Performance of methods for estimation of table beet water requirement in Alagoas

Abstract

Optimization of water use in agriculture is fundamental, particularly in regions where water scarcity is intense, requiring the adoption of technologies that promote increased irrigation efficiency. The objective of this study was to evaluate evapotranspiration models and to estimate the crop coefficients of beet grown in a drainage lysimeter in the Agreste region of Alagoas. The experiment was conducted at the Campus of the Federal University of Alagoas - UFAL, in the municipality of Arapiraca, AL, between March and April 2014. Crop evapotranspiration (ETc) was estimated in drainage lysimeters and reference evapotranspiration (ETo) by Penman-Monteith-FAO 56 and Hargreaves-Samani methods. The Hargreaves-Samani method presented a good performance index for ETo estimation compared with the Penman-Monteith-FAO method, indicating that it is adequate for the study area. Beet ETc showed a cumulative demand of 202.11 mm for a cumulative reference evapotranspiration of 152.00 mm. Kc values determined using the Penman-Monteith-FAO 56 and Hargreaves-Samani methods were overestimated, in comparison to the Kc values of the FAO-56 standard method. With the obtained results, it is possible to correct the equations of the methods for the region, allowing for adequate irrigation management.

Accuracy of Potential Evapotranspiration Models in Different Time Scales

“…Há métodos empíricos da ETP com entrada mínima de dados, a exemplo Thornthwaite (1948) e Camargo (1971) que são utilizados com mais frequência e requerem apenas a temperatura do ar (Santos et al, 2018;Gharbia et al, 2018;Ma et al, 2018;Moraes et al, 2018;Seong et al, 2018). Enquanto, Jensen-Haise (1963) e Makkink (1957) são baseados na radiação solar, os quais requerem apenas os dados de temperatura máxima e mínima do ar.…”

Fruit characteristics of cantaloupe melon in protected environment subjected to irrigation frequencies and substrate volumes

“…The determination of the volume of water applied in irrigation was performed using evaporation data from a class A pan installed inside the agricultural greenhouse. From the pan evaporation values, adopting a pan coefficient (Kp) of 0.85 and melon crop coefficients of 0.50, 0.80, 1.05 and 0.75, corresponding to the initial, vegetative, fruiting and ripening periods, respectively, the irrigation rates were calculated (Santos et al, 2018).…”