Microbes in soil

Most redox reactions in vitro reach equilibrium only extremely slowly with half times of the order of months or years, even though they may be highly favoured thermodynamically. This is illustrated by the persistence of N2 in oxic systems even though its oxidation to NOs is strongly favoured (Table 4.1). However, microbes in soil and water are capable of catalysing particular reactions from which they obtain energy for metabolism. The half times of such microbially catalysed reactions are of the order of hours or days. 

Indigenous microbes in soil partially degraded lindane to carbon dioxide (MacRae et al., 1967). In a 42-d experiment, C-labeled lindane applied to soil-water suspensions under aerobic and anaerobic conditions gave CO2 yields of 1.9 and 3.0%, respectively (Scheunert et al., 1987). 

We also looked at the effect of Bionelle on the population of microbes in the soil. We time-dependently monitored the population of microbes in soil in which... 

Thakali S, Allen HE, Di Toro DM, Ponizovsky AA, Rooney CP, Zhao F-J, McGrath SP, Criel P, van Eeckhout H, Janssen CR, Oorts K, Smolders E. 2006a. A terrestrial biotic ligand model. 2. Application to Ni and Cu toxicities to plants, invertebrates, and microbes in soil. Environ Sci Technol 40 7094-7100. 

II). In soils pretreated up to 4 times with p-nitrophenol, nearly two-thirds of applied parathion was converted to soil-bound residues and 14C02 as compared with 39% in soils with no p-nitrophenol pretreatment. Sudhakar-Barik et al. (19.) observed enrichment of parathion-hydrolyzing microbes in soils treated with p-nitrophenol. 

A key to obtaining the energy in organic compounds, and thus to sustain life, is to obtain an electron acceptor. Higher plants and animals can utilize only 02 as an electron acceptor, but microbes in soils and elsewhere can also utilize the oxidized states... 

Cecchi et al. (2004), however, classihed EDTA, ethyl acetate, methanol, or Mehlich III solutions as harsh extractants that appear to be helpful in determining irreversible sorption of phenolic acids but not bioavailable phenohc acids. I would strongly disagree particularly in regard to neutral EDTA extractions. Our data clearly indicate that this is not the case (see justification above). As a matter of fact it is known that roots and microbes in soil produce a number of chelahng agents that function in a similar manner to EDTA (Nagarajah et al. 1970 Doetsch and Cook 1973 Kaminsky and Muller 1977 Marschner and ROmheld 1996 Fisher 2002 Fisher and Bipp 2002). 

Con 2 Selection and induction of phenolic acids-utilizing microbes in soil occur readily when phenolic acids are present. 

Ouchi, S. (1992). Pollution of Soil and Soil Modifier, Effective Use of Microbes in Soil, Kogyo Gijutsu-kai, pp. 135-161. 

GRAY T.R.G. 1976. Survival of vegetative microbes in soil. Symposium of the Society of General Microbiology, 26, 327-364. 

Nitrate is one of the facts of life. It is essential for the growth of many plant species, including most of those we eat, but it becomes a problem if it gets into water in which it is not wanted. It is perceived mainly as a chemical fertilizer used by farmers, but much of the nitrate found in soil is produced by the microbes that break down plant residues and other nitrogen-containing residues in the soil. There is no difference between nitrate from fertilizer and that produced by microbes, but, whatever its origin, this rather commonplace chemical entity has now become a major environmental problem and is also treated as a health hazard. 

After Flarvest. How do the memory effects shown by the other crops compare with those of winter wheat Winter wheat did not show a memory effect after one year, but oilseed rape does seem to do so. Researchers of the Agricultural Development and Advisory Service found that nitrate production by microbes in the soil after a rape crop increased with the amount of fertilizer given to the crop (R. Sylvester-Bradley, personal communication). One reason may lie in this crop s habit of shedding its leaves as harvest approaches, which means that the microbes in the soil get early access to these residues. This habit might contribute to the apparently smaller efficiency of this crop in using nitrogen fertilizer. The crop may be just as efficient as winter wheat at taking up the fertilizer but drops... 

In soil and sediments, methyl parathion adsorbs to soil and is expected to display moderate mobility (EPA 1980c). The major degradation process of methyl parathion in soil is biodegradation by microbes (Badway and El-Dib 1984). Degradation by hydrolysis has been observed to occur at higher temperatures... 

Molecular analysis of the interaction between plants, microbes, and soil components may help us understand the causal relationships of events taking plaee in the rhizosphere. Nevertheless, due to the necessity to simplify the experimental approaches, we still do not have the complete picture that takes into ae-count the relative weight of each factor. 

In general, one would expect that every enzyme will be released close to the roots either by roots or by microbes and eventually will be immobilized in rhizo.sphere soil. If a given enzyme activity has not yet been measured in rhizosphere soil, this is likely more due to the lack of specifically devoted studies or suitable methods than to a real absence. For example, a recent study has first developed an assay for myrosinase in soil and, second, has hypothesized the... 

Recurrent is the lack of adequate techniques to assess carbon flows through the plants and microbes into soil organic matter (151). Most important is the development of techniques and protocols to separate rhizosphere from nonrhizosphere soil as well as possibly to facilitate analyses of soil carbon dynamics. The use of carbon isotopes, and, where possible, application of double labeling with C and C, seems inevitable in order to separate the contribution of different substrates to the formation of the soil organic matter pool and to get to an understanding of the ecological advantage of exudates and rhizodeposits. 

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