Consumo hídrico y transpiración de juveniles de Persea americana y Pinus pseudostrobus

Abstract

Mexico is the world's top avocado producer. In Michoacan (central Mexico), roughly 150,000 hectares of this crop are dedicated to it. However, a considerable amount of this surface was established, replacing native forests; the hydrological impact of this land use change is unknown. In this contribution we addressed the following question; How much water does avocado tree saplings use and how does it compare to a native forest tree species saplings?. To answer this question, we conducted a field experiment with ten Pinus pseudostrobus and Persea americana var saplings. Hass saplings. Gravimetric water loss measurements were performed to quantify water consumption and plant transpiration in 12:00 hour intervals for 95-day periods, comprising both the dry and wet seasons (2017); we also measured plant leaf area. Results indicate that avocado saplings transpired  0.90 ± 0.69 mm day-1, while pines transpired 0.45 ± 0.51 mm day-1, corresponding to 0.92 L day-1 of water consumption per m² of leaf area in avocados and 0.28 L day-1 in pines. During the dry season, avocado saplings used up to 6.6 times more water per m² of leaf area than pines and 1.85 times more during the wet season. The best-explaining variables for water use and transpiration in both tested species were mean daily temperature, vapor pressure deficit, wind speed, and relative humidity. Upscaling at the stand/orchard level for a forest site and three avocado orchards are discussed.