・ Volcanic ash may be natural fertilizer through weathering ( efflorescence )
Natural volcanic ashes are quite full of adsorption, they fall with various metallic ions and gases.
During an eruption, not only large quantities of vapors but also various gases such as carbon dioxide, nitrogen, hydrogen sulfide, sulfur dioxide, chlorine are issued from a crater.
They selectively adsorb various matters dependently on individual natures.
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After the eruption, for a while from the fall, those volcanic ashes are harmful for plants because of contained toxic metallic ions and gases.
But, as a long time goes from the accumulation of volcanic ashes, its chemical nature varies from alkalescence to acidity.
Furthermore, those volcanic ashes gradually weather and begin to show various properties according to climates proper to the region.
Namely, due to physical and chemical actions such as raining, sunbeam, heat, snow and frost or biological actions with microbes, bugs and various plants & animals, toxicities of volcanic ashes are neutralized, those ashes are purified and those materials themselves change into different compositions from original states.
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Therefore, in most of lands over volcanic ashes, transmuted fertile soils are found out.
In some regions, completely barren lands could be changed into even jungle-covered lands.
We think that such cases are originated in effective fertilizer-ingredients issued from volcanic ashes under weathering-metamorphosing processes.
It seems that features of transmuted volcanic ashes remarkably depend on each climate proper to individual region, compositions and characters of fallen volcanic ashes, its fertilizing-effects also have diverse aspects.
At present, we don't know about conditions and actions to transmute some volcanic ash into an other material and how to bring fertilizing effects to the land in detail ( in 2009 ).
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By the way, it's probable that nitrogen gives main influence on fertilizing effects of volcanic ash.
When volcanic ashes are released against the air from a volcano and drift in the air, they effectively adsorb nitrogens in the earth's crust and the air.
Just after the fall or for a while from the fall, those volcanic ashes cause damages for plants because of contained noxious matters.
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However, as those volcanic ashes are gradually weathered, much fertilizing-effects appear.
Because adsorbed nitrogens effectively work.
By the way, as an extremely strong fertilizer also withers plants, the concentration of the nitrogen fertilizer must be moderately diluted to obtain best effects.
Therefore, it's often reported that the more distant the interval from a crater gets and the longer the time from the fall of volcanic ash becomes, the higher the fertilizing effect also is.
It's probable that such a spatio-temporal 'distance' contributes to the dilution of the concentration.
Really, it's probable that volcanic ashes work as natural nitrogen fixater to produce nitrogen fertilizers.
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Furthermore, the same mechanism as this case holds in snow.
Namely, the same as volcanic ash, snow also has very subtle and complex crystalline structure at micro level and it's full of adsorption.
In snowing, the snow takes in large quantities of nitrogens from the air through adsorption and then it brings fertilizing-effects to the soil.
Following cases are presented as such evidences.
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In the case of Japanese rice crop, the crop of rice per unit in snowing regions on the side of the Japan Sea is higher than that on the side of the Pacific Ocean.
In particular, we can have a good harvest in a heavy snowfall-year.
In the snowing regions on the side of the Japan Sea, although only one time of rice crop is executed a year, the crop quantity is far greater than that of a triple cropping region.
It's supposed that
・ Weathered volcanic ashes such as green tufas plentifully distributed on the side of the Japan Sea work as a kind of fertilizer.
・ Nitrogens brought by snowfall as well as the climate of hot and high humidity in a summer season proper to this region influence the soil.
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・ Various applications of weathered volcanic ash
Zeolite is one of the weathered and transmuted volcanic ashes under characteristic environmental conditions.
Industrial worlds have paid attention to zeolite as one of the inorganic industrial materials until now.
Its main ingredients are silicon oxide SiO2 , aluminum oxide Al2O3 , calcium oxide CaO , sodium oxide NaO , kalium oxide K2O and water H2O , etc, these are very similar to ingredients of natural volcanic ash, therefore, it's supposed that partial ingredients of the volcanic ashes were dissolved and transmuted.
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It's well-known that this zeolite can be transformed into glass by heating it at comparatively low temperature and it turns out to be a foamed state by dehydrating it.
In Japan, the distribution of zeolites roughly agrees with that of tuffs which were ejected from active volcanos in the Miocene and heaped on the ground.
And, various physical, chemical, biological actions on the layer of tuffs remarkably contributed to the generation of zeolites.
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At present ( about 2009 〜 2010 ), it's known that in Japan, good zeolites are widely distributed over Tohoku region and regions under which green tuffs are buried are mainly found out on the side of the Japan Sea.
And, as volcanic ashes were transformed into zeolites through various weathering-transmutation actions, they are distributed over the desert region of the South-West of the North America, the Great Rift Valley of the East-North Africa and East Europe , etc , world-widely.
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Furthermore, following features of zeolite have been pointed out by some researchers.
1. It contains zeolite-waters and large quantities of waters.
2. Its specific gravity is comparatively small and large gaps are formed in the dehydrated state.
3. It has cation-exchange properties.
4. It has same cavities as molecules in size, and it can adsorb gases & waters.
5. It has catalytic actions.
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Various ways to use it on above properties have been considered and executed.
Properties of this zeolite also depend on environments and climates.
Applied cases of zeolite at present are as follows ( about 2009 〜 2010 ).
( a ) Soft-clay for paper-manufacturing ( filler )
( b ) Separation-chemicals ( to separate oxygen from nitrogen and to adsorb SO2-gas )
( c ) Demoisture chemicals
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( d ) Ion-exchange for wastewater treatment
( e ) Soil-conditioner ( for improving soil and increasing holding-abilitiy of nitrogen fertilizer )
( f ) Materials for preventing granular fertilizer from hardening ( preventing granular fertilizer from losing moisture with covering )
( g ) For fodder ( killing bad smells such as deodorizing and drying excretions, wastewater treatment, mixing them with fodders )
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( h ) Catalytic carrier ( chemical treatment for NO2-gas similar to oxidation-catalyzer, the use of zeolite as catalyst )
( i ) Other industrial uses ( softening chemicals for hard water, adsorption chemicals for toxic gas, absorber for bad smell, treatment for toxic wastewater, etc )
As mentioned in the above, many and various applications have been considered and performed.
