Abstract

PANTOJO DE SOUZA, Débora et al. Crop coefficient estimated by degree-days for ‘Marandu’ palisadegrass and mixed forage. Rev. Fac. Cienc. Agrar., Univ. Nac. Cuyo [online]. 2021, vol.53, n.2, pp.71-81. ISSN 1853-8665.

Considering profitability in pasture-based systems, investigating parameters affecting crop coefficients for irrigation management becomes important. In this experiment, we determined the crop coefficient of ‘Marandu’ palisadegrass based on accumulated degree-days and estimated plant water consumption under single (‘Marandu’ palisade grass) and mixed (‘Marandu’ palisadegrass + black oats + Italian ryegrass) cropping regimes. The research was conducted at the Luiz de Queiroz College of Agriculture in Piracicaba, São Paulo, Brazil, between 2016 and 2017. Evapotranspiration was assessed using weighing lysimeters while crop evapotranspiration was calculated using mean weight variation. Reference evapotranspiration and degree-days were estimated. Data were obtained from an automated weather station. Equations and regression models relating crop coefficient with accumulated degree-days were generated for two seasons (spring/summer and autumn/ winter) and evaluated for two year-cycles, from 2015 to 2018. The results showed better prediction accuracy for the single cropping system in spring/summer 2017-18.

Keywords : Degree-days; Evapotranspiration; Water consumption; Forage.

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