Actual evapotranspiration and crop coefficient of sweet orange during the initial development phase in the Rio Largo region, Alagoas

Abstract

Determining actual crop evapotranspiration (ETa) is paramount for irrigation management. The principal measurement methods and physical models generally require crop and weather data that are not readily available. We determined the crop coefficient (Kc) of sweet oranges during the initial development stage and evaluated the performance of the Poulovassilis semi-empirical model coupled with a simple soil water balance for estimating the ETa. The ETa was inferred from the variation in the soil water content over time, measured by time-domain reflectometry. In the Poulovassilis model, the ETa is obtained by multiplying the crop evapotranspiration (ETc) by an adjustment coefficient (ca), which accounts for a reduction in the evapotranspiration caused by soil water depletion. Soil water storage was obtained using the daily and 10-day soil water balances, computed by considering inputs and outputs of water from the system. The empirical parameter, ca, was determined using inverse modeling. The optimal ca value obtained through inverse modeling was 0.05 and 0.03 for the daily and 10-day soil water balances, respectively. The model performed better for the daily soil water balance than the 10-day balance, with performance comparable with the other ETa models. Average Kc during the sweet orange initial crop stage was 0.85.

Effect of irrigation regime and spraying salicylic acid on characteristics and quality of (Banzahir) lime fruits (Citrus aurantifolia B.) at harvest, marketing and some water relations.

“…Therefore, the seasonal irrigation applied water is higher under 100% followed by 80% and 60% ETc for lime trees during the two growth years. These results are in the same line with those reported by Zaghloul (2017), Silva et al (2019) and Jamshidi et al (2020).…”

“…The maximum crop evapotranspiration was in June this is due to increase the reference evapotranspiration during this month compared to the other months in the year. These results are in the same line with those reported by Al-Naeem (2014), Zaghloul and Moursi (2017), Silva et al (2019) and Jamshidi et al (2020).…”