Estrutura térmica de solos do Nordeste do Brasil.

Abstract

The thermal behavior of different soil types in the nprthest of Brazil was studied by means of the harmonic analysis technique. The soil temperature data were collected at three climatological stations (Campina Grande - PB, São Gonçalo - PB and Surubim - PE) and two agricultural meteorological stations (Bebedouro - PE and Mandacaru - BA). The temperature data were obtained at 1200, 1800 and 2400 GMT for the depths of 02, 05, 10, 20, 30, 50 and 100cm. Using this data the thermal properties such as the annual amplitude an fase of the first five harmonics of the Fourier series, the damping depth and the elocity of propagation of the temperature wave were determined. The thermal diffusivity values for different players were calculated using the amplitude and fase information of the annual cycle for all the five stations mentioned above. The thermal behavior of the soil under corn crop subjected two different hydrostatic pressures was also studied and compared with that of an adjacent bare soil location. For this part of the study the daily soil temperature data were obtained at three different depths (15, 30 an 60 cm) by means of distant thermographs. The values of thermal diffusivity, damping depth, velocity of propagation, etc... obtained for different soil in the northest of Brazil are in reasonable agreement with those found in the literature.