02205naa a2200229 a 450000100080000000500110000800800410001902200140006002400380007410000250011224501120013726000090024952015290025865000090178765000090179670000200180570000200182570000240184570000170186970000220188677300670190820960132018-09-21       2018    bl uuuu     u00u1 u    #d  a1806-96577 a10.1590/18069657rbcs201702212DOI1 aFARIAS, P. dos S. de  aHourly, daily, and monthly soil temperature fluctuations in a drought tolerant crop.h[electronic resource]  c2018  aSoil temperature is a physical property of great agricultural importance in the soil-plant relationship and in energy exchange with the atmosphere. This study was conducted in a degraded Cambissolo Háplico Ta Eutrófico (Cambisol; Inceptisol) in the Irecê Identity Territory, Bahia, Brazil, aiming to evaluate the hourly, daily, and monthly fluctuations of soil temperature at depth, and soil thermal diffusivity in the castor bean crop. Hourly soil temperature data from February 4, 2014, to September 30, 2015, were obtained by using thermocouple sensors (copper-constantan) horizontally installed at 0.05, 0.10, and 0.20 m depths. Soil thermal diffusivity was estimated by phase and amplitude methods. Results showed that, for most days, the soil temperature was at the level recommended for castor bean. The maximum and minimum hourly and daily soil temperatures were observed in October and July, respectively, and the maximum soil temperature values occurred at 4 p.m. (0.05 m), 5 p.m. (0.10 m), and 7 p.m. (0.20 m). Soil temperature variability is low, requiring few measurement points to estimate this factor in an area. The amplitude method led to soil thermal diffusivity values compatible with results in the literature. The absence of a relationship between thermal diffusivity and soil moisture was attributed to the clay-loam soil texture, predominance of micropores, and iron oxides allowing greater approximation to the soil particles, with high thermal diffusivity even under low soil moisture conditions.  aSoil  aSolo1 aSOUZA, L. da S.1 aPAIVA, A. DE Q.1 aOLIVEIRA, Á. S. de1 aSOUZA, L. D.1 aLEDO, C. A. da S.  tRevista Brasileira de Ciência do Sologv. 42, e0170221, 2018.