ABSTRACT In irrigated crops, salinity is the main cause of the reduction of growth and productivity, with damage of the variability according to the sensitivity of the crop. The objective of this work was to evaluate the growth, water consumption and production of basil cv. Toscano Folha de Alface under saline stress, in different frequencies of recirculation of the nutritive solution and hydroponic systems. The experimental design was a completely randomized design, in a factorial scheme 3 x 2 + 1, where the first factor represents the concentrations of NaCl (0, 40 and 80 mmol L-1) and the second factor the recirculation frequencies of the nutrient solution (4 or 6 hours) in a deep flow hydroponic system (DFT), and an additional treatment with nutrient solution in hydroponic laminar flow system (NFT). The water consumption, growth variables and phytomass production and growth rates were evaluated. Reducing the frequency of recirculation of the nutrient solution to six hours does not cause significant reductions in water consumption, growth, phytomass production and absolute growth rate of basil. The water consumption, growth, phytomass production and the absolute growth rate of basil reduced with the use of saline nutrient solution, 40 and 80 mmol L-1 NaCl. The choice of the DFT or NFT hydroponic system does not cause significant changes in the variables analyzed in basil, under the conditions studied.

O trabalho teve como objetivo avaliar modelos de calibração para dois tipos de guias de onda de TDR, referentes a dois equipamentos (Trase System e TDR 100), acopladas diretamente ao analisador de umidade ou a multiplexadores. Amostras de três tipos de solo foram acondicionadas em segmentos de tubos de PVC e saturadas. Dois tipos de guias de onda de três hastes, com capacitor e com resistor foram inseridas dentro de cada segmento de tubo com solo e conectadas a dois equipamentos de TDR, diretamente no testador de cabos ou via multiplexadores. Dados de umidade obtidos por gravimetria e da constante dielétrica foram tomados em cada coluna durante a secagem do solo da saturação até umidades próximas do limite inferior de disponibilidade de água por meio de leituras com as guias de onda conectadas ao testador de cabos e conectadas ao multiplexador. Um modelo polinomial cúbico foi ajustado aos dados da constante dielétrica do solo (épsilon) e da correspondente umidade (teta) e cinco modelos de determinação de q em função de e foram testados quanto ao desempenho. Os resultados mostraram que não houve diferença significativa na calibração das guias de onda com capacitor para uso com a TDR Trase System, considerando a conexão das guias ao analisador de umidade ou a multiplexadores. No caso da TDR 100, as guias de onda com resistor devem ser calibradas conforme o seu uso. O modelo cúbico foi o de melhor desempenho seguido pelo modelo de Roth que estimou, com boa exatidão, os valores da constante dielétrica e da umidade com a mais próximo de 0,5 para as guias de onda com capacitor que com as guias com resistor.

The study aimed at evaluating of calibration models for two kinds of TDR waveguides used with Trase System and TDR 100 equipments linked to the cable tester or the multiplexer. Disturbed samples of three soils were packed in PVC columns and, after soil saturation, two TDR waveguides of three rods with capacitor and with resistor were inserted into the soil columns. The waveguides were connected to two TDR equipments (Trase System and TDR 100), directly to the cable tester or a multiplexer. Soil water content data by gravimetry were collected during the drying process from saturation to values close to the lowest limit of water availability. The readings were performed with TDR probes connected to the cable tester and the multiplexer. A mathematical model was fitted to the bulk dielectric constant (e) and water content data (q) and the performance of five models to obtain q as a function of e was evaluated. Results showed that there was no significant difference between the TDR Trase System capacitor waveguide calibration connected either directly to the water content analyzer or the multiplexer channel. In case of TDR 100 using waveguides with resistor, the calibration has to be performed according to the connection of the waveguide to the water content analyzer or the multiplexer channel. The cubic calibration model performed best, followed by the Roth model, which estimated the values of bulk dielectric constant and water content well with a closer to 0.5 for waveguides with capacitor than for waveguides with resistor.

O sistema radicular de uma planta é responsável pela absorção de água do solo e deve ser considerado nos cálculos da quantidade de água necessária para irrigação. O trabalho teve por objetivo definir a distribuição do sistema radicular do mamoeiro irrigado por gotejamento e microaspersão em solo de Tabuleiro Costeiro do Recôncavo Baiano. Foram feitas duas trincheiras em diferentes posições relativas a duas plantas irrigadas por microaspersão e gotejamento superficial e enterrado a 0,25 m, com as linhas laterais junto à fileira de plantas, com dois gotejadores por planta, cada um a 0,40 m de distância das mesmas. Na microaspersão, usou-se um emissor para duas plantas, entre duas fileiras simples. As amostras de raízes foram extraídas em malha de pontos nessas trincheiras de forma a abranger uma seção completa do sistema radicular. As raízes foram separadas do solo e digitalizadas em computador, sendo as imagens processadas por um aplicativo computacional que estimou o comprimento total e o diâmetro médio das mesmas em cada posição no perfil. O sistema radicular ocupou maior volume de solo na microaspersão em relação ao gotejamento, com maior concentração das raízes na direção do microaspersor. A profundidade efetiva do sistema radicular do mamoeiro irrigado por gotejamento superficial ou enterrado foi de 0,45 m e na microaspersão variou de 0,15 m na direção perpendicular à fileira de plantas a 0,35 m entre a planta e o microaspersor.

The root system is responsible for water uptake and should be considered in irrigation water requirement calculations. The work had as objective to define papaya root distribution under sprayer and drip irrigation in a Tableland Coast Soil of Recôncavo Baiano. Two trenches were dug at different positions related to plants irrigated by sprayer and surface and buried drip irrigation. The lateral lines irrigation were set close to the plant row with two emitters per pant, each one at 0.40 m from plant. In case of sprayer, it was used one emitter per two plants located between two single rows. Root samples were collected from a grid of points in these trenches in order to cover a complete section of the root system. Roots were separated from soil material and digitized in a computer and the images were processed by a software that estimated the total root length and mean diameter at each position of the grid in the soil profile. Root system has occupied larger volume of soil under microsprinkler compared to under drip irrigation with larger root concentration in the direction of the emitter. The effective papaya root depth under surface or buried drip irrigation was 0.45 m and varied from 0.15 m between plant rows to 0.35 m between the plant and the emitter.