Soil solarization mechanisms

Numerous and complex mechanisms are reported in literature for soil solarization effects, involving also the combination of several interrelated processes (Katan 1987 Stapleton and DeVay 1995 Stapleton 1997), but main effects of solarization treatments were found related essentially to the thermal action of solarization and the consequent chemical and biological changes occurring in the soil. 

Stapleton JJ, DeVay JE (1995) Soil solarization a natural mechanism of integrated pest management. In Reuveni R (ed) Novel approaches to integrated pest management. Lewis, Boca Raton, FL, USA, pp 309-322... 

Living things, plants and ices are able to keep the results of environment impact, an information of that kind is recorded, for examples, by trees in a view of year layers (or Greenland ices). This recorded knowledge keeps a various facts about climate changes mechanisms, about solar activity, soil conditions and, in particular, the level of this very region contamination. 

Solarization process increases soil temperatures up to levels lethal to many plant pathogens and pests and, therefore, direct thermal inactivation is the most important and normally expected mechanism. Some studies on the biochemical bases of sensitivity of organisms to high temperatures hypothesized that heat sensitivity is related to small differences in cell macromolecules, leading to a lethal increase of intra-molecular hydrogen, ionic, and disulfide bonds (Brock 1978). Sundarum (1986) suggested a reduced cell membrane function beyond an upper limit fluidity... 

Ion implantation is another common noble gas trapping mechanism in nature. For example lunar soils are implanted by solar emission particles that essentially consist of lighter noble gases. A few laboratory experiments have been carried out with the hope that experiments may be relevant to incorporation of noble gases in early solar... 

After volatilization, biodegradation and photooxidation are the most important removal mechanisms for gasoline hydrocarbons released to surface soils (Air Force 1989). Photooxidation in surface soils is less important than in surface water environments since infiltration of the liquid product into the soil will limit exposure to solar radiation (Bossert and Bartha 1984). 

Other encapsulation applications of polymers for specific designs Include soil, ultraviolet, and abrasion-resistant front covers. The cover can serve as a transparent structural superstrata. Substrate support designs require a hard, durable front cover film to protect the relatively soft pottant from mechanical damages and excess soil accumulation. A polymeric front cover must be low In cost, highly transparent, and weather resistant to compete with glass. For applications out of the optical path between the sun and the solar cells (adhesives. Insulation, edge seals, gaskets) requirements for polymeric use In encapsulation are the same as for other applications. 

Fiber-reinforced polyesters - Their properties depend on the composition of the resin and the amount and distribution of the fibers. The composite composition determines the penetration of light as well as its mechanical and chemical properties. Thus, the use of tetrachlorophthalic acid increases the refractive index whereas the use of PMMA in place of styrene lowers the diffusion power and increases the transparency and stability of the product. Polyesters are slightly transparent to UV radiation and the penetration is further reduced or eliminated by UV absorbers. Transparency of reinforced polyesters to solar radiation is low and hence gives rise to a reduced temperature build-up. The greenhouse effect results from the opacity of this material to radiation emitted by the soil. 

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