Comparison of evapotranspiration methods for an arid citrus production zone in Northwest Mexico [comparación de métodos para estimar la evapotranspiración en una zona árida citrícola del Noroeste de Mexico]
Navejas-Jimenez J.,1 Instituto Nacional Of Investigaciones Forestales Agricolas Y Pecuarias Inifap |
Rueda-Puente E.O.,University of Sonora |
Avila-Serrano N.Y.,University of the Sea
Tropical and Subtropical Agroecosystems | Year: 2011
Water is essential to current and evolving ecosystem of plants and animals. It is a resource and a factor which interacts with the climatic and soil conditions, so its quantity in the atmosphere and soil has a direct impact on the ecosystems. Water is the essential part of protoplasm plant and is primordial for the photosynthesis process. The amount, frequency and distribution of precipitation are relevant because of its relationship with the stages of vegetative growth. In the arid zone of Baja California Sur, the average annual rainfall is 175 mm, unevenly distributed throughout the year and the temperature varies from 5 to 40 °C. Orange orchards face serious problems in adapting to the prevailing agro-climatic conditions, mainly to the evapotranspirative demand. The actual evapotranspiration (ETreal) is the process by which water is evaporated from the soil and transpired by plants. From the water use vewpoint, the estimation of ETreal is relevant for the application, frequency and quantity of applied irrigations. The estimates of ETreal allow to quantify the demand of the water resources and to determine the dimensions of the hydraulic irrigation-related works. The purpose of this study was to determine the water demand by means of methods to estimate the evapotranspiration of orange, in the arid citrus production zone of Baja California Sur, Mexico. For orange trees, water demand averaged 6.8 and 5.2 mm día-1, with indirect and direct ET methods, respectively; thus, a difference of 30.8% was observed between them. The standard deviations were 0.05 and 0.03, and the variation coefficients 7.35 and 5.77% in the same order. The net requirement of water per ha was 25 and 19 m3 per day, 175 and 134 m3 per week, and accordingly 751 and 574 m3 monthly, with indirect and direct ET methods, respectively. Those methods which consider climatological parameters, the soil characteristics and the response of plants are integrating models, being more representative of the agro-ecosystem. The use of water based on the application of methods which overestimate the ET implies a gradual deterioration and eventual depletion of the aquifer that sustains the production.