SOIL HEATING BY SOLARIZATION INSIDE PLASTIC GREENHOUSE IN SANTA-MARIA, RIO-GRANDE-DO-SUL, BRAZIL

Solar heating of soil by mulching with transparent polyethylene (known as soil solarization) is a physical method of soil disinfestation. Th e increase in soil temperature by solarization inside a plastic greenh ouse in Santa Maria, Rio Grande do Sul State, Brazil, was measured. II was estimated the time which soil temperature exceeded some thermal l evels in solarized soil, During the 1992/93 and 1993/94 summers, exper iments were carried out in a 10 m x 25 m plastic greenhouse. Soil temp erature was measured at 2 cm, 5 cm, 10 cm, and 20 cm depths in one sol arized and uncovered plot. An increase of 10 degrees C or more was obs erved in solarized soil at 2 cm and 5 cm depths in comparison to the b are soil. Soil temperature exceeded 50 degrees C or more several days during 1993/94 up to the 10 cm depth. The estimated exposure time al s everal thermal levels in solarized soil allow to conclude that solariz ation presents potential in the region.