Calibração de sonda de dissipação térmica e estimativa da transpiração do cacaueiro cultivado a pleno sol

The objective of study was evaluating heat dissipation probe (SDT) method in the estimate of transpiration of cacao tree plantation under full sunlight. The study consisted of two experiments. . The first experiment was carried out experimental camp belonging to the Engineering Center of Water and Soil - NEAS, Federal University of Bahia in the Reconcavo, located in the municipality from Cruz das Almas – BA, (12° 48` S; 39° 06` W; 225 m by altitude). The study was conducted with seminal cacao tree plants, in development early phase and it were transplanted in pots 60 liters and 500 liters. It was determined sap flow by SDT method, With probes of length 1 cm considering the effective sectional area of the xylem driving the crude sap. Natural differences by temperature measurement in the stem were correlated with two probes taken as reference. With the results can be to observe SDT method with the linear coefficient of the modified equation F=0,000135K1,231AS proved effective in estimate sap flow. The second experiment was carried by in the Nova Conquista farm, in Nova Redenção municipality - Bahia (S 12° 51`46`` e W 41° 08`14``). It were selected six plants (seminal plant 4 and CCN51 clone 2), in orchard of cocoa tree mature plants plantation under full sunlight. The percentage of available soil water was calculated from the ratio of water availability in the soil for total available water in the soil. With the results obtained, it was found an increase in the sap flow with the replacement of water in the soil. The results obtained with thermal dissipation sensors possible estimating cacao transpiration in the experiment conditions.