POTENTIAL EVAPOTRANSPIRATION OF PEACH PALMS UNDER SOUTHEASTERN BRAZIL CONDITIONS

Abstract

The Amazonian peach palm (Bactris gasipaes Kunth), has been cultivated in southeastern Brazil for heart-of-palm production. Internationally known as a gourmet vegetable, the peach palm heart-of-palm market is expanding in Brazil. Due to its recent introduction in the southeastern Brazilian region, there are so far few studies on water consumption of the species. Being from an Amazonian habitat under a high rainfall throughout the year, the peach palm demands a suitable condition of soil water to yield economically. However, the Brazilian southeastern region, the main market for heart-of-palm in Brazil, shows seasonal soil water deficit, and thus, peach palms must be grown under irrigation. Aiming to quantify the water consumptive use of a peach palm commercial crop, to support an appropriate irrigation management, this experiment was designed to estimate the peach palms transpiration rate through sap flow measurements using the heat dissipation probe method. Sensors were installed in twelve peach palms divided into four classes, according to the main stem height and diameter, with three replications per class, to represent a standard peach palm clump of a commercial crop. Measurements have been carried out in nine year-old peach palms spaced 2 x 1 m, under irrigation, to evaluate the potential evapotranspiration. The calibration equation used was obtained in the laboratory by using a hydraulic system to simulate the sap flow. Partial results indicate the proper functioning of the sensors under field conditions, showing reliability and consistency of values, when compared to the air evaporative demand. Further measurements have been performed such as the leaf area, which has been measured in the peach palms from this experiment and in other ten peach palms. The latter were used to evaluate the relative transpiration, as well as to extrapolate the results for the entire population.