SUMMARY Temperature modification in soil of plastic greenhouse caused by solarization in the Subtropical Central Region of the Rio Grande do Sul state, Brazil, was measured during the summer. The experiment was carried out in a 10m x 25m greenhouse covered with low density transparent polyethylene (PE). Four 6m x 4m plots were mulched with 100pm thickness PE sheets, from 12/17/92 to 03/07/93. Additional four plots (same size) without covering were used as controls (bare soil). The results showed that solarization raised maximum temperature, on the average, 11.9°C, 10.8°C, 9.8°C, and 8.6°C over uncovered control soil at 2, 5, 10. and 20cm depth, respectively. It was also observed that soil temperature achieved absolute values of up to 54.4°C at 2cm snf 50.2°C at 5cm depth. Temperatures exceeding 45°C and 50°C in solarized soil have also occured in several days.
solarization; soil temperature; plastic greenhouse