Soil solarization chemical

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. 

Chen Y, Gamliel A, Stapleton JJ, Aviad T (1991) Chemical, physical, and microbial changes related to plant growth in disinfested soils. In Katan J, DeVay JE (eds) Soil Solarization. CRC, Boca Raton, FL, USA, pp 103-129... 

Mauromicale G, Restuccia G, Marchese M (2001) Soil solarization, a non-chemical technique for controlling Orobanche crenata and improving yield of faba bean. Agronomie 21 757-765. doi 10.105 l/agro 2001167... 

Ricci MS, De Almeida DL, Ribeiro RD, Aquino AM, Pereira JC, Polli D, Reis VM, Eklund CR (2000) Cyperus rotundus control by solarization. Biol Agric Hort 17 151-157 Rieger M, Krewer G, Lewis P (2001) Solarization and chemical alternatives to methyl bromide for preplant soil treatment of strawberries. HortTechnology 11 258-264 Ristaino JB, Perry KB, Lumsden RD (1991) Effect of soil solarization and Gliocladium virens on sclerotia of Sclerotium rolfsii, soil microbiota, and the incidence of southern blight in tomato. Phytopathology 81 1117-1124... 

Besides structural, compositional, morphological, and dimensional (especially thickness) sample characteristics, behavior during natural aging also depends on geographic location (latitude, altitude, mountain, sea, desert, etc.), solar radiation intensity, season, (thermal cycling), environment (indoor or outdoor hot, cold, or seawater soil type, chemicals), rain, humidity, atmospheric contamination (pollutants, smoke, fog), etc. 

Chellemi DO, Rhoads FM, Olson SM, Rich JR, Murray D, Murray G, Sylvia DM (1999) An alternative, low-input production system for fresh market tomatoes. Am J Altem Agric 14 59-68 Chen Y, Katan J (1980) Effect of solar heating of soils by transparent poliethilene mulching on their chemical properties. Soil Sci 130 271-277... 

Solarization offers one of the few non-chemical possibilities for reducing some soil insects, nematodes, diseases and weed seed simultaneously. This procedure requires bare, moist soil and the hottest possible temperatures. The best conditions for solarization are periods of bright, sunny weather, which generally occur during the long, warm days of summer. Begin the procedure in June or early July. 

Other factors do intervene. Significant solar heating of the soil surface, so that the soil becomes warmer than the air, causes vertical thermal convection currents to develop within the boundary layers. This introduces turbulence or instability that acts to move the chemical signature up into the free air. When the molecules are moved into the free flow of the air, the effect is to reduce the concentration by dilution. Conversely, when the soil surface is cooler than the air, thermal convection is inhibited, with the result that the molecules are effectively trapped in the boundary layer. This effect is strengthened by the cooling of the air adjacent to the surface, which increases its viscosity. Higher viscosity lowers the Reynold s number, thus decreasing boundary layer thickness. 

POLYDIMETHYLSILOXANE. A silicone polymer developed for use as a dielectric coolant and in solar energy installations, It also may have a number of other uses. It is stated to be highly resistant to oxidation and biodegradation by microorganisms. It is degradable when exposed to a soil environment by chemical reaction with clays and water, by which it is decomposed to silicic acid, carbon dioxide, and water. 

Table 2 gives the composition of a representative soil sample from each landing site. The composition of the soils from the various locations can also be compared with the results of the chemical analyses of the lunar surface made by the unmanned space probes, Surveyor V, VI, and VII (Table 1), and the data from the x-ray fluorescence experiment (Table 4). The latter experiment made use of the fluorescence x-rays emitted from the lunar surface due to excitation by the solar x-rays which were measured on the Command Service Module of Apollo 15 during its orbit around the Moon. In this way values for the Al/Si and Mg/Si ratios were obtained for large areas of the lunar surface.27 ...

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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