Soil chemical changes

Billet, M.F., Parker-Jarvis, F., Fitzpatrick, E.A. and M.S.Cresser (1990). Forest soil chemical changes between 1949/50 and 1987. Journal of Soil Science,... 

CU-CUSO4 electrodes with saturated CUSO4 solution are recommended for potential measurements in soil. Their potential constancy is about 5 mV. Larger errors can be traced to chemical changes in the CUSO4 solution. These electrodes have been developed for long-life applications in potential-controlled rectifiers and built-... 

The weathering process which eventually reduces the rock of the parent material to the inorganic constituents of soil comprises both physical and chemical changes. Size reduction from rocks to the colloidal state depends not only upon the mechanical action of natural forces but also on chemical solubilisation of certain minerals, action of plant roots, and the effects of organic substances formed by biological activity. 

EPIC is designed to simulate relevant biophysical processes simultaneously and realistically, using readily available input data and accepted methods. It is capable of simulating plant and soil response for hundreds of years, and it is applicable to a wide range of soils, climates, and plants. EPIC also simulates soil erosion and soil chemical and physical property changes over centuries. The time limit for simulation of hydrologic parameters is restricted only by the availability of high-quality climate input data. 

Turner FT, Patrick Jr WH. Chemical changes in waterlogged soils as a result of oxygen depletion. Trans. 9lh Intern. Cong. Soil Sci. 1968 4 53-65. 

Plant roots and root-induced chemical changes in the rhizosphere strongly affect the bioavailability of trace elements (Hinsinger, 1999). First, root-induced changes in the ionic equilibria influence the bioavailability of trace elements. The differential rates of plant uptake of water and ions in the soil solution result in a depletion or an accumulation of the ions in the... 

Dinkelaker B., Hahn G., Romheld V., Wolf G.A, Marschner H. Non-destructive methods for demonstrating chemical changes in the rhizosphere 1. Description of method. Plant Soil 1993 155/156 67-70. 

Fenn L.B., Assadian N. Can rhizosphere chemical changes enhance heavy metal absorptuin by plants growing in calcareous soil Proceedings of the 5th International Conference on the Biogeochemistry of Trace Elements 1999 Julyll-July... 

The transition from conventional to organic and low-input farming is accompanied by changes in an array of soil chemical properties and processes that affect soil fertility. Fundamental differences, both qualities and quantitative, in the flow and processing of nutrient result from the use of cover crops, manure and compost applications, and reduction or elimination of synthetic fertilizers and pesticides. These changes affect nutrient availability to crops either directly by contributing to nutrient pools or indirectly by influencing the soil chemical and physical environment. 

Both direct and indirect methods are used in studying soil chemistry. While in all cases direct methods are preferable, it is not always possible to make direct observations of all the chemical species, and physical and chemical changes of interest. Thus, it is often necessary to modify the soil before analysis. In many cases, it is essential to extract components before analysis can be carried out. It is also possible to obtain valuable information about the chemistry of soil by carrying out analyses that destroy all or a part of the soil matrix. A summary of analysis types and instruments commonly used in soil analysis is given in Table 8.1. 

Razafinjara AL. 1999. Cation-anion balances and chemical changes in the rhizosphere of rice in an iron toxic soil. PhD thesis. University of the Philippines at Los Banos. 

Johansson, M. Stenberg, B. Torstensson, L. Microbial and chemical changes in two arable soils after long-term sludge amendments. Biol. Fert. Soil 1999, 30, 160-167. 

Soil colloids are capable of adsorbing most allelopathic chemicals. Such adsorption would result in temporary loss of toxin activity. Chemical changes could occur during adsorption that would permanently deactivate the toxin. The adsorption reactions are usually reversible, however, so that some or all of the toxin would still be available for uptake by a receiver plant. 

Landmine signature chemicals change form, chemical properties, and eventually become eliminated from soil systems by microbiological and soil mineral degradation reactions. 

Clarke, M.S., Horwarth, W.R., Shennan, C. and Scow, K.M. 1998. Changes in soil chemical properties resulting from organic and low-input farming practices. Agronomy Journal 90 662-671. 

Hinsinger, P. 2001. Bioavailability of soil inorganic P in the rhizosphere as affected by root-induced chemical changes a review. Plant and Soil 237 173-195. 

While in lab experiments or on-site the pH can be controlled, in an in situ application it will always decrease due to the formation of organic acids. This will effect shifts in the oxidation mechanism toward the direct oxidation pathway and in the chemical equilibrium of the soil. Furthermore, both ozone applications will result in changes in the soil chemical constituents, i. e. the cation exchange layer and the humic fraction. The consequences of these changes are still mostly unknown. A special lag-phase and a selection of bacteria in regrowth might be caused by the ozonation. 

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