Determination of Evapotranspiration and Crop Coefficient for Tomato by Using Non-Weighing Lysimeter in Semiarid Region

Abstract

Providing an accurate amount of water to crops based on their requirements is the primary objective of irrigated agriculture. The crop evapotranspiration and coefficient of tomato were measured using non-weighing lysimeters. The trial was conducted at the Melkassa Agricultural Research Center’s experimental farmland in Ethiopia. The soil water balance approach was applied to compute tomato crop evapotranspiration, whereas the reference evapotranspiration was computed using the Penman-Monteith method. The crop coefficient was calculated using the ratio between the measured crop evapotranspiration and the reference evapotranspiration. A total of 590.4 and 413.3 mm of tomato seasonal evapotranspiration was recorded in the experimental years 2022 and 2023, respectively. The mean crop evapotranspiration for tomatoes over the two experimental years was 501.83 mm. The mean locally produced crop coefficient values were 0.63 for the initial, 1.18 during the mid, and 0.94 at the end of the season. The FAO-adjusted Kc values were 1.12 during the mid and 0.86 at the end of the season. The FAO-adjusted crop coefficient values differed from the crop coefficient values developed. Hence, to ensure efficient irrigation scheduling and planning, measuring the crop evapotranspiration and coefficient for optimal crop production under specific climatic conditions is vital.