A solarization site was established on the grounds of the Sawtooth Community Garden south of Ketchum, Idaho, in 1995. Feasibility of solarization for weed control was determined in a region of sunny, warm days and cool nights. Elevation of the site was 1829 m, with a growing season of 90 days. Treatments of double and single layers of clear and IRT plastic were applied 23 May 1995. These solarization treatments were compared to hand-hoeing, glyphosate sprays, and no control. Highest soil temperatures were reached under the double clear plastic, where daily peak temperatures ranged from 19 to 46C. Plastic treatments were removed on 30 Aug. 1995. Weed growth and growth of peas, green beans, carrots, and beets were recorded during the summer of 1996. Weed growth on 14 June 1996 ranged from 0.3 to 0.8 weeds/m2 in the solarization, hand-hoe, and glyphosate treatments and was 22.4 weeds/m2 in the no control treatment. On 20 Aug., weeds/m2 ranged from 1.4 to 2.0 in the solarization, hand-hoe, and glyphosate treatments and was 20.4 weeds/m2 in the no control treatment. At both dates there was no significant differences between weed control treatments, and any weed control method was significantly better than no control. Weight per plant of beets and beans was no different across all treatments. Carrot and pea plants were smaller in the no control treatments, and some variable differences were noted between weed control treatments. Results indicate that solarization in short-season, cool climates will result in little to no advantage over hand-hoeing or herbicide control of weeds, and no subsequent differences in crop growth can be expected.
If the inline PDF is not rendering correctly, you can download the PDF file here.