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1.
Sci. agric ; 76(2): 179-189, Mar.-Apr. 2019. ilus, tab, graf
Artigo em Inglês | LILACS-Express | VETINDEX | ID: biblio-1497773

Resumo

Seedling production is an important step in the lettuce production system. However, there is a tendency to apply excessive irrigation at this stage. The aim of this study was to test the use of the Simplified Irrigation Controller (SIC) under two conditions: first, with the sensor installed in the substrate (measuring the soil water tension) and second, in the atmosphere (“atmospheric” - responding to vapor demand in the atmosphere) to control the irrigation of lettuce seedlings. The performance of the SIC was evaluated by monitoring plant traits. The lettuce seeds of the Regina cultivar were sown in styrofoam trays with commercial organic substrate. Both experiments were conducted under greenhouse conditions and evaluated under different SIC activation tensions. Shoot fresh weight and dry weight, height, number of leaves, leaf length, leaf area, water use efficiency (WUE) (ratio between the dry mass of plant produced by the volume of water applied), chlorophyll content, stomatal conductance and chlorophyll a fluorescence were assessed. In the experiment with the substrate sensor, the tension of 11.5 kPa caused death in 94 % of the seedlings and was disregarded in the statistical analysis. All biometric and physiological traits evaluated decreased as the SIC tensions increased. Thus, tensions of 4.0 (substrate sensor) and 3.5 kPa (atmospheric sensor) showed greater potential for producing vigorous seedlings, with WUE average values of 1.86 and 1.37 g L−1, respectively. Cultivation of lettuce seedlings proved viable under both conditions when the SIC was used, with the emergence of a number of practical advantages of the atmospheric sensor over the substrate one.

2.
Sci. agric. ; 76(2): 179-189, Mar.-Apr. 2019. ilus, tab, graf
Artigo em Inglês | VETINDEX | ID: vti-740867

Resumo

Seedling production is an important step in the lettuce production system. However, there is a tendency to apply excessive irrigation at this stage. The aim of this study was to test the use of the Simplified Irrigation Controller (SIC) under two conditions: first, with the sensor installed in the substrate (measuring the soil water tension) and second, in the atmosphere (“atmospheric” - responding to vapor demand in the atmosphere) to control the irrigation of lettuce seedlings. The performance of the SIC was evaluated by monitoring plant traits. The lettuce seeds of the Regina cultivar were sown in styrofoam trays with commercial organic substrate. Both experiments were conducted under greenhouse conditions and evaluated under different SIC activation tensions. Shoot fresh weight and dry weight, height, number of leaves, leaf length, leaf area, water use efficiency (WUE) (ratio between the dry mass of plant produced by the volume of water applied), chlorophyll content, stomatal conductance and chlorophyll a fluorescence were assessed. In the experiment with the substrate sensor, the tension of 11.5 kPa caused death in 94 % of the seedlings and was disregarded in the statistical analysis. All biometric and physiological traits evaluated decreased as the SIC tensions increased. Thus, tensions of 4.0 (substrate sensor) and 3.5 kPa (atmospheric sensor) showed greater potential for producing vigorous seedlings, with WUE average values of 1.86 and 1.37 g L−1, respectively. Cultivation of lettuce seedlings proved viable under both conditions when the SIC was used, with the emergence of a number of practical advantages of the atmospheric sensor over the substrate one.(AU)

3.
Ci. Rural ; 44(11): 1950-1955, Nov. 2014. graf, tab
Artigo em Português | VETINDEX | ID: vti-27971

Resumo

O presente estudo teve como objetivo comparar um sistema automático de baixo custo a outras duas técnicas de manejo (sistema Irrigás e tanque classe A) na cultura da alface (Lactuca sativa L.) com relação à operacionalidade dos sistemas, custo dos equipamentos, lâminas aplicadas e dados de produção da cultura. O cultivo foi desenvolvido num delineamento experimental de blocos ao acaso, com quatro tratamentos casualizados em seis blocos. Os tratamentos foram caracterizados pelo sistema Irrigás, tanque Classe A (TCA) e pelo uso de um acionador automático de baixo custo para irrigação (AAI), em duas tensões de água no solo (9,0kPa e 12,0kPa). Foram avaliados dados de lâmina aplicada, eficiência no uso da água e as variáveis de produção, área foliar, massa fresca e seca da parte aérea, diâmetro e altura da cabeça. Não houve diferença significativa entre os tratamentos para nenhuma das variáveis de produção avaliadas(P>0,05) e as lâminas totais referentes aos diferentes métodos de manejo foram próximas à evapotranspiração de referência (ETo) acumulada no período. A eficiência no uso da água nos tratamentos TCA, AAI/9kPa, Irrigás, AAI/12kPa foi, respectivamente, 241,4; 217,9; 205,5 e 267,1kg ha-1 mm-1, enquanto as produtividades foram respectivamente, 32,80; 28,86; 28,80 e 35,45Mg ha-1. Os resultados obtidos são próximos de valores reportados na literatura, permitindo concluir que as metodologias de manejo avaliadas foram eficientes para o cultivo de alface, e que, dessa forma, a escolha do método dependerá da disponibilidade de mão-de-obra e também do nível de treinamento do agricultor.(AU)


The objective of the present research was to compare an low cost controller with two other techniques of irrigation management, Irrigas system and Class A pan, in the cultive of lettuce (Lactuca sativa L.),concerning operability of systems, equipment costs, applied depths and crop yield data. The cultivation was developed in a randomized complete blocks design with four treatments randomized in six replicates. The treatments were characterized by the system Irrigás, Class A pan (TCA) and the use of automatic irrigation of low cost device (AAI) in two different soil water tensions (9.0kPa and 12.0kPa). Data of irrigation depth, water use efficiency and production variables leaf area, fresh and dry weight of shoots, diameter and height of the head were evaluated. There wasn't significant difference between treatments for any of the production variables evaluated (P>0.05) and total irrigation depths were related to different management practices and close to the evapotranspiration estimated reference (ETo) accumulated in the period. The water use efficiency in treatments TCA, AAI/9kPa, Irrigás, AAI/12kPa were, respectively, 241.4, 217.9, 205.5 and 267.1kg ha-1 mm-1, while the productivities were, respectively, 32.80, 28.86, 28.80 and 35.45Mg ha-1. The results obtained are close to values reported in the literature, allowing to conclude that the evaluated methodologies were efficient for growing lettuce and thus the method chosen would depend on the availability of skilled manpower and also of the level of farmer training.(AU)


Assuntos
Agricultura Orgânica , Lactuca , Irrigação Agrícola/métodos , Automação
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