Calibração de sonda tdr, implicações na variação do conteúdo de água no solo em cacaueiro irrigado

Abstract

The cocoa tree (Theobroma cacao L.) is a plant native to South and Central America, and its almonds have great added value for the food industry in the world. Its traditional cultivation is carried out in cabruca, where part of the native forest is thinned and the culture is implanted, protected by the shade of large trees. With the need for cocoa expansion, its cultivation is currently being implemented in semi-arid regions, where cultivation is always done with the aid of irrigation, as the crop has a high water demand. In this context, an experiment was carried out with the cocoa tree subjected to two forms of cultivation, in single sun plan and intercropped with banana and paricá. The two conditions were irrigated with the three-day irrigation shift and daily soil moisture data were collected in the field with the aid of TDR probes. These probes were inserted close to the plants and, with the TDR100 reader, it was possible to obtain the Ka values and then estimate the volumetric water content values in the soil. The estimation equation was the result of the calibration of the TDR probes in the soil collected in the field at three depths (0-15; 15-30 and 30-45 cm), which later gave rise to three cubic polynomial equations. At the end of the one month period of the experiment, the daily data collected were transformed into millimeters of soil storage for the different conditions. It can be concluded that the best soil storage in mm was the shade condition, this is due to the lower presence of solar radiation and the presence of litter, both providing greater durability of moisture in the soil.