No abstract

RESUMO:Visando à otimização do uso da água na produção de alimentos, este artigo teve como objetivo avaliar o desempenho da TDR e de um acionador automático para irrigação na produção da alface em solos com diferentes doses de um polímero hidrofílico. Em casa de vegetação, foram realizados dois ensaios em vasos de 3 litros cultivados com alface. O primeiro foi realizado na primavera de 2011, utilizando 2 texturas de solo (arenosa e argilosa) e a presença/ausência do hidrogel. O segundo ensaio foi realizado no outono de 2012, utilizando 4 doses de hidrogel (0; 8; 16 e 24 g por vaso) no solo de textura arenosa. Aos 38 (2011) e 44 (2012) dias após o transplantio (DAT) das mudas, foram realizadas as colheitas e a avaliação das plantas cultivadas. O hidrogel não representou uma fonte de erros para o funcionamento da TDR, e o dispositivo acionador automático para irrigação respondeu adequadamente à presença do hidrogel nos solos com diferentes texturas. Em geral, foi verificada maior eficiência do uso da água nas plantas desenvolvidas na presença do hidrogel. As plantas cultivadas em solo com 16 g por vaso de hidrogel destacaram-se em massa seca e fresca da parte aérea. PALAVRAS-CHAVE: polímero hidrofílico, TDR, automação e gotejamento. LETTUCE GROWING UNDER AUTOMATED IRRIGATION AND HYDROGEL APPLICATIONABSTRACT: This paper aimed at evaluating the performance of a time domain reflectometry (TDR) and automation of an irrigation system to optimize water use in lettuce production in soils with different doses of hydrogel. For that, two greenhouse experiments were carried out with lettuce seedlings in 3-L pots. The first experiment was performed during the spring of 2011 using two soil textures (sandy and clayey) and presence or absence of hydrogel. The second one was made in the fall of 2012 using four doses of hydrogel (0, 8, 16 and 24 g per pot) in a sandy textured soil. The evaluations were carried out at 38 (2011) and 44 (2012) days after transplanting (DAT) of the seedlings. Results showed that hydrogel application did not affect the TDR performance. In addition, the automatic trigger device used for irrigation had adequate resposnses to hydrogel application in both soils. Overall, plants grew better in soils treated with hydrogel and the application of 16 g hydrogel per pot stood out since provided larger amounts of fresh and dry matter of plant shoot.

RESUMO O presen te 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 AAI/9kPa, Irrigás, AAI/12kPa foi, respectivamente, 241,4; 217,9; 205,5 AAI/9kPa, Irrigás, AAI/12kPa were, respectively, 241.4, 217.9, while the productivities were, respectively, 32.80, 28.86, 28.80 and 35.45Mg

The responses of oregano plants to water limitation from soil and seasonal phenological cycle are not fully understood yet. The aim of the present research was to help understanding the production of oregano essential oil and biomass facing soil water deficit, which was studied in different seasons. Oregano was subjected to drip irrigation, the water deficit being assessed in the vegetative and pre-flowering stages, as well as whole cycle analysis, through water matric potentials in the soil. The matric potential -60.8 kPa adopted in the irrigation handling during the oregano cultivation interval, led to higher essential oil content and yield. The same potential applied during the oregano pre-flowering stage resulted in the best mean of oregano fresh biomass production. The best dry biomass production was reached by using the matric potential -91.2 kPa in the oregano pre-flowering irrigation management. Water restriction in the soil throughout the entire phenological cycle favored essential oil production, whereas the water restriction during the pre-flowering stage enabled high oregano dry biomass production. The highest values for biomass and essential oil productions were reached for the oregano plants cultivated during spring/summer.

Baccharis trimera (Less.) DC (E1) and Baccharis crispa Spreng. (E2) possess potential antimicrobial and anti-inflammatory properties. Qualitative and quantitative information on seed germination on these species is scarce. The objective of this investigation was to establish a protocol for evaluating seed germination of E1 and E2 and to analice the scoring and curve fitting by the Germinator package, for different periods of germination were between 0.93 and 0.99. Both species showed differences in germinability and mean germination time, 27 days for E1 and 20 days for E2. The germination dispersion showed that E1 germination was homogeneous, with differences in growth pattern, whereas the results on germination of E2. The mean speed of germination determined with the experimental data was close to the values obtained by the Germinator package, with a maximum germination of more than 34%, proving that the software was efficient for evaluating germination.