| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.5 MB | Adobe PDF |
Advisor(s)
Abstract(s)
Descreve-se a determinação das necessidades hídricas da cultura do pessegueiro utilizando um método de medição directa da evapotranspiração. Estes ensaios decorreram na região da Península de Setúbal durante a década de 1990, em cinco épocas de rega e em dois pomares de diferentes variedades e com distintos sistemas de rega e modos de condução, conferindo-lhes uma variabilidade espacial e temporal de aplicação da água.
Para medir a evapotranspiração recorreu-se ao método das flutuações instantâneas. Utilizou-se ainda um conjunto alargado de técnicas adicionais, permitindo a quantificação da transpiração das plantas e da evaporação directa do solo, e a consequente extensão dos valores de evapotranspiração temporalmente ou espacialmente, e a avaliação do estado hídrico das plantas. Os resultados mostraram-se similares com gamas de variação e valores médios de evapotranspiração e transpiração, para os períodos amostrados, sendo, no entanto, distintos no que diz respeito à evaporação directa do solo, se bem que esta componente dos fluxos evaporativos tivesse reduzida relativa expressão. A avaliação conjunta de diversas variáveis relacionadas com o estado hídrico das plantas mostrou um comportamento similar para as duas variedades quando se relacionou a condutância estomática com o potencial hídrico, mas diferenciado quando se observou simultaneamente a progressão do défice hídrico com a evolução de transpiração.
Apresenta-se uma breve descrição das técnicas utilizadas nos dois ensaios experimentais, bem como uma súmula e diversos exemplos dos resultados mais representativos. Comparam-se os resultados obtidos em ambas as situações e indicam-se semelhanças, passíveis de generalização para o tipo de pomar observado, e diferenças, explorando-se as suas razões.
Os dados obtidos permitiram contribuir para a melhoria da estimativa da evapotranspiração em pomar de pessegueiro, quando se recorre a modelos baseados em coeficientes culturais, para aplicações práticas no domínio da rega.
The determination of the water requirements of peach orchards is described, using a direct method for measuring evapotranspiration. These trials took place in the Setúbal Peninsula region during the 1990s, over five irrigation seasons, in two orchards with different varieties, irrigation systems and scheduling, providing spatial and temporal variability in water application. The measurement of evapotranspiration was carried out using the eddy covariance method. Additionally, a wide range of supplementary techniques was employed, enabling the quantification of plant transpiration and direct evaporation from the soil, the extrapolation of evapotranspiration values over extended periods, and the assessment of plant water status. The results showed similar ranges and mean values for evapotranspiration and transpiration during the sampled periods. However, differences were observed in the process of direct soil evaporation, though this component of evaporative fluxes had relatively low expression. The combined evaluation of various variables related to plant water status revealed similar behavior between the two varieties in terms of the relationship between stomatal conductance and water potential. However, differences emerged when simultaneously analyzing the progression of water deficit and the evolution of transpiration. A brief description of the techniques used in the two experimental trials is provided, along with a summary and various examples of the most representative results. A comparison of the results from both scenarios highlights similarities, which can be generalized for the observed type of orchard, and differences, which are explored for their underlying causes. The data obtained contributed to improving the estimation of evapotranspiration in peach orchards when using models based on crop coefficients, for practical irrigation applications.
The determination of the water requirements of peach orchards is described, using a direct method for measuring evapotranspiration. These trials took place in the Setúbal Peninsula region during the 1990s, over five irrigation seasons, in two orchards with different varieties, irrigation systems and scheduling, providing spatial and temporal variability in water application. The measurement of evapotranspiration was carried out using the eddy covariance method. Additionally, a wide range of supplementary techniques was employed, enabling the quantification of plant transpiration and direct evaporation from the soil, the extrapolation of evapotranspiration values over extended periods, and the assessment of plant water status. The results showed similar ranges and mean values for evapotranspiration and transpiration during the sampled periods. However, differences were observed in the process of direct soil evaporation, though this component of evaporative fluxes had relatively low expression. The combined evaluation of various variables related to plant water status revealed similar behavior between the two varieties in terms of the relationship between stomatal conductance and water potential. However, differences emerged when simultaneously analyzing the progression of water deficit and the evolution of transpiration. A brief description of the techniques used in the two experimental trials is provided, along with a summary and various examples of the most representative results. A comparison of the results from both scenarios highlights similarities, which can be generalized for the observed type of orchard, and differences, which are explored for their underlying causes. The data obtained contributed to improving the estimation of evapotranspiration in peach orchards when using models based on crop coefficients, for practical irrigation applications.
Description
Keywords
necessidades hídricas rega Prunus persica flutuações instantâneas fluxo de seiva water requirements irrigation Prunus persica eddy covariance sap flow
Pedagogical Context
Citation
Paço T. A., Ferreira, M.I., Conceição, N. (2024) Medições de referência de evapotranspiração, transpiração e evaporação direta do solo em pomar de pessegueiro, em Portugal. Anais do Instituto Superior de Agronomia. Vol. 50, p. 161-183