Note: Descriptions are shown in the official language in which they were submitted.
PCT APPLICATION AS AMENDED
PROCESS FOR PRODUCING A SOIL-CONDITIONING AGENT 2 ~ 3
The invention relates to a process for manufacturing of a granu-
lated product for amelioration of soils being damaged and/or
defective, especially for use in agriculture and forestry.
In recent years an increasing deterioration of the growth and
health of various plants has been observed. Larger parts of
forest stand have got sick.
There are already larger forest areas in which the trees do not
present any practical growth, leafs and needles turn yellow, fall
off and die without additional external operations. Essentially
the same is true in the field of agriculture.
The reasons for said deficiencies in forests have not been clari-
fied totally but can be explained by the influx of harmful sub-
stances from the atmosphere, causing a decrease in the pH-values
within said soils and furthermore relate to malfunction of
nutrient circulation in vegetation.
In this context the so-called "sour rain", i.e. the load of soils
with SO2 or similar substances plays an important role.
Especially in forests the nutrient circulation plays an important
role. The trees absorb essential nutrients from the soil by their
roots, part of which is hold in newly formed wood, branches and
needles, while an important larger part is emitted via branches,
needles or leafs and then washed off by rain and transported back
into the soil. Furthermore high amounts of nutrients are trans-
ported back to the soil surface via leafs and needles, falling
down, via fruits, dead branches and barks. While it has been
thought in former times that nutrient supply for the wood could
be secured by this for ever it is known today that this is not
true especially for those places with pure or downgraded soils or
those areas in which the nutrient circulation is disturbed by
insufficient change of raw humus or spreaded use as well as in
areas with high air pollution.
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In addition factors like the soil type, water addition and water
removal play an important rols with respect to disturbances of
nutrient circulation.
Former tests to increase the soil quality and to adjust the
nutrient circulation correctly are mostly characterized by a
selected mineral fertilisation, in order to add, above all,
nitrogen, phosphorus and potassium, but also magnesium, calcium
and trace elements to the soil.
After it had been noted that the addition of calcium to overaci-
dified soils could not eliminate nutrient deficiencies charac-
teristically lime, containing foreign nutrients has been used
instead of limestone flour. ~ut in any case gypsum is formed
and together with this an inert crust so that an influence with
respect to the pH-value could be achieved but no permanent soil
amelioration.
A physical mixture of a fertilizer and pellets is known from
US-A-4,410,350, the latter being provided to prevent hydration of
said fertilizer and thus crust forming on said fertilizer. In
this respsct the pellets serve as a carrier for the fertilizer or
for absorption of water respectively. They are formed by the dust
from a dolomite furnace and contain large amounts of calcium
oxide beneath magnesiumoxide. The described crust forming is ac-
cepted consciously.
It is the object of the invention to provide a process for manu-
facturing a product for amelioration of soils being damaged
and/or defective to ameliorate the plant growth, especially the
growth of trees effectively and not only for shorter periods but
long-term whereby it is desired to achieve a continuous, time
dependent successive influence of the quality of the so treated
soil.
3 i~
The invention is based on the finding, neglected in former times,
that supply of said soils with an sufficient amount of magnesium
being important for the treatment of damaged or defective soils
and the plants growing in said soils.
Magnesium as an important nutrient has to fulfill various func-
tions in the plant's metabolism. It is a structural part of chlo-
rophylls, ribosomes and cell wall components and is involved as a
co-factor within activation of various enzymes.
It is known from tests that the magnesium content of needles from
a pinetree or a spruce tree must be at least 0,03 percent by
weight to secure a long time survival of the tree (so-called
lethal range).
Repair of said nutrient deficiencies by said known fertilising
methods mentioned above presents only a provisional solution as
the effectiveness of said fertilizers is only short-term.
Furthermore magnesium is presented in known fertilizers mostly as
a salt, for example as MgS04 2 H20 (kieserite) or MgS04 7 H20
(bitter salt), whereby further unwanted active substances like
"S" are taken into the soil.
Furthermore the solubility rate of said magnesium compounds in
said soil is constant for each product, that means that only a
single temporary effect could be achieved.
Furthermore the invention has found that single use of magnesium
carbonate has certain disadvantages. First the solubility of said
carbonate is relatively poor. To increase it materials with high
specific surfaces have to be used. Theoretically the material
could be brought out in corresponding powdered form but as a
2~ ';3
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powder it is difficult to handle and would blow away uncontrolled
if thrown from a plane or being adsorbed by the needles and leafs
if thrown off in a dry state or as a suspension and would get
into the soil only little by little. It is true that preparation
of said carbonates with a binder, for example magnesia cement,
allows an use-specicific manufacturing, but it does not lead out
of the problem that a magnesium release to said treated soils can
only be achieved in long terms and within a relatively short time
interval.
It is true that fertilization with magnesium oxide alone leads to
a quick increase of the Mg content of said soil because of an
remarkably higher solubility with respect to magnesium carbonate
but at the same time problems in manufacturing and time dependent
efficiency arise.
In its broadest embodiment the invention proposes a process in
which fine (powdered) magnesium carbonate is mixed with fine
(powdered) magnesium oxide together with a binder under addition
of water, granulated thereafter and finally the so produced
granules are dried thereafter to prepare a granulate like ame-
lioration product.
Surprisingly the mixture of magnesium oxide and magnesium carbo-
nate does not lead to a physical addition of the predescribed
characteristics but a synergistic combination of both products
takes place as described in more detail hereafter:
An important essential of the invention is that the basic
materials are provided as finest particles. By the high surface
high reaction surfaces are provided. By the addition of water
during mixing of the components this water reacts with MgO under
formation of magnesiumhydroxide which insofar takes over the
function of an in-situ-binder and enables agglomeration and
compactness of the various mixing components during granulation
(pelletizing), without need of any additional binder.
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During subsequent drying, which should be carried out preferably
in a C02-rich atmosphere, whereby corresponding flue gases from a
furnace could be used, a partial carbonization (recarbonization)
of the formed reaction components can be achieved so that the
following components are presented in the ready, dried product:
- MgC03 (from the original mixing component)
- MgC03 (recarbonated material)
- Mg(OH)2 (as a reaction product)
- MgO (from the original mixing component).
As a result of increasing solubility from the carbonate via the
hydroxide to the oxide there a three step reaction mechanism is
offered in one product. That means that different components are
presented in one product which present their effect at different
times in the soil. Surprisingly it has been found that magnesium
carbonate resulting from the original material and now present in
the granules formed presents a lower dissolution than the
recarbonated material being by the way X-ray amorph so that a
fourth reaction step being formed in-situ and all this being
achieved from two common Mg-containing substances in a simple
process, whereby a granule like product being produced that can
be distributed easily and does not blow away because of its high
specific gravity and does not adhere to branches, leafs or need-
les when thrown from a plane but falls immediately down onto and
gets in the soil.
The different solubility coefficients of the various components
of the product lead to the effect that not only a sudden effect,
especially caused by the MgO component is achieved but also a
long time effect up to ten years and more can be achieved (where-
by then namely the carbonate from the original material will de-
velop its effectiveness because of being heavy soluble).
2 ~
It seems obvious that the constituent amounts of the various re-
action components depend from the original mixing ratio of said
magnesium carbonate to said magnesium oxide. This should be pre-
ferably in the range of 10 : 1 to 2 : 1 whereby the exact mixing
ratio can be chosen as a function of the individual soil quality
of the desired time dependent efficiencies respectively.
The finer the material being the higher will be the reaction sur-
face and the higher will be the efficiency of the product. As
well insofar the reaction of the original components with each
other and with water will be influenced. Preferably the original
components should be presented in a fineness of grain less than
200 ~m whereby it is preferred to present more than 50 % by weight
in a fineness of grain less than 40 pm.
In this context it has to pointed out that additional ingredients
can be added to the product and its original components
respectively, if desired, especially to enable even a more
complex soil amelioration. In this context various products are
provided: It is true that small amounts of additional binders can
be chosen but preferably foreign nutrients are added, dependent
of the individual soil quality. Furthermore additional ingre-
dients like zeolithes can be added activating the ion exchange
capacity and/or the water-absorbtion capacity. Finally addition
of small amounts of known fertilizers is possible although the
main aspect of the invention being to present a Mg-containing
product.
As already pointed out above the product can be spreaded manually
or from corresponding vehicles onto the soil but it can as well
be thrown from a plane flying over forests. In ea~h case the use
of the described product does not lead only to a correction of the
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ph-value, dependent on the selected basic materials and their
concentration, but does as well optimize the nutrient circulation
of the plants in those soils which have been treated with the
product.
