VIEW ARTICLE

Techniques

Temperature Evaluation in Solarized Soils by Fourier Analysis. J. L. Cenis, Nematologist, Dpto. Protección Vegetal, Centro Regional de Investigaciones Agrarias, La Alberca, Murcia, Spain, Present address: Dpto. Protección Vegetal, C.I.T.-I.N.I.A., Apdo. 8111, 28080 Madrid, Spain; Phytopathology 79:506-510. Accepted for publication 25 July 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/Phyto-79-506.

Fourier analysis, a methodology for the mathematical treatment of periodic phenomena, was used to describe temperature variations in a solarized soil. Starting from the daily maximum and minimum temperatures at two depths in a homogeneous soil, a daily sinusoidal equation can be applied that gives the soil temperature at any hour and depth. The validity of the method was studied during a three-summer temperature-recording period. The fitted sinusoidal equations accounted for at least 93% of the variation, and the hourly mean differences between the measured soil temperatures and those derived from the equations calculated for the solarization period did not surpass 1.9 C. Soil temperature throughout the solarization period was estimated by using the data of 7 days as a sample. A sinusoidal equation from the data of the first week of solarization was calculated and used as a representative of the whole solarization period. The hourly mean differences between measured and estimated temperatures for the three solarization periods were 2.2 C at 10 cm, 1.3 C at 20 cm, and 1.4 C at 30 cm.