Effect of regulated deficit irrigation (RDI) on the vegetative growth of pear variety Triunfo de Viena (Pyrus communis L.) / Efecto del riego deficitario controlado (RDC) en el crecimiento vegetativo del peral variedad Triunfo de Viena (Pyrus communis L.)

ABSTRACT One of the consequences of a water deficit in the vegetative growth is the modification of the plant vigor, which determines the extent and the rate of growth and lengthening in shoots, which, in this phase, is more important than fruit growth, which is very slow in terms of dry mass accumulation. The objective of this research was to determine the effect on the vegetative growth of the pear variety Triunfo de Viena (Pyrus communis L) of regulated deficit irrigation (RDI), which was compared with a control irrigated at 100% crop evapotranspiration (ETc). The irrigation treatments consisted of the application of watering regimes of 74 and 48% ETc in treatment T2 and 60 and 27% ETc in treatment T3 in 2014 and 2015, respectively, during the period of rapid fruit growth with the same watering regime used in T1 (control) applied during the rest of the season. The irrigation reduction used in T2 and T3 represented water savings of 26% and 40% in 2014 and 52% and 73% in 2015, respectively. In the deficit treatments, there were no significant differences with respect to the control for the length, or absolute and relative growth rates (AGR and RGR) of the shoots. The weight of the wood from the fructification pruning had a significant difference between T3 and the control.

RESUMEN Una de las consecuencias del déficit hídrico en el crecimiento vegetativo es la modificación del vigor de la planta, que determina la extensión y el ritmo de crecimiento y de alargamiento de los brotes que, en esta fase, es más importante que el crecimiento del fruto, el cual, es bastante lento, en términos de acumulación de masa seca. El objetivo de esta investigación fue determinar el efecto sobre el crecimiento vegetativo del peral variedad Triunfo de Viena (Pyrus communis L.) del riego deficitario controlado (RDC), que se comparó con un Control, regado al 100%, de la evapotranspiración del cultivo ETc. Los tratamientos de riego consistieron en la aplicación de láminas de agua, correspondiente al 74 y 48% de la ETc, en el tratamiento T2 y 60 y 27% de la ETc, en el tratamiento T3, en 2014 y 2015, respectivamente; durante el periodo de crecimiento rápido del fruto, mientras el resto de la temporada, todos se regaron igual que el T1 (control). La reducción de la lámina de riego en T2 y T3, durante este periodo, representó un ahorro de agua de 26 y 40%, en 2014 y 52 y 73%, en 2015, respectivamente. En los tratamientos deficitarios no hubo diferencias significativas respecto al control, en el diámetro, la longitud, la tasa absoluta y la relativa de crecimiento (TAC y TRC) de brotes. En la masa de madera correspondiente a la poda de fructificación, se presentó diferencia significativa, entre el T3 y el control.

Cinética da secagem de amostras de pera com geometrias distintas em secador solar (Pyrus L. ) / Drying kinetics of pear samples with different geometries in solar dryer

O objetivo do estudo foi realizar a desidratação de amostras de pera através da secagem solar e obter as respectivas curvas de secagem. As amostras foram submetidas à desidratação em dois tipos de geometrias, circulares com 1cm de espessura e em cubos com 1cm de comprimento. Os dados experimentais das curvas de secagem para as duas condições foram ajustados ao modelo matemático de secagem baseado na Segunda Lei de Fick. Os resultados mostram que a umidade do fruto é de aproximadamente 85%. As amostras apresentaram peso constante a partir de 18 horas de experimento para a geometria plana e a partir de 30 horas para a geometria cilíndrica. O coeficiente difusivo, obtido através da aplicação da Segunda Lei de Fick, para geometria plana foi de 6,4 x 10(-4)m2/s e para a geometria cilíndrica de 3,35 x 10(-4) m2/s.

The use of the nonlinear models in the growth of pears of 'Shinseiki' cultivar / O uso de modelos não lineares na descrição do crescimento de frutos de pereira cultivar 'Shinseiki'

ABSTRACT: The goal of this study was to elucidate the growth and development of the Asian pear fruit, on the grounds of length, diameter and fresh weight determined over time, using the non-linear Gompertz and Logistic models. The specifications of the models were assessed utilizing the R statistical software, via the least squares method and iterative Gauss-Newton process (DRAPER & SMITH, 2014). The residual standard deviation, adjusted coefficient of determination and the Akaike information criterion were used to compare the models. The residual correlations, observed in the data for length and diameter, were modeled using the second-order regression process to render the residuals independent. The logistic model was highly suitable in demonstrating the data, revealing the Asian pear fruit growth to be sigmoid in shape, showing remarkable development for three variables. It showed an average of up to 125 days for length and diameter and 140 days for fresh fruit weight, with values of 72mm length, 80mm diameter and 224g heavy fat.

RESUMO: Este trabalho teve por objetivo descrever o crescimento e desenvolvimento de frutos de pereira asiática, com base no comprimento, diâmetro e peso fresco obtidos ao longo do tempo, pelos modelos não lineares Gompertz e Logístico. Os parâmetros dos modelos foram estimados utilizando rotinas no software R, pelo método de mínimos quadrados e processo iterativo de Gauss-Newton (DRAPER & SMITH, 2014). Os modelos foram comparados utilizando o desvio padrão residual, coeficiente de determinação ajustado e o critério de informação de Akaike. A correlação residual presente nos dados de comprimento e diâmetro foi modelada por processo auto-regressivo de segunda ordem, tornando os resíduos independentes. O modelo Logístico mostrou-se mais adequado para descrever os dados, comprovando o caráter sigmoidal do crescimento da pera asiática com desenvolvimento acentuado das três variáveis, com até 125 dias para o comprimento e diâmetro e 140 dias para o peso fresco dos frutos, estabilizando-se, em média, com 72mm de comprimento, 80mm de diâmetro e 224g de peso fresco.

Derivation of Ecological Protective Concentration using the Probabilistic Ecological Risk Assessment applicable for Korean Water Environment: (I) Cadmium

Probabilistic ecological risk assessment (PERA) for deriving ecological protective concentration (EPC) was previously suggested in USA, Australia, New Zealand, Canada, and Netherland. This study suggested the EPC of cadmium (Cd) based on the PERA to be suitable to Korean aquatic ecosystem. First, we collected reliable ecotoxicity data from reliable data without restriction and reliable data with restrictions. Next, we sorted the ecotoxicity data based on the site-specific locations, exposure duration, and water hardness. To correct toxicity by the water hardness, EU's hardness corrected algorithm was used with slope factor 0.89 and a benchmark of water hardness 100. EPC was calculated according to statistical extrapolation method (SEM), statistical extrapolation methodAcute to chronic ratio (SEMACR), and assessment factor method (AFM). As a result, aquatic toxicity data of Cd were collected from 43 acute toxicity data (4 Actinopterygill, 29 Branchiopoda, 1 Polychaeta, 2 Bryozoa, 6 Chlorophyceae, 1 Chanophyceae) and 40 chronic toxicity data (2 Actinopterygill, 23 Branchiopoda, 9 Chlorophyceae, 6 Macrophytes). Because toxicity data of Cd belongs to 4 classes in taxonomical classification, acute and chronic EPC (11.07 microg/l and 0.034 microg/l, respectively) was calculated according to SEM technique. These values were included in the range of international EPCs. This study would be useful to establish the ecological standard for the protection of aquatic ecosystem in Korea.