Estimation of the Evapotranspiration and Crop Coefficients of Bell Pepper Using a Removable Weighing Lysimeter: A Case Study in the Southeast of Spain

Abstract

Water use efficiency is essential in semiarid regions of Spain, and it can be achieved through a precise knowledge of the real crop water requirements (CWR). The Food and Agriculture Organization of the United Nations (FAO) offers standardized crop coefficients to establish the CWR. However, these coefficients can change due to different conditions, such as climatic variations and cultivation practices. In this work, the evapotranspiration (ETClys) and crop coefficients (KClys) of bell pepper were obtained with a compact removable weighing lysimeter between February and August for two crop seasons (2019 and 2020). ETClys was determined from the water balance, and the KClys values were determined as the ratio of the crop evapotranspiration, measured on the removable weighing lysimeter, and the reference evapotranspiration. The KClys average values for the bell pepper in the initial, middle, and final stages were 0.57, 1.06, and 0.80, respectively. KC regression models were obtained as a function of the fraction thermal units, achieving a maximum correlation of 0.67 (R2). In general, the KC values obtained in this research work were lower in the initial and in the final stages and larger in the middle stage in comparison with the FAO-56 values and other research works values in semiarid conditions. The bell pepper yield increased by 7.72% in 2019 and by 3.49% in 2020 compared to the yield reported by the Ministry of the Environment and Rural and Marine Areas of the Spanish Government in 2019 and with a minimum water loss through drainage. The results in this work can help farmers to determine the crop water requirements and to improve the system efficiency in semiarid locations with similar conditions to those in the study.

Estimating cucumber crop coefficients under different greenhouse microclimatic conditions

“…Hourly crop coefficients are needed to optimize the water application efficiency of high-frequency irrigation systems, even though they are rarely reported in the literature (Irmak et al 2013 ). Research over the past years has demonstrated that growth stage-specific K C values are also site-specific as they are sensitive to changes in air vapor density, air temperature, wind speed, and to a lesser degree to solar radiation (Annandale and Stockle 1994 ; Čerekovic et al 2010 ; Mulovhedzi et al 2020 ; Ávila-Dávila et al 2021 ). Particularly, the primary limitation in semi-arid regions for estimating greenhouse K C values is related to the energy and mass fluxes of the greenhouse atmosphere.…”

La evolución del riego inteligente

“…En este sentido, se enumeran las principales actuaciones que se han realizado: Se han analizado los cultivos objetivo de un lisímetro de pesada para establecer las dimensiones óptimas para hacerlo estándar (1); se han desarrollado ensayos en campo a fin de obtener un equipo de lisimetría robusto y fiable, cuya información sea útil para el agricultor, dando lugar a bastantes algoritmos (2,6,7); se ha trabajado con sensores de humedad de menor coste (8,9); se ha trabajado para incorporar información agroclimática pública para el empleo en las decisiones del manejo de riego (10).…”