Soil-phenolic acid

It is also important to understand that most allelopathic effects apparently result from the combined actions of several allelochemicals, often with each below a threshold concentration for impact. In allelopathic situations which implicate phenolic acids, soil concentrations have ranged from below 10 to above 1000 ppm for each compound. The lower end of the spectrum is below a concentration required for an effect in current bioassays. Additive and synergistic effects have been demonstrated, however, for combinations of cinnamic acids (102), benzoic acids (103), benzoic and cinnamic acids (10 ). and -hydroxybenzaldehyde with coumarin (105). It appears that such combined interactions may be very important under field conditions. 

Sparling, G. P., Ord, B. G. and Vaughan., D., 1981. Changes in microbial biomass and activity in soils amended with phenolic acids. Soil Biol. Biochem. 13, 455-460... 

Recovery of phenolic acids by NaOH from amended soil samples was equal to or greater than those recovered from non-amended soil samples. The difference (minus approximately 0.01 p,mol/g soil) in recovery between amended and non-amended phenolic acid soils represented a portion of the amended phenolic acids (i.e., 1 M NaOH extractable) that had been irreversibly sorbed during the equilibration and/or incubation periods. Values for 1 M NaOH extractable phenolic acids from non-amended soils were < 0.0017 xmol/g soil for Cecil B (0.2% organic matter) soil samples and ranged from 0.013 xmol/g soil for ferulic acid to 0.073 p,mol/g soil for p-coumaric acid in the Cecil A (3.7% organic matter) soil samples. Differences between amended and non-amended soils ranged from 0 xmol/g soil for p-coumaric acid to 0.024 p,mol/g soil for ferulic acid in Cecil A soil samples and 0.013 p,mol/g... 

However, there is one more caveat for both total and individual phenolic acids. Soil extractions recover residual or net concentration, i.e., input - losses, for a point or various points in time. Since both input and losses are unknown between points of time the actual available total or individual phenolic acid concentrations in soil over time are also unknown. The concentrations of available phenolic acids interacting with roots could thus be greater, at times much greater, or lower, at times much lower, than the net concentrations determined from soil extracts. 

SHINDO H. and KUWATSUKA S. 1975. Behavior of phenolic substances in the decaying process of plants. III. Degradation pathway of phenolic acids. Soil Science and Plant Nutrition, 21, 227-238. 

Sulphates, silicates, carbonates, colloids and certain organic compounds act as inhibitors if evenly distributed, and sodium silicate has been used as such in certain media. Nitrates tend to promote corrosion, especially in acid soil waters, due to cathodic de-polarisation and to the formation of soluble nitrates. Alkaline soils can cause serious corrosion with the formation of alkali plumbites which decompose to give (red) lead monoxide. Organic acids and carbon dioxide from rotting vegetable matter or manure also have a strong corrosive action. This is probably the explanation of phenol corrosion , which is not caused by phenol, but thought to be caused by decomposition of jute or hessian in applied protective layers. ... 

M. J. Krogmeier and J. M. Bremner, Effects of phenolic acids on seed germination and. seedling growth in soil. Biol. Fertil. Soil ftll6 (1989). 

T. Makino, Y. Takahashi, Y. Sakurai. and M. Nanzyo, Influence of soil chemical properties on adsorption and oxidation of phenolic acids in soil suspension. Soil Sci. Plant Nittr. 42 U1 (1996). 

D. Vaughan, M. V. Cheshire, and B. G. Ord, Exudation of peroxidase from roots of Festuca rubra and its effects on exuded phenolic acids. Plant Soil I60 i53 (1994). 

Although there is no doubt as to the importance of mycorrhizae in nutrient absorption, reviews on ion uptake have generally not considered it. Hatling et al. (143) made this same point more than 10 years ago. In addition, although phenolic acids inhibit phosphate (144, 145) and potassium (146) uptake, no work has examined the effects of these compounds on nutrient absorption of mycorrhizal associations. Since soil microorganisms produce the bulk of the volatile compounds emitted from soil, which are known to inhibit or stimulate fungal development (147-148), this group of compounds from microbial sources should receive more attention. 

Soil microorganisms produce many compounds that are potentially toxic to higher plants. Examples include members of the following antibiotics (1-6), fatty and phenolic acids (7-12), amino compounds (13-15), and trichothecenes (16, 17). "Soil sickness" and "replant problems" have been reported where certain crops or their residues interfere with establishment of a subsequent crop (18, 19). Toxins resulting from microbial activity sometimes are involved, but it is often unclear whether these are synthesized de novo in microbial metabolism or are breakdown products of the litter itself (20). 

Total Phenolics and Phenolic Acids in Plants and Soils 155... 

DETERMINATION OF TOTAL PHENOLICS AND PHENOLIC ACIDS IN SOILS... 

Djurdjevic, L., Dinic, A., Mitrovic, M., Pavlovic, P. and Tesevic, V. (2003). Phenolic acids distribution in a peat of the relict community with Serbian spruce in the Tara Mt. forest reserve (Serbia). European Journal of Soil Biology 39 97-103. 

Hennequin, J. R. and Juste, C. (1967). Presence of free phenolic acids in soil Study of their influence on germination and growth of plants. Annual Agronomy 18 545-... 

Katase, T. and Kondo, R. (1984). Distribution of different forms of some phenolic acids in peat soils in Hokkaido, Japan 1. Trans-4-hydroxycirmamic acid. Soil Science 138 220-225. 

Phenolic acids can be allelopathic but their presence in soil is ephemeral due to rapid degradation and/or sorption by soil particles (Inderjit 2004). Sorption of benzoic acid onto soil particles increased with concentration and it may explain the reason for the limited allelopathic effect of benzoic acid at concentrations often recorded in natural soil (Inderjit 2004). Microorganisms help to generate allelochemicals, but they may also modify toxic compounds into nontoxic compounds (Khanh et al. 2005). Allelochemicals are changed in composition and quantity during the residue decomposition. Allelopathy plays an important function in nutrient recycling (Rice 1984). 

Available data indicate that phenol biodegrades in soil under both aerobic and anaerobic soil conditions. The half-life of phenol in soil is generally less than 5 days (Baker and Mayfield 1980 HSDB 1997), but acidic soils and some surface soils may have half-lives of between 20 and 25 days (HSDB 1997). Mineralization in an alkaline, para-brown soil under aerobic conditions was 45.5, 48, and 65% after 3, 7, and 70 days, respectively (Haider et al. 1974). Half-lives for degradation of low concentrations of phenol in two silt loam soils were 2.70 and 3.51 hours (Scott et al. 1983). Plants have been shown to be capable of metabolizing phenol readily (Cataldo et al. 1987). 

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