Soil solarization process

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. 

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... 

Function of a plastic film in the solarizing process is to increase soil temperature by allowing passage of solar radiation while reducing energetic radiative and... 

If soilborne pests ore a big problem in your garden, why waste your energy trying to combat them Let the sun do it for you This process, known as soil solarization, involves covering the soil with clear plastic, so the heat can build up and destroy the soil organisms and weed seeds. Keep in mind that the high temperatures can also harm beneficial insects and organisms that live in the soil only use this process when you have a serious pest or disease problem. 

Soil solarization, or heating soil with solar radiation, involves covering the soils with clean polyethylene sheets during summer or months with bright sunshine and clear skies. The process raises the soil heat and temperature, killing soil-bome pathogens and pests that lower the yield of most of the field crops. This... 

The time of year in which a pesticide is applied significantly affects its dissipation rate due to temperature, moisture, and solar-irradiance effects on abiotic and biotic dissipation processes. For example, dissipation rates for agrochemical applications made in the springtime are normally greater than those observed for fall (autumn) applications. Thus, the timing of agrochemical applications made in field soil dissipation studies should closely match those occurring under acmal-use conditions. 

The discovery of homochirality on a planet such as Mars could be an excellent biomarker and strengthen the argument for life on Mars. With an EE in the solar nebula there should be an EE on the surface of Mars of order 9 per cent but remains of ancient life on Mars would show a greater excess. The interchange of enantiomers occurs naturally in a process called racemisation and for the most labile amino acid, aspartic acid, the half-life for the racemisation is 800 years at 300 K in 800 years, half of the non-biotic aspartic acid would racemise and the EE would go to zero. In dry conditions, however, the half-life is much longer, perhaps as large as 5 x 104 years at 300 K. Extrapolation of the racemisation rate to 215 K, the equatorial temperature of Mars, extends the half-life further to 3 x 1012 years and to 1027 years at 150 K, Martian polar temperatures. Hence, discovery of a considerable EE in the Martian soil would be a strong indicator of ancient Martian life. 

Rubin B, Benjamin J (1984) Solar heating of the soil involvement of environmental factors in the weed control process. Weed Sci 32 138-142... 

Phytoremediation is only effective at shallow depths because root density decreases with depth. The mobility of contaminants also decreases with depth. In addition, phytoremediation is a slower process than some alternative technologies, and cleanup often requires several growing seasons. Environmental factors, including soil type, water availability, temperature, nutrients, and solar radiation can also limit the success of phytoremediation. 

However, this is not the case for airborne particles composed of crustal materials formed by erosion processes. As discussed in Chapter 9.C, mineral dust consists primarily of such crustal materials. Despite the fact that soil dust particles tend to be quite large, of the order of a micron and larger, they can be carried large distances. These particles not only scatter and absorb solar radiation but also absorb long-wavelength infrared emitted by the earth s surface. 

For most of the chemical elements, the relative abundances of their stable isotopes in the Sun and solar nebula are well known, so that any departures from those values that may be found in meteorites and planetary materials can then be interpreted in terms of planet-forming processes. This is best illustrated for the noble gases neon, argon, krypton, and xenon. The solar isotopic abundances are known through laboratory mass-spectrometric analysis of solar wind extracted from lunar soils (Eberhardt et al., 1970) and gas-rich meteorites. Noble gases in other meteorites and in the atmospheres of Earth and Mars show many substantial differences from the solar composition, due to a variety of nonsolar processes, e.g., excesses of " Ar and... 

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