Enhanced soil microbial activity

Laboratory Generated Enhanced Soil Microbial Activity... 

Chemical weathering of minerals during pedogenesis can be enhanced by microbial activity by a factor as high as 106 (Kurek 2002). Microorganisms can dissolve minerals by direct and indirect actions under aerobic and anaerobic conditions (Robert and Berthelin 1986 Ehrlich 2002 Kurek 2002). In some cases of attack, the microorganisms may be dispersed in the soil solution in others, they may grow in biofilms on the surface of susceptible minerals. 

The long-term view on soil fertility management with its emphasis on the enhancement of SOM is a major case for organic farming. This holds all the more true in SSA, where SOM largely determines soil CEO, pH and Al toxicity in many regions (Schlecht et al., 2006). SOM contains practically all N and 20-80% of all P in the surface horizons of tropical African soils (Bationo et al., 1998), and it positively affects infiltration rate, water holding capacity and soil microbial activity. 

Braddock JE, ML Ruth, PH Catterall, JL Walworth, KA McCarthy (1997) Enhancement and inhibition of microbial activity in hydrocarbon-contaminated arctic soils implications for nutrient-amended bioremediation. Environ Sci Technol 31 2078-2084. 

The Earth Tech technology is an ex situ, soil bioremediation process that uses the indigenous microorganisms already present in the soil in a custom-designed approach to enhance microbial activity. The Earth Tech technology is used primarily to treat soil contaminated with petroleum hydrocarbons from fuels (such as gasoline, diesel, kerosene, etc.). In the Earth Tech process. 

This chapter describes the effects of dc fields on ions transport in soils, electrolysis and geochemical reactions, microbial adhesion and transport, and microbial activity. The interest in these in these processes is derived from the potential of using electric fields for transporting and mixing contaminants, biostimulants, and bioaugmentation inoculants to enhance in situ bioremediation. 

Another solid-phase treatment involves the same approach to enhancing microbial activity but relies on a different way of providing O2. Here, additional air is provided by vacuum extraction of soil above the water table (i.e., the vadose zone or the unsaturated soil layer), thereby supplying the terminal electron acceptor needed by the aerobic bacteria. This process, designed for hydrocarbon-contaminated sites, is termed bioventing or simply venting. 

Any factors that stimulate the growth of soil microorganisms or that increase the availability of pesticides in soil will enhance the degradation of the chemical. Felsot et al. (1981) found that the persistence of carbofuran was inversely correlated with microbial activity in corn-cropped soils. Tu and Miles (1976) reported that 88% of parathion was lost from soil in 7 months diazinon, 92% lost in 20 weeks paraoxon, 100% hydrolyzed in 12 hr mala-thion, 50-90% lost in 24 hr and carbofuran, 50% lost in 3-50 weeks. 

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