrial, cultivar IPA 6. As mudas foram transplantadas em rhizotrons e o cultivo foi conduzido sob cobertura plastica ate a maturacao dos frutos. O volume de agua necessario para irrigacoes diarias foi determinado pela diferenca entre o volume aplicado e o drenado na irrigacao anterior. O aumento unitario da salinidade da agua acima de 1 dS m-1 reduziu a producao comercial e total em 11,9 e 11,0%, respectivamente, e aumentou a concentracao de solidos soluveis e a acidez titulavel dos frutos em 13,9 e 9,4%, respectivamente. O aumento da proporcao de sodio resultou em reducao da producao total e comercial, do numero de frutos comerciais e do rendimento de polpa. Aguas de salinidade moderada, com baixa concentracao de sodio, podem ser utilizadas na irrigacao do tomateiro industrial, sem perdas de rendimento no processamento.

Doses de N e K no tomateiro sob estresse salino: III. Produção e qualidade de frutos

The application of high doses of fertilizers could increase the tolerance of crops to salts by reducing the nutritional imbalance caused by salinity. In order to test this hypothesis, a study was conducted to evaluate the production and quality of tomato fruits, hybrid Facundo, irrigated with saline water, under different doses of N and K. The work was conducted in a greenhouse and the treatments were composed of the combination of three levels of N (7.5, 15.0 and 22.5 g per plant of N) and three levels of K (8, 16 and 24 g per plant of K2O) applied through drip fertigation, in the 3 x 3 factorial design, with five replications. Also the salts sodium chloride and calcium chloride were also added to irrigation water for obtaining an electrical conductivity of the irrigation water of 9.5 dS m-1. Effects of the treatments were not verified on the production components (yield, size and mean weight of fruits) nor on some parameters of the quality of the fruits (concentration of nutrients, soluble solids and titratable acidity), the concentration of K increased and the ratio Na/K reduced in the fruits with increasing dose of K. It was concluded that the application of high doses of N and K did not contribute to the increase the tolerance of tomato to salinity.

Características químicas e salino-sodicidade dos solos do Perímetro Irrigado Califórnia, SE, Brasil

The improper irrigation management may result in the accumulation of salts in the soil profile, which intensity depends on the irrigation water quality, the leaching fraction adopted and on the evapotranspiration demand of the region. The objective of the present study was to study the physical and chemical characteristics of the soils in the irrigated district of California, located in the northwest of the State of Sergipe. Thus, soil sampling were made in 54 lots, corresponding to 16.4% of the lots of this district. The highest salt and sodium concentrations occurred in the shallowest soil layer (0-0.2m), evidencing the lack of an appropriate irrigation management in order to control the salinity build up. The increasing of the soil pH was significantly correlated to the exchangeable sodium percentage, reaching values over 9.5. Significant positive correlations were observed between the electrical conductivity and the Ca and Mg content, indicating that salts of both ions could be accumulating in soil by the capillary rise of the water table, associated to the lack of leaching and drainage.

Crescimento e produção de tomate cereja em sistema hidropônico com rejeito de dessalinização.

Resumo - A produtividade agricola sustentavel e o maior desafio nas regioes aridas e semiaridas por causa da escassez de agua para irrigacao, sendo comum o uso de agua salobra para irrigacao. O objetivo desta pesquisa foi avaliar a resposta do tomate cereja (Lycopersicon esculentum L., cv. Samambaia) sob quatro niveis de salinidade da solucao nutritiva com adicao de rejeito salino em sistema de producao hidroponico. As plantas de tomate foram cultivadas em vasos com substrato de fibra de coco e irrigadas com solucoes nutritivas preparadas com agua de abastecimento e com aguas salinas preparadas diluindo-se agua de rejeito coletado em um dessalinizador a 75%; 50% e 25% e 0%, correspondendo a condutividades eletricas de 2,1; 3,55; 4,88, 6,02 e 6,96 dS m -1 , respectivamente. O delineamento experimental foi inteiramente casualizado, com 5 tratamentos (niveis de salinidade da solucao nutritiva) e quatro repeticoes. A altura e a massa seca das plantas reduziram com o aumento da salinidade da agua de irrigacao. O consumo hidrico da cultura foi influenciada pela adicao de rejeito salino na solucao nutritiva e a salinidade limiar, considerando-se a produtividade da cultura, ficou em torno de 3,51 dS m -1 . A adicao de ate 25% de rejeito de dessalinizador (diluicao de 75%) a solucao nutritiva permite o cultivo do tomate cereja, cv. ‘Samambaia’, sem haver reducao na produtividade. Palavras-chave - Lycopersicon esculentum Mill. Solucao nutritiva. Salinidade. Evapotranspiracao.

Concentração salina e fases de exposição à salinidade do meloeiro cultivado em substrato de fibra de coco

ABSTRACT – Scarcity of good water quality in semiarid region causes producers to use brackish water to prepare the nutrient solution. In order to investigate the use of brackish water in irrigation of greenhouse-melon (Cucumis melo L., cv. AF 015) grown in coconut fiber substrate, plants were irrigated with saltine nutrient solutions of electrical conductivities (ECs) of 1.1 (control), 2.5, 4.0 and 5.5 dS m -1 , applied during the phases of vegetative growth (10-30 days after transplanting, DAT), flowering (31-50 DAT) and fruiting and ripening (51-70 DAT). The design was completely randomized, with 12 treatments arranged in a 4x3 factorial design (salinity levels x exposure time of the salts), with three replications. There was a correlation in the reduction relative to each increased de EC s of the growth and yield variables of melon in function of ECs for each phase of exposure. The nutrient solutions prepared with brackish water can be used to grow melons in coconut fiber substrate with minimal reduction relative of mean fruit weight with increasing ECs applied during flowering.Index terms - Cucumis melo L. Nutrient Solution. Hydroponics.

Doses de N e K no tomateiro sob estresse salino: II. Crescimento e partição de matéria seca

The presence of certain nutrients in soil solution can stimulate the growth of plants when cultivated under saline stress. A study was conducted to evaluate the response of tomato (hybrid Facundo) to different doses of N and K under irrigation with saline water. The work was carried out in a greenhouse and the treatments consisted of the combination of three levels of N (7.5, 15.0 and 22.5 g per plant) and three levels of K (8, 16 and 24 g K2O per plant) applied by drip fertigation, in a 3 x 3 factorial scheme, with five replications. The salts sodium chloride and calcium chloride were also added to irrigation water for obtaining an electrical conductivity of the water of 9.5 dS m-1. Plant height, stem diameter, leaf area and the number of days for flowering were not affected by the levels of N and K, the levels of K affected the dry mass of stem plus clusters and total dry mass for the lowest levels of N. It was concluded that the application of high doses of N and K did not contribute to increase salt tolerance of tomato.

MECANISMOS CONTROLADORES DA QUALIDADE DAS ÁGUAS SUPERFICIAIS NA SUB-BACIA HIDROGRÁFICA DO RIO DAS COBRAS DO NORDESTE BRASILEIRO

Stream water quality is dependent on many factors, including the source and quantity of the streamflow and the types of geology and soil along the path of the stream. This study aims to evaluate the origin and the mechanisms controlling the input of ions that effect surface water quality in the sub-basin of the Rio das Cobras, Rio Grande do Norte state, Northeastern Brazil. Thirteen ponds were identified for study: three in the main river and ten in the tributaries between, thus covering the whole area and lithology of the sub-basin. The samples were collected at two different times (late dry and rainy periods) in the hydrological years 2009 and 2010, equating to total of four collection times. We analyzed the spatial and seasonal behavior of water quality in the sub-basin, using Piper diagrams, and analyzed the source of the ions using Guibbs diagram and molar ratios. With respect to ions, we found that water predominate in 82% sodium and 76% bicarbonate water (cations and anions, respectively). The main salinity control mechanism was related to the interaction of the colloidal particles (minerals and organic sediment) with the ions dissolved in water. Based on the analysis of nitrates and nitrites there was no evidence of contamination from anthropogenic sources.