Agriculture Reference
In-Depth Information
In nature, the most common are calcium-magnesia (alkaline earth) species. Calcium and
calcium-magnesian bentonites can be translated into the category of sodium by treatment with
solutions of sodium salts. These sodium bentonites are called activated, and the process is
called ion exchange replacement by activation.
In the pure form of bentonite clay is used rarely, mostly in industry and other areas of the
economy are used bentonite mud powder. This material is obtained by drying and small
crushing bentonite clay. Bentonite mud powder is added in the polymeric material, admixed
to the concrete, which considerably increases the strength of adhesion between theirs
dissimilar phases. On the basis of bentonite powder produced the most affordable drilling
mixtures having high performance and providing excellent results in a vertical or horizontal
drilling. Bentonite mud powders in combination with refractory materials are the main raw
material for the manufacture of natural sand blend. Depending on the proportions of mud
powder and perlite such mixtures may have different properties. Sand blend based on
bentonite clay is differ high durability, optimum gas-tight, herewith easy formed and environ-
mentally friendly. Bentonite clay is also known as bentomat - material used for waterproofing
of various objects. This material is very easy to operate and can be used in most weather
conditions, including at low temperatures. Equally important is the use of bentonite clays in
the preparation of means for cleaning oil-products, various oils, wines, as well as raw
materials for the production of heat and waterproofing materials (Petrov, 1980).
The largest deposits of bentonite are located in the US. (Black-Giles, Sanders-Defiance),
Canada, Great Britain, Armenia and Ukraine. Russia also has significant reserves of raw
bentonite and its territory is home to more than 300 deposits of bentonite and bentonite-
containing clays (Volga region, Transcaucasia, Central Asia, Far East, etc.).
But only a small part of them (about 10%) explored in detail, and their reserves are
considered All-Union Geological Fund. Stocks in these deposits are defined in the amount of
544.8 million tons (including forming, adsorption, etc.). Stocks of most valuable alkaline
bentonite clays are only 50 million tons (Gradusov, 1976). The largest producers and major
exporters of bentonite are now the United States, Greece, Japan, Italy, Argentina, Spain.
Thus, bentonite clays have a number of unique properties that defined their wide
application in various fields of human activity. However, in agriculture their current use unfairly
restricted. The most widely studied their role as the major secondary minerals that make up the
soil-forming material, and many kinds of soils (Gorbunov, 1978; Gradusov, 1976). There are
also a number of studies on the use of bentonite as a filler in various pesticides (Petro, 1980),
and in animal breeding as a valuable animal feed additives (Antipov et al., 2010; Burihonov,
1992).
Promising sector of the use of clays is reclamation light (sandy and sandy loam) soil. This
agricultural practice long been known to farmers, but the information on the effectiveness of
quite contradictory and fragmented. This is due to the different composition of clays in use
and different environmental conditions (soil, climate, and production).
This direction of the use of bentonite clays in agriculture has been studied by the author
from 1991 to 1997. According to the results of research was defended the Candidate's
dissertation in 1997 (Lednev, 1997). At present being studied a new direction using of clay
minerals - as effective ameliorants for remediation of soils contaminated with heavy metals.
Bentonite clay is a multifunctional ameliorant and therefore it has diverse effects on soil
properties. Most researchers studied the high and very high doses of this ameliorant 100 -
200 t-ha
-1
(Buzmakov and Lamzin, 1971; Lgotski, 1979; Sharafeeva, 1980).
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