The method involves heating the soil by covering it with a clear plastic tarp for 4 to 6 weeks during a hot period of the year when the soil will receive the most direct sunlight. When properly done, the top 6 inches of the soil will heat up to as high as 140°F, depending on the location. The plastic sheets allow the sun's radiant energy to be trapped in the soil, heating the upper levels.
Solarization during the hot summer months can increase soil temperature to levels that kill many disease-causing organisms (pathogens), nematodes, and weed seed and seedlings.
Direct thermal inactivation of target organisms was found to be the most important mechanism of solarization biocidal effect, contributed also by a heat-induced release of toxic volatile compounds and a shift of soil microflora to microorganisms antagonist of plant pathogens.
Solarization leaves no chemical residues and is a simple method appropriate for the home gardener or the large-scale farmer. The process changes physical, chemical, and biological properties and thereby improves soil health.
Solar heating was normally reported to improve soil structure and increase soil content of soluble nutrients, particularly dissolved organic matter, inorganic nitrogen forms, and available cations, and shift composition and richness of soil microbial communities, with a marked increase of plant growth beneficial, plant pathogen antagonistic or root quick recolonizer microorganisms.
Soil solarization is a simple, safe, and effective alternative to toxic, costly soil fumigants and to the lengthy crop rotations needed to control many damaging soilborne pathogens and pests.
Soil solarization
