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Title: EFFECTS OF SOIL TEMPERATURE AND TUBER DEPTH ON NUTSEDGE (CYPERUS SPP.) CONTROL BY SOIL SOLARIZATION

Author
item Chase, Carlene

Submitted to: Weed Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: USDA, ARS scientists at Gainesville, FL have been investigating the possibility of sanitizing soil by soil heating resulting from the installation of clear, heat-conserving plastics on planting beds several weeks prior to the planting of the crop. This management scheme, commonly referred to as soil solarization, can control weeds by killing their propagules directly and by foliar scorching of weeds that emerge under the film. In laboratory experiments it was determined that the lethal temperature for nutsedge tubers was greater than 45 degrees C. In field studies temperatures exceeding 45 degrees C were found only in the top 10 cm of solarized soil. Improved solarization films were more effective at controlling purple nutsedge, primarily because they promoted higher soil temperatures than conventional low density plastic film.

Technical Abstract: The effect of oscillations in soil temperature with maxima of 40, 45, 50, 55c on nutsedge tuber mortality was evaluated. Sprouting of tubers and growth of nutsedge plants were faster at 40c than with a control treatment held at room temperature (26c). With purple nutsedge this resulted in a higher number of shoots at the end of a 2-wk incubation. The 45c treatment delayed emergence but was not lethal to nutsedge tubers. Purple and yellow nutsedge tuber mortality was 100% with the 50 and 55c treatments. In a field study, thermal-infrared-retentive (TIR) films resulted in higher soil temperatures than a 30 m low density polyethylene (LDPE) clear film at all soil depths. After 6 weeks of soil solarization, TIR films were more effective than the LDPE film in reducing purple nutsedge density. Four weeks after film removal, the lowest level of control was obtained with the 30 m LDPE film. For the 5 and 10 cm planting depths, the level of control with the LDPE film was 62%, which decreased by half when the planting depth was increased to 15 cm. The best control, 4 weeks after film removal, was obtained with the 75 m and 100 m TIR; 95% and 92%, respectively. There was no significant effect of planting depth with the TIR films.