Soil Solarization consists of covering the soil with a clear, polyethylene tarp for 4-6 weeks during a hot period. This method controls a wide range of soil- borne fungi, weed seeds, and nematodes in fields. Soil that has been solarized allows plants to draw on the nutrients, especially nitrogen, calcium, and magnesium more readily. In solarized soils, crop seeds germinate quickly and grow faster, with substantial increased yields.
Solarization acts similarly to a greenhouse, where a transparent film covering the soil, e.g. 3- 6 mm plastic sheeting, traps the sun's heat. After several days of sunshine, soil temperatures rise to as high as 140 degrees at the surface and well offer 100 degrees as far down as 20 cm. These temperatures are normally reached after four- six weeks of solarization.
Soil must be well prepared by tilling. Deep cultivation followed by harrowing and rolling helps to achieve the desired preparation. The field must be irrigated at field capacity before mulching. Before mulching an additional rolling may be necessary.
Small plots can be covered manually and films should be laid tightly over soil surface not leaving any place for air, otherwise weeds may emerge easily in these spots. There is machine available to lay the films in large areas to be solarized. Once the film is laid it is necessary to wait a month or a month and a half for getting the complete effect of solarization.
For more information on this method and its effectiveness consult:
Soil solarization, FAO 1991, Proceedings of the First International Conference on Soil Solarization, Amman, Jordan, 19-25 February 1990. Edited by James E. DeVay, Plant Pathology Dept, University of California, Davis, CA. James J. Stapleton Statewide Integrated Pest Management Project, University of California, Modesto, CA. Clyde L. Elmore, Botany Dept, University of California, Davis, CA [more]
Soil solarization. By Barakat Abu Irmaileh [more]