FUMIGATION APPARATUS

The present invention concerns a method of 5 fumigating an agricultural soil and the related fumigation apparatus.

BACKGROUND

The disinfestation or sterilization of an agricultural soil is a practice that allows the soil to 10 be cleaned from both animal and plant parasites residing therein and that can cause damage to agricultural crops.

For carrying but this practice, different physical or chemical systems are available, including

15 solarization, the injection of vapour into the soil or the treatment with chemical substances having a "fumigating" action, said substances also called fumigants which, when appropriately distributed on the soil or incorporated therein, perform their 20 antiparasitic action.

Fumigants are products that have the characteristic of being able to exist in the gaseous state, under certain temperature and pressure conditions, in a concentration and for an amount of 25 time sufficient to allow the elimination of the parasites of interest present in the soil.

A fumigant can be applied to an agricultural soil by introducing the fumigant into the soil irrigation system so that the fumigant is distributed as a mixture 30 with the irrigation water. Advantageously, the irrigation system is a micro-flow-rate irrigation system, also known as drip fumigation system. With respect to traditional application systems, drip fumigation systems guarantee greater efficiency of the fumigating agent, as it reaches the soil area occupied by the root apparatus of the crops more quickly, where it reacts by gasifying, hence preventing the product from remaining localized on the surface.

The drip fumigation system generally includes one or more perforated tubes (also called "drip tapes") arranged on the crop beds, on which one or more emitters are installed. For mixing it to the irrigation water, the fumigant is sucked or pumped from a storage tank and injected in predetermined doses into the water circulating in the irrigation system through a withdrawal/injection system. The fumigant storage tank can be connected to the injector system, e.g. by means of a Venturi tube .

Fumigant storage tanks are made of rigid, corrosion-resistant material, e.g. polypropylene.

The fumigant, which is transported from the production site to the cultivation area inside hermetic containers (e.g. cans) , is transferred into the storage tanks connected to the irrigation system. The transfer operation is repeated whenever necessary, e.g. when the storage tank is empty.

However, since fumigants are generally volatile compounds that irritate the skin and eyes, as well as corrosive and sometimes flammable, they must be transferred from the hermetic containers for transportation to the storage tanks by specialist operators equipped with suitable personal protective devices .

Therefore, despite the excellent efficacy of the fumigating agents, the control of phytopathogens in agricultural crops through fumigation is currently a complex process to manage and that implies high costs.

In consideration of the aforesaid state of the art, the Applicant therefore has set out as main objective identifying a new method for applying fumigants to an agricultural soil, that is simpler and cheaper to carry out .

In particular, an object of the present invention is to provide a fumigation method that reduces as much as possible the exposure of operators to fumigating agents, so as also to limit their resorting to the use of personal protective devices .

DESCRIPTION OF THE INVENTION

The Applicant has now found that the aforesaid objects and others, which will be better illustrated in the following description, can be achieved by a method of fumigating an agricultural soil wherein the fumigant to be supplied to the irrigation system is collected by a replaceable hermetic cartridge, which is connected to the irrigation system through at least one flow control valve, which regulates the outflow of the fumigant from the cartridge and the subsequent supply of fumigant to the irrigation system.

Once the cartridge has been installed, the flow control valve is activated to allow the outflow of the fumigant and its injection into the irrigation system. After use or, for example, when the cartridge is consumed, the valve is deactivated for interrupting the flow of fumigant and then replaced with a new cartridge. In this way, the transfer operations of the fumigant from the container used for transporting the product from the production plant to the place of use to the corresponding storage tank are avoided, substantially limiting - if not even completely eliminating - the exposure of the operators to the fumigant vapours. The present invention further makes the presence of fumigant storage tanks superfluous, thus simplifying the layout of the fertirrigation system.

The Applicant has also found that it is particularly advantageous to use a cartridge wherein the fumigant is contained inside a bag made of flexible material, i.e. inside a bag that can collapse onto itself due to the effect of atmospheric pressure following the outflow of the fumigant which is supplied to the irrigation system. In fact, the use of a cartridge comprising such a flexible bag makes the collection of the fumigant more effective, as it reduces the quantity of residual fumigant that inevitably remains in a consumed cartridge compared to a cartridge in which the fumigant is contained inside a container made of a rigid material .

Advantageously, it has been found that bags made of flexible material suitable for the above-described use are those known in the state of the art for transporting edible liquids (e.g. wine, beer, oil, etc . ) , in particular in the form of packaging known as "bag-in-box", where the bag is housed inside a rigid box, e.g. made of card or metal, so as to facilitate the transport thereof .

According to a first aspect, the present invention therefore relates to a method of fumigating an agricultural soil that comprises the steps of: A) connecting at least one first cartridge containing at least one fumigant to an irrigation system for irrigating said soil, said cartridge being hydraulically connected to said irrigation system through at least one valve for controlling the supply of said fumigant in said irrigation system;

B) activating said valve to allow the supply of said fumigant in said irrigation system;

C) bringing the fumigant into contact with said soil through said irrigation system;

D) when required, deactivating said valve to stop the supply of said fumigant in said irrigation system and removing said first cartridge;

E) repeating one or more times the steps A-D with a second cartridge containing at least one fumigant .

According to a second aspect, the present invention concerns an apparatus for fumigating an agricultural soil comprising:

- at least one irrigation system for irrigating said soil,

- at least one replaceable cartridge comprising at least one hermetic bag made of a flexible material containing at least one fumigant,

said replaceable cartridge being hydraulically connected to said irrigation system through at least one valve for controlling the supply of said fumigant in said irrigation system;

said hermetic bag being able to collapse onto itself due to the effect of atmospheric pressure following the supply of said fumigant in said irrigation system.

According to a third aspect, the present invention concerns the use of a hermetic bag made of a flexible material, which can collapse onto itself due to the effect of atmospheric pressure following the outflow of the contents thereof, as a replaceable cartridge for supplying at least one fumigant to an irrigation system of an agricultural soil.

For the purpose of the present description and appended claims, the term "flexible material" used with reference to the material that forms a hermetic bag for containing a liquid indicates that the material that forms the bag is able to collapse onto itself due to the effect of atmospheric pressure following the outflow of the liquid contained therein, in particular by suction or pumping; the collapse of the bag causes the progressive reduction of the internal volume of the bag and consequently the increase in pressure exerted by the gaseous phase (e.g. air or inert gas) present above the liquid.

For the purpose of the present description and appended claims, the term "rigid material" used with reference to a hermetic container for containing a liquid indicates that the material that forms such container does not undergo any substantial deformations following the outflow of the liquid contained therein, i.e. deformations such as to cause a significant reduction of the internal volume of the container.

For the purpose of the present description and appended claims, the verb "comprise" and all the terms deriving therefrom also include the meaning of the verb "consist" and of the terms deriving therefrom.

The limits and numeric ranges expressed in the present description and appended claims also include the numeric value or numeric values mentioned. Furthermore, all the values and sub-ranges of a limit or numeric range must be considered to be specifically- included as if they had been explicitly mentioned.

According to the fumigation method according to the present invention, a first cartridge containing the fumigant is hydraulically connected to an irrigation system through at least one valve for controlling the supply flow of the fumigant from the cartridge to the irrigation system, where the fumigant is mixed with the irrigation water to be distributed onto the soil.

The flow control valve is configured at least for:

- allowing the flow of fumigant from the cartridge to the irrigation system (valve activated) ;

interrupting the flow of fumigant from the cartridge to the irrigation system (valve deactivated) .

Preferably, the flow control valve also allows the volumetric supply flow rate of fumigant to the irrigation system to be regulated.

The flow control valve may be of the one-way or two-way type. In a preferred embodiment, the flow control valve is a two-way valve, i.e. a valve that allows the controlled flow of a fluid, in particular a liquid, at the inlet to the cartridge or the outlet from the cartridge.

The two-way valve, for example, allows the cartridge to be washed, e.g. with water, after its use, thus simplifying the cartridge disposal, recovery and/or recycling operations.

The flow control valve may be of the type known to a person skilled in the art, e.g. : disc valve, membrane valve, diaphragm valve, needle valve, shutter valve, butterfly valve and the like. The flow control valve may also be electrically activated (solenoid valve) .

Preferably, the fumigant flow control valve is integrated into the body of the cartridge, i.e. it is an integral part of the cartridge and is removed therewith upon the replacement of the cartridge. In that case, the irrigation system preferably comprises a connector that can be connected to said valve for hydraulically connecting the cartridge and the irrigation system.

Alternatively, the fumigant flow control valve can be integrated into the irrigation system. In this case, the cartridge preferably comprises a connector that can be connected to said valve for hydraulically connecting the cartridge and the irrigation system.

Examples of materials that can be used for manufacturing the valves are: HDPE, LLDPE, PP, EVOH, PA.

When required, e.g. because the cartridge is consumed or in the event that a different fumigant is to be applied to the soil, the control valve is deactivated for stopping the flow of fumigant from the cartridge towards the irrigation system.

When the valve is deactivated, the cartridge can be removed without the outflow of fumigant. The removed cartridge can be replaced with a new cartridge, repeating the operations described above for connecting and using the previous cartridge.

Preferably, the cartridge comprises a hermetic bag made of flexible material, which can collapse onto itself due to the effect of atmospheric pressure following the outflow of the fumigant, which is supplied to the irrigation system.

Advantageously, the aforesaid bag is hosted inside a container made of rigid material, e.g. cardboard, so as to form a cartridge of the "bag-in-box" type.

The flexible material that forms the hermetic bag can be selected from those known in the state of the art, in particular from those used in the food sector for packaging liquid products such as wine, beverages, oil, etc.

Preferably, the cartridge has an available volume for containing fumigant within the range of 1 litre to 1000 litres.

Preferably, the flexible material is a multilayer material comprising two or more thermoplastic polymeric films, laminated to each other or coextruded.

In one embodiment, when the cartridge comprises a bag made of flexible material for containing the fumigant, said bag comprises at least one opening onto which at least one spout is attached or welded; the bag further comprises a removable closure cap, that can be associated with said spout, comprising the aforesaid fumigant flow control valve.

The flexible material may be a multilayer material that comprises at least three layers, each formed by a film made of thermoplastic polymeric material; preferably, the number of layers is within the range from three to ten, more preferably within the range from three to seven, even more preferably the multilayer flexible material consists of three layers.

In one embodiment, the flexible material is a multilayer material comprising:

- an outer layer, i.e. having a surface facing towards the external environment, formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polypropylene, polyamide and copolymers thereof, said materials being optionally metallized;

- at least one intermediate layer formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polyamide and related copolymers, said film being optionally metallized; or said intermediate layer consists of a sheet of aluminium;

- an inner layer, intended to come into contact with the fumigant, formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polyamide and related copolymers, said film being optionally metallized .

In another embodiment, the flexible material is a multilayer material comprising:

an outer layer formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polypropylene, oriented polyamide (OPA) and ethylene vinyl alcohol copolymer (EVOH) ; or said outer layer consists of laminated polypropylene,

- at least one intermediate layer formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polyester, metallized polyester, polyamide, ethylene vinyl alcohol copolymer (EVOH) ; or said intermediate layer consists of a sheet of aluminium; an inner layer formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene, polyethylene, polyamide and ethylene vinyl alcohol copolymer (EVOH) , said film being optionally metallized.

In a particularly preferred embodiment, the flexible material is a multilayer material formed by:

an outer layer formed by a thermoplastic polymeric film comprising polyethylene or an oriented polyamide film (OPA) ;

- an intermediate layer formed by a thermoplastic polymeric film wherein the polymeric base comprises at least one polymer selected from: polyethylene terephthalate, ethylene vinyl alcohol copolymer (EVOH) and linear low-density polyethylene (LLDPE) , said film being optionally metallized; and

- an inner layer formed by a thermoplastic film comprising polyethylene, e.g. linear low-density polyethylene (LLDPE) .

The aforesaid polymeric films, as well as the polymeric base comprising one or more of the polymers and copolymers described above, may comprise one or more conventional additives, such as plasticizers, pigments, UV stabilizers, etc.

The term "polyethylene" according to the present invention means polyethylene (PE) , high density polyethylene (HDPE) , low density polyethylene (LDPE) , medium density polyethylene (MDPE) and linear low- density polyethylene (LLDPE) .

The term "metallized polyester" according to the present invention means polyester coated with a thin layer of metal, generally aluminium.

The term "polyamide" according to the present invention means polyamide, oriented polyamide (OPA) , Nylon 6, Nylon 6.6, Nylon 4.6, Nylon 6.9, Nylon 11, Nylon 12.

The chemical composition of thermoplastic polymeric films, in particular those that form the outer and intermediate layers, gives the multilayer flexible material protection against the penetration of UV radiation and limits the permeation of oxygen from the external environment; in fact, UV radiation and oxygen could degrade the fumigating agent contained inside the container, making it less effective in controlling the phytopathogens of the agricultural crops of interest .

The flexible materials described above have high resistance against the corrosive power of fumigants. This makes the bags produced with such materials suitable for the storage of fumigating products having a pH in a wide range of values .

To maximize the chemical and also the mechanical resistance of such containers, the thermoplastic films described above having a thickness within a wide range of values can be used.

Preferably, the inner layer in contact with the product has a thickness comprised between 40 pm and 120 pm, more preferably between 60 pm and 100 pm, even more preferably about 80 pm.

Preferably, the at least one intermediate layer has a thickness comprised between 5 pm and 100 pm, more preferably between 20 pm and 80 pm, even more preferably about 55 pm. Preferably, the outer layer has a thickness comprised between 5 pm and 40 pm, more preferably between 10 pm and 20 pm, even more preferably about 15 pm.

The flexible materials described above can be produced using any known method in the state of the art such as, for example, methods known for producing thermoplastic films, e.g. polyethylene. Such methods are based, for example, on (co) extrusion and blowing, (co) extrusion cast and lamination techniques .

Further information on the materials, the structure and the techniques that can be used for producing the flexible material bags described above can be found, for example, in US 2016/304332 A1.

The present invention can be used for fumigating a soil with the fumigating agents known in the art, without any particular limitations. Preferably, the fumigant is a substance that is liquid at ambient temperature (25 °C) .

Examples of fumigants for agriculture that can be used according to the present invention are: 1,3- dichloropropene, chloropicrin, metarn sodium, metam potassium, methyl isothiocyanate, allyl isothiocyanate.

The fumigant is preferably selected from: 1,3- dichloropropene, chloropicrin, methyl isothiocyanate, allyl isothiocyanate and mixtures thereof.

For practical uses in agriculture, it is often preferable to use the aforesaid fumigants appropriately formulated in agronomic compositions (fumigating compositions) . Preferably, a fumigating composition comprises at least one fumigant, at least one solvent and/or diluent, optionally one or more agronomically acceptable co-formulants .

The fumigating compositions are prepared according to known methods, e.g. by diluting or dissolving the active substances in at least one solvent and/or diluent means, possibly in the presence of one or more surfactants. The diluent may be liquid or solid, at ambient temperature .

Examples of inert solid diluents (also called supports) are: kaoline, alumina, silica, talc, bentonite, gypsum, quartz, dolomite, actapulgite, montmorillonite, diatomaceous earth, cellulose, starch, etc .

Examples of liquid diluents are: water; organic solvents, such as: aromatic hydrocarbons (xylols, mixtures of alkyl benzoles, etc.), aliphatic hydrocarbons (hexane, cyclohexane, etc.) , halogenated aromatic hydrocarbons (chloro benzole, etc.) , alcohols (methanol, propanol, butanol, octanol, etc.) , esters (isobutyl acetate, etc.), ketones (acetone, cyclohexanone, acetophenone, isophorone, ethyl amyl keton, etc.) ; vegetable oils; mineral oils and mixtures thereof .

Examples of liquefied diluents or liquefied substances, which gasify at ambient temperature and pressure are propellent gases, such as butane, propane, halogenated hydrocarbons, nitrogen or carbon dioxide.

Examples of surfactants that can be used for the purposes of the present invention are: non- ionic wetting agents and emulsifiers (alkylphenol polyethoxylates, fatty alcohol polyethoxylates , etc.), anionic wetting agents and emulsifiers (alkylbenzene sulfonates, alkyl sulfonates, etc.), cationic wetting agents and emulsifiers (quaternary alkyl ammonium salts , etc . ) .

Dispersing agents can also be added to the fumigating composition (e.g. lignin and salts thereof, cellulose derivatives, alginates, etc.) and stabilizing agents (e.g. antioxidants, UV ray absorbing etc.).

The overall concentration of the fumigant in the fumigating composition can vary within a wide range and depends on different factors. It varies according to the fumigating compound, the specific application for which the fumigating composition is intended, the environmental conditions and the type of formulation adopted. In general, the total concentration of fumigants is in the range from 0.1% to 99% by weight with respect to the total weight of the fumigating composition, preferably from 0.5 to 97% by weight.

The total quantity of fumigant to be applied for obtaining the desired effect can vary according to different factors such as, for example, the compound used, the crop to be protected, the degree of infestation, the climatic conditions, the soil characteristics, the application method, etc.

Doses of fumigant in the range from 50 1 to 2000 1 per hectare of agricultural crop generally provide sufficient control.

Doses of fumigant within the range from 75 1 to 1500 1 per hectare of agricultural crop are preferably used.

The irrigation system can be both of the surface type (the irrigation water containing the fumigant is distributed on the surface of the agricultural soil) and of the subsurface type (the irrigation water containing the fumigant is incorporated into the agricultural soil) .

The irrigation system is preferably a drip fumigation system.

Preferably, the drip fumigation system comprises one or more perforated tubes (also called "drip tape") arranged on the agricultural soil and on which one or more emitters are optionally installed.

For mixing the irrigation water, the fumigant is preferably withdrawn from the cartridge and injected in predetermined doses into the irrigation water through an injector system. The injector system preferably comprises at least one Venturi tube by means of which the fumigant is sucked from the cartridge and mixed with the irrigation water. As will appear clear to a person skilled in the art, the present invention can also be used to distribute on an agricultural soil, agronomic compositions other than the fumigating compositions described above such as, for example, insecticides, nematicides, herbicides, fungicides or biostimulants, with analogous benefits to those observed for the fumigating compositions.

Examples of insecticides and nematicides that can be applied to the soil through the aforesaid hermetic bag are abamectin, acetamiprid, clothianidin, dimethyl disulfide, dinotefuran, emamectin, fluazaindolizine, fluensulfone, fluopyram, flupyradifurone , fosthiazate, imidacloprid, nitenpyram, oxamyl, thiacloprid, tioxazafen, 2- (3,4,4, -trifluoro-3 -butenylsulfonyl) -5- methyl-1, 3 , 4 -tiadiazole , 2- (3,4,4, -trifluoro-3 - butenylsulfonyl) -5 -isopropyl-1 , 3 , 4 -tiadiazole .

Examples of herbicides that can be applied to the soil through the aforesaid hermetic bag are rimsulfuron and sulfosulfuron.

Examples of fungicides that can be applied to the soil through the aforesaid hermetic bag are benalaxyl, benalaxyl-M, fluopyram, fosetyl-aluminium, metalaxyl, metalaxyl-M, propamocarb.

Examples of biostimulants that can be applied to the soil through the aforesaid hermetic bag are mixtures of amino acids and/or oligopeptides of animal and/or plant origin, ectoine, phytosterols, mixtures of nitrogen, phosphorus and potassium compounds known as NPKs, algae, humic acids, fulvic acids, stillage and molasses .