|Title of Invention||
"METHOD FOR STERILISING SOILS AND APPARATUS THEREFOR"
|Abstract||The present invention relates to a method for sterilizing soils and of the apparatus related thereto. The method comprises sequentially at least the following phases;-dispersion into the soil of at least one compound, solid, liquid or gaseous, able to react exothermically with water and/or steam, or other substance; - injection of at least one jet of water and/or steam, or of another substance, into the soil in such a way as to produce heat in the subsequent reaction with the compound. Between the two aforesaid phases it is convenient to proceed to break up the soil to favour its mixing with the compound and create the best conditions for the reaction. The apparatus (10) suitable to carry out this method comprises autonomous locomotion means (1) to be able to reach the open countryside, a tank (2) to transport water or another suitable substance and a related appendage (5) to convey it into the soil, a second tank (3) for the compound that is to react exothermically with water and/or steam, or, in general, with the substance transported in the first tank (2), and means (4) for dispensing the compound into the soil. It can also be provided with a boiler (6) to heat or vaporize the reactanl contained in the tank (2), as well as an agricultural tool (8) to favour the mixing of the compound, the penetration of the reaetant into the soil and the subsequent reaction thereof.|
|Full Text||The present invention relates to a method for sterilising soils and to apparatus therefor
The growing specialisation in crops and the so-called single-crop systems, particularly widespread in the sector of ornamental plants, garden vegetables, corn and beet, generate a strong interaction between the microflora of the soil and the radical system of the plants. Moreover, numerous vegetable and animal parasites can survive in the soil even for many years, until they come in contact with plants prone to suffer from their pathogenetic action.
The continued cultivation of such plants in the same soil thus leads to ailments in their growth and to a progressive deterioration in harvest yields. The first and most ancient way to obviate this problem consists of the so-called "crop rotation" or, more generally, of prolonging the interval during which a crop remains absent from a soil. In this situation, the soil dwelling parasites of the plant itself progressively die due to "starving".
However, there are cases wherein the "rotation" method does not provide sufficient reliability: many parasites are able to survive as parasites of other plants or remaining in a state of quiescent life; other times, abandoning a certain crop for a given period may not be economically advantageous. It is then necessary' to resort to rather energetic interventions, which must therefore be applied only on the bare soil, some time before planting a new crop. These are rather onerous processes that accomplish the disinfection or disinflation by means of
chemical or physical interventions.
Chemical interventions consist of the administration of fungicides, insecticides, plant protection products or fumigation products: such intervention are long, very costly and highly hazardous for environmental pollution. After their execution, rather long time intervals are required before it is possible to proceed with the cultivation of the treated soil.
Physical interventions essentially consist of administering heat to the soil, heat which can be produced and distributed in various ways. As a rule, regardless of the methods used, heating the soil up to 80^0 °C is sufficient to kill all parasites present. This type of operation allows to start cultivation a short time afterwards, as soon as the temperature of
the soil drops to 2^0 °C.
Among physical interventions, treatments with dry heat, performed by heating the soil in the so-called country ovens, are the least effective ones, both because the results they yield are not always satisfactory, and because in any case they can only be applied to small plots of land. Sterilisation with boiling water entails prohibitive expenses and it is only plausible for very small plots of land.
Steam treatment finds applications for soil disinfection in greenhouses, stable seed-beds or small open plots: it can be accomplished both introducing the soil into large cement tanks, or in other containers, then passing through the soil both the steam produced by a generator and fixed or movable tools positioned on or within the soil to be disinfected. In this latter case, the steam, produced by an appropriate generator, moves through pipes which lead it to the aforesaid dispensing tools of
various designs. Use is made of hood dispensers, similar to upside down
cases or to canvas sheets with the edges stuck in the soil, wherein the
steam is inserted, or even comb dispensers, comprising a horizontal pipe
wherefrom a series of vertical pipes depart which convey the steam into
the soil. Hood dispensers are particularly indicated when the sterilisation
has to reach depths in the order of 2025 cm, comb dispensers for
greater depths. Lastly it is possible to use large self-propelled machines,
able to intervene autonomously.
Only sufficiently profitable cultivations, for instance floriculture, justify
the use of this system which presents, for wide open spaces, logistically
The object of the present invention therefore is to eliminate the
drawbacks mentioned above.
The invention, as it is characterised by the claims, solves the problem of
making soil sterilisation practically feasible also in wide open spaces,
for instance in the country, exploiting known chemical reactions of the
One of the advantages obtained through the present invention consists
essentially of the fact that energy consumption for steam production, or
for water heating, is drastically reduced. Consequently, lighter machines
can be used which, on one hand, contribute further to reduce
consumption, on the other hand make it easier to carry out the
sterilisation in the open country.
Another important advantage consists of the fact that, to perform the
exothermic reaction, it is possible to employ substances which are
beneficial to the soil also from other viewpoints, for instance to redress
its pH balance or to fertilise it. The result of the exothermic reaction could even be in turn a substance acting as a fertiliser for the soil thus treated.
According to the invention there is provided a method for sterilising soils, comprising an exothermal reaction within the soil, between a first substance such as supplementer, a fertilizer, a compound with porous microstructure, quicklime, caustic soda, potash, natural or synthetic zeolites or ortho phosphoric acid and a second substance such as water or steam , for killing organisms in soil.
According to the invention there is also provided an apparatus for sterilising soils, comprising autonomous means of locomotion, supporting a tank for transporting a reactant, at least an appendage to convey it into the soil, a second tank for a compound which reacts exothermically with said reactant and means for dispensing said compound into the soil, and optionally means for heating said reactant and means for dispersing reactant into soil.
The invention is described in more detail hereafter with the aid of the drawing which shows an embodiment provided purely by way of non limiting example, in which:
Figure 1 shows a schematic side view of the apparatus.
As can be observed in the Figure, the apparatus (10) comprises autonomous means of locomotion (1), a tank (2) for transporting a reactant, for instance water, and at least one appendage (5) to convey such reactant into the soil. Since for displacements in the open country the apparatus (10) described must be able to move freely, the aforesaid means of locomotion (1) can consist of a tractor or of an engine integral to the chassis of the apparatus (10) itself.
In order to produce an exothermic reaction within the soil, the apparatus (10) further comprises a second tank (3) for a compound that is to react exothermically with water and/or steam, or with any other suitable substance, and means (4) for dispensing said compound into the soil.
Since the heat produced by the chemical reaction is affected by the compound used, and the latter may vary according to other requirements, solid sterilization, i.e. the suppression of the parastes, will be obtained by injecting water or another substance at an optimal temperature to be assessed on a case by case basis. Therefore, it may be necessary to heat the water or even to vaporise it before injecting it into the soil. To this end, the apparatus (10) can comprise a boiler (6), able to vaporise the water to be injected into the soil or, more in general, to raise the
temperature of the reactant.
Since it is certainly desirable to create the best conditions for a uniform sterilization of the soil, the latter could be broken up beforehand with a mechanical hoe or a harrow. The optimal solution however consists of providing the apparatus (10) in question with an agricultural tool (8) such as the aforesaid ones, interposed between the means (4) for dispensing the compound which is to react exothermically with the reactant contained in the first tank (2) and the appendage (5) to convey such reactant into the soil, so as to disperse the compound into the soil and favour the penetration therein of water and/or steam, or, in general, of the substance used.
The apparatus (10) described above is functional to carry out a method to sterilize soils, also new and original, which could be carried out also with other machinery while still maintaining its innovative characteristics. Such method comprises sequentially at least the following phases:
-dispersing into the soil at least one compound able to react exothermically with water and/or steam, or other suitable substance;
-injecting at least one jet of water and/or steam into the soil, or of another substance, in order to obtain an exothermic reaction with the compound previously dispersed therein.
As has been mentioned above, it is convenient for the method to comprise, between the dispersion of the compound and the injection of water and/or steam, or of any other substance, an intermediate phase consisting cf breaking up the soil, in order to favour the dispersion of the compound and to create the best conditions for the exothermic reaction
to take place.
The compound, usable in solid, liquid or gaseous form, could
advantageously be constituted by a fertiliser or a supplementer, i.e. by a
substance that is also able to re-balance the nature of the soil, towards a
greater acidity or a greater alkalinity, depending on the crops to be
Purely by way of example, one could use quicklime (CaO), caustic soda
(NaOH) and caustic potash (KOH) for acid soils or orthophosphoric acid
(H3PO4) for alkaline soils. While the former give rise with water (H2O)
to strongly exothermic reactions, wherein hydroxyl ions (OH") are freed
which raise the pH value, orthophosphoric acid reacts exothermically
with water producing hydrogen ions (H+) which reduce the pH value. In
all examples mentioned above, moreover, essential substances for the
development of the crops are released in ionic forms, respectively
calcium, sodium, potassium and phosphorus.
Alternatively, to heat the soil, exothermic reactions could be provoked
using materials with porous microstructure or natural or synthetic
To these substances could be added a neutral substance, such as a
fertiliser of natural origin rich in organic substances and in micro-
organisms useful to the plants, particular well suited for restoring the
bacterial tnicrofiora, for the most part eliminated by the heat produced
in the course of the sterilisation.
The invention thus conceived can be subject to numerous modifications
and variations, without thereby departing from the scope of the inventive
concept. Moreover, all components may be replaced with technically
In practice, modifications and/or improvements are obviously possible
without thereby departing from the scope of the following claims.
1. A method for sterilising soils, comprising an exothermal reaction within the soil,
between a first substance such as supplementer, a fertilizer, a compound with porous
microstructure, quicklime, caustic soda, potash, natural or synthetic zeolites or ortho
phosphoric acid and a second substance such as water or steam , for killing organisms in soil.
2. A method as claimed in claim 1, wherein the first substance is dispersed in the soil
beforehand and the second substance is injected in the soil subsequently.
3. A method as claimed in claim 1, optionally comprising an intermediate phase
consisting of breaking up the soil between the dispersion of the compound and injection of
water or steam in order to favour the dispersion of the compound and to facilitate the
4. An apparatus for sterilising soils, as claimed in claim 1, comprising autonomous
means of locomotion (1), supporting a tank (2) for transporting a reactant, at least an
appendage (5) to convey it into the soil, a second tank (3) for a compound which reacts
exothermically with said reactant and means (4) for dispensing said compound into the soil,
and optionally means for heating said reactant and means for dispersing reactant into soil.
5. An apparatus for sterilising soils as claimed in claim 4, wherein the means for
heating said reactant comprise a boiler (6), able to raise the temperature of the reactant to be
injected into the soil or to vaporise it.
6. An apparatus for sterilising soils, as claimed in any of the preceding claims, wherein
said means for dispersing the reactant into the said comprise a soil breaking up tool (8),
interposed between said means (4) for dispensing the compound and said appendage (5) for
conveying the reactant into the soil, in such a way as to disperse the compound into the soil
and to favour the reaction therein.
7. A method for sterilising soils, substantially as hereinbefore described with reference
to the accompanying drawing.
8. An apparatus for sterilising soils, substantially as hereinbefore described with reference to the accompanying drawing.
|Indian Patent Application Number||452/DEL/1998|
|PG Journal Number||10/2008|
|Date of Filing||20-Feb-1998|
|Name of Patentee||ALCE GARDEN S.R.L.,|
|Applicant Address||VIA PENNABILLI N.-15, 47100 FORLI (FO), ITALY.|
|PCT International Classification Number||A01G 11/00|
|PCT International Application Number||N/A|
|PCT International Filing date|