WO2005022983A1

WO2005022983A1 - A soil sterilising and weed-killing method and apparatus

Info

Publication number: WO2005022983A1
Application number: PCT/IB2004/002803
Authority: WO
Inventors: Alfredo Celli
Original assignee: Alce Garden S.R.L.
Priority date: 2003-09-05
Filing date: 2004-08-30
Publication date: 2005-03-17
Also published as: ITBO20030519A1

Abstract

Method and apparatus for treating soil, in particular for sterilising and/or weed-killing treatment of soil, especially for agricultural purposes. It is provided that the soil is lifted into the air and the sterilising substance is placed in contact with the soil while the latter is being lifted into the air.

Description

A SOIL STERILISING AMD WEED-KILLING METHOD AND APPARATUS

Technical field The present invention relates to a method and apparatus for treating soil, in particular for sterilising and/or weed-killing treatment of soil, especially for agricultural purposes.

Background of the invention Prior art teaches the use of apparatuses comprising means for loosening up the soil and means for sterilising the soil where said soil sterilising means comprise means for emitting at least one sterilising substance deep into the soil. These prior art apparatuses, however, are not totally effective in sterilising and/or destroying weeds, especially in the surface layer of the soil.

Summary of the invention It is therefore provided a soil treatment method, in particular for sterilising and/or weed-killing treatment of soil, especially for agricultural purposes; where at least one sterilising and/or weed-killing substance is applied to the soil; the method being characterised in that the soil is lifted into the air and in that the sterilising substance is applied to the soil while the soil is suspended in the air. Also provided is an apparatus for treating soil, in particular for sterilising and/or weed-killing treatment of soil, especially for agricultural purposes; the apparatus comprises supporting means, means for loosening up the soil and means for sterilising the soil; the means for sterilising the soil comprising means for applying at least one sterilising and/or weed-killing substance to the soil, the apparatus being characterised in that the means for loosening up the soil consist of means for lifting the soil into the air and in that the means for applying the sterilising substance apply said sterilising substance to the soil while the latter is suspended in the air. The resulting sterilising and/or weed-killing treatment of the surface layer of the soil is especially effective.

Brief description of the drawings These and further advantageous technical characteristics of the apparatus and method according to the invention are clearly described in the claims below, these technical characteristics being nevertheless more apparent from the detailed description which follows, with reference to the accompanying drawings which illustrate a preferred embodiment of the invention provided merely by way of example without restricting the scope of the inventive concept, and in which: - Figure 1 is a schematic and partly sectional side view of a first preferred embodiment of the apparatus according to the present invention; - Figure 2 is a schematic cross section of the first preferred embodiment of the apparatus according to the present invention; - Figure 3 is a schematic and partly sectional side view of a second preferred embodiment of the apparatus according to the present invention.

Description of the preferred embodiments of the invention It is advantageously provided a method for treating soil, in particular for sterilising and/or weed-killing treatment of soil, especially for agricultural purposes, the method essentially comprising the following steps: loosening up the soil and applying, or releasing, a sterilising and/or weed-killing substance to the soil . Further, in the method it is advantageously provided that the soil to be treated is lifted into the air and the sterilising substance is applied to the soil while the latter is being lifted into the air. In practice, the sterilising substance is brought into contact with the soil while the latter is in a broken up condition, this being an especially effective manner of enabling the sterilising substance to permeate the soil. Preferably, for breaking up the soil, the invention comprises a step of pulverising the soil which breaks the soil up into fine particles of suitably small size. In practice, in the method of the invention, the soil is broken up from a compacted condition to a loosened up condition. More specifically, the method comprises a step of lifting the soil from a rest position on the ground to a loosened up condition in the air. Advantageously the sterilising substance is released during the upward movement imparted to the soil by the soil loosening up means, which are described in more detail below. According to an advantageous aspect of the invention, a second sterilising substance is applied to the soil and is designed to react with the first sterilising substance. This second substance is released at the soil loosening up means. More specifically, the second substance is released onto a part of the soil where the soil is being loosened up. Preferably, the second substance is released substantially at the point where the soil loosening up means, consisting of a tiller (described in more detail below) start breaking up the soil. Figures 1 and 2 illustrate a preferred embodiment of an apparatus 10 according to the invention for treating soil 12, in particular for sterilising and/or weed-killing treatment of soil for agricultural purposes . The apparatus is drawn or towed by a suitable vehicle in the direction indicated by the arrow A in Figure 1. The apparatus comprises supporting means embodied by a mounting frame 14 and means for loosening up the soil . The means for loosening up the soil consist, more specifically, of means for breaking up the ground which crush the soil 12 into small pieces, preferably reducing it to very small particles. Reducing the soil 12 to fine particles or powder is especially preferred. The means for breaking or loosening up the soil also constitute means for moving the soil 12 and, in particular, for lifting the soil 12 into the air. They consist of means for lifting the soil from a rest position on the ground to a suspended condition in the air. More specifically, they are means which break the soil up from a compacted condition to a loosened up condition. Preferably, the means for loosening up the soil are embodied by a soil tiller 16 that rotates, preferably, at a speed of between 25 and 400 revolutions per minute and that is equipped with a plurality of tools 18 for engaging and breaking up the soil 12, each comprising a first portion 20, extending radially, and a second portion 22, extending transversally from the free end of the first portion 20 of the tool. The tools 18 are transversally distributed on a central mounting shaft 24, which is in turn mounted on the frame 14 through side bearings 26 and 28. The reference numeral 30 in Figure 2 denotes a motor for rotationally driving the tiller in the angular direction indicated by the arrow R in Figure 1. The layer of the soil treated is the layer near the surface down to a maximum depth of 15 to 20 cm from the surface of the ground. Means are also provided for containing the soil in the working condition, these containment means being embodied by the mounting frame 14, which forms a cover that, together with the underlying soil 12, creates a soil sterilising chamber 32, as described in more detail below. The cover comprises an upper containment portion 34 and a rear containment portion 36 pivoted at 38 and forced downwards by suitable adjustable elastic means that are not illustrated in the accompanying drawings . The cover also comprises a first lateral containment portion 39 and a second lateral containment portion 40 which partly penetrate the soil . Under or inside the cover, the soil is lifted into the air in the form of crushed, granular or powdered particles which are dispersed and scattered far apart. Under these conditions, sterilising and/or weed-killing operations are especially effective. Means for sterilising the soil are also provided. The soil sterilising means comprise emitting means for applying a sterilising and/or weed-killing substance to the soil, hereinafter referred to as first sterilising substance or primary sterilising substance. The primary sterilising substance consists of heated water or, preferably, steam emitted by a boiler at a temperature, preferably, of between 50 and 90°C. Further, the steam is discharged by the boiler at a pressure, preferably, of between 5 and 11 bar. Means are also provided for emitting a second soil sterilising substance which reacts exothermically with the first sterilising substance. The second substance is preferably CaO (Calcium oxide) . This substance, might, however, also be like the one described in US patent No. US 6,183,532 and in patent application No. WO 02/07502 in the name of the applicant hereof. Advantageously, the means for emitting the first sterilising and/or weed-killing substance are designed to apply the sterilising substance to the soil while the latter is in the loosened up condition. More specifically, the soil sterilising means apply the primary sterilising substance to the soil while the latter is lifted into the air. This permits uniform and virtually complete contact between the sterilising substance and the soil so that the sterilising and/or weed-killing treatment of the surface layer of the soil is performed very effectively. For crops such as lettuces with root systems that remain close to the surface, the conditions of the surface layer of the soil are critical to obtain good crop yields. In addition, the temperature of the sterilising substance is not so high as to cause irreparable damage to the soil . On the contrary, the fact that the temperature of the sterilising substance in the method according to the invention is not excessively high advantageously allows the soil to be biologically regenerated in a very short length of time. The steam emitting means comprise at least one nozzle 41, and, more specifically, a plurality of nozzles 41 for emitting the sterilising substance and transversally spaced in such a way as to apply the substance uniformly as the towing vehicle moves forward. More specifically, the nozzles for emitting the sterilising substance are located above the soil lifting means, at the downstream end of the latter, and emit the sterilising substance during the upward movement imparted to the soil 12 by the soil lifting means . Said nozzles for emitting the sterilising substance face the inside of the upper cover 34 and are made in a tubular element 42 that extends transversally above and against the cover 34 and has a plurality of holes made in its lower surface 44. The transversal tube is fed from both sides by tubular end sections, only one of which - labelled 46 - is illustrated in Figure 1. As illustrated, the holes 41 that emit the first sterilising substance are arranged in such a way as to apply the sterilising substance to at the rear end of the tiller that lifts up the soil. The soil sterilising means comprise means for containing the sterilising substance and consisting preferably of a tank mounted on the towing vehicle and therefore not illustrated in the accompanying drawings. The tank feeds the water to a boiler, not illustrated in the drawings, which is connected to the inlet of the emitting means through respective hoses, also not illustrated in the drawings, made of rubber, plastic or other suitable material. The aforementioned means for emitting the second sterilising substance comprise at least one opening, and, more specifically, a plurality of openings or apertures for emitting this substance and transversally spaced in such a way as to apply the substance uniformly as the towing vehicle moves forward. The means for emitting the second sterilising substance allow this second substance to fall at the means for loosening up the soil 12 and, more specifically, at an area upstream of the loosening up means . Looking in more detail, the means for emitting the second sterilising substance allow this second substance to fall at an area L of the soil 12 while the latter is being lifted by the soil 12 loosening up means, as illustrated in Figure 1. The means for emitting the second sterilising substance allow this second substance to fall at a point where the tiller starts breaking up the soil 12. Thus, the second substance is mixed into the soil 12 as the tiller moves forward and is optimally distributed in the soil. As illustrated, the second sterilising substance is allowed to fall at the front of the tiller or soil loosening up means . The second soil sterilising means comprise means for containing the second sterilising substance, consisting of a tank or hopper 52 extending transversally over the upper mounting frame . There is also a single duct 54, for conveying the product out of the hopper. The duct 54 extends transversally, is connected at it its top end to the bottom of the hopper, has made in it a plurality of transversally distributed openings through which the sterilising product is discharged to the ground being treated, and at its bottom end leads to a single long slot 50 made in the cover 34. The size of the apertures for discharging the product from the hopper can be adjusted so that the quantity of product discharged from the hopper can be regulated as needed. In the accompanying drawings the reference numeral 60 denotes means for connecting the apparatus according to the invention to a towing vehicle, said means 60 comprising suitable arms to be hitched to the towing vehicle. Also provided are means for mulching the soil, comprising a roller 70 and other elements which are not shown in the drawings. Advantageously, the invention contemplates the provision of a second flow of the first soil sterilising substance conveyed to a different area of the soil from that treated by the first flow of sterilising substance emitted by the nozzles 41. For this purpose, in accordance with another preferred embodiment 100 of the invention, illustrated in Figure 3, there are second means for emitting the first substance, these second means being defined by a steam emitting bar 102 which discharges the steam deeper into the soil, thus also sterilising parts of the soil where deeper crop roots grow. This steam bar might, for example, be like the one described in patent application No. WO 02/07502 in the name of the applicant hereof and the disclosure of which is incorporated herein by reference . For convenience and clarity, the other components of Figure

3 which are the same as the ones of the first preferred embodiment are labelled with the same reference numerals and are not described again in detail . As illustrated, the holes 41 that emit the first sterilising substance are arranged in such a way as to be aligned, along the vertical, with the bar 102 for in-depth emission of the steam. The first sterilising substance may be applied to the soil by the second and first emitting means alternately or, preferably, by the second emitting means simultaneously with the first emitting means. Thus, sterilisation of the layer of soil concerned can be accomplished very effectively in quicker time. Suitable adjustment means, not illustrated in the drawings and consisting for example of hand-operated valves, are provided for directing or dividing the flow of water or steam from the single boiler to the first or second means for emitting the first substance. In practice, to achieve a more effective sterilising or weed-killing effect on the surface, a larger quantity of the first substance can be directed to the first emitting means, which treat the upper layer of the soil, than to the second sterilising means, which treat the deeper layers of the soil. On the contrary, to achieve a more effective sterilising or weed-killing effect in depth, a larger quantity of the first substance is directed to the second emitting means, which treat the deeper layers of the soil, than to the first sterilising means, which treat the surface layer of the soil. The division of the flow of the first substance between the first and second emitting means thus depends on the type of crop to be grown. In other terms, it depends on the layer of the soil to be sterilised more effectively, on the type of root system of the crops to be grown and on the type of pests or weeds to be eliminated which may be present at the surface or deeper down in the soil. The division of the flow of the first substance between the first and second emitting means will also depend on the characteristics of the soil being treated, determining whether the first substance will be divided equally between the first and second emitting means or allowed to flow in larger quantities to the first or to the second emitting means. In the case of sandy soils, the flow might be divided almost equally. Heat travels more quickly and easily through sandy soils and therefore, if sterilisation is to be concentrated on the surface layer of the soil, it is sufficient to send to the first emitting means a little more of the first sterilising substance than that sent to the second emitting means, which work deeper down, while maintaining a substantially equal division of flow between the first and second emitting means. On the other hand, if sterilisation is to be concentrated in the deeper layer of the soil, a little more of the first sterilising substance can be sent to the second emitting means than to the first emitting means, which work at the surface, while again maintaining a substantially equal division of flow between the first and second emitting means . In a clayey soil, however, heat travels more slowly and with greater difficulty. Therefore, to concentrate the sterilising treatment on the surface layer of the soil, the quantity of the first sterilising substance conveyed to the first emitting means must be much greater than that conveyed to the second emitting means, which work in depth. To concentrate the sterilising treatment in the deeper layers of the soil, on the other hand, the first sterilising substance must be conveyed to the second emitting means in much larger quantities than to the first emitting means, which apply the first sterilising substance on the surface . Thanks to the present invention, crops such as lettuces give greatly improved yields even using steam as the only sterilising substance. It should be stressed however that particularly advantageous results can be obtained by using the steam preferably in combination with calcium oxide or with any other suitable substance that reacts exothermically with the steam, as this enables weeds to be totally eliminated from the surface layer of the soil, thus greatly facilitating crop harvesting operations. That means weeds do not need to be removed by hand. Further, the invention permits use of non-toxic, environment-friendly substances. That means the sterilising and/or weed-killing treatment of the surface layer of the soil is performed very effectively and has no harmful effects on the environment . It will be understood that the invention can be modified and adapted in several ways without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements .

Claims

1. A method for treating soil, in particular for performing a sterilising and/or weed-killing treatment of the soil, especially for agricultural purposes; where at least one sterilising and/or weed-killing substance is applied to the soil; the method being characterised in that the soil is lifted into the air and in that the sterilising substance is applied to the soil while the soil is suspended in the air.

2. The method according to claim 1 or according to the preamble to claim 1, characterised in that the substance is applied to the soil while the latter is in a loosened up condition.

3. The method according to either of the foregoing claims, characterised in that it comprises a step of breaking up the soil.

4. The method according to claim 3, characterised in that it comprises a step of reducing the soil to small pieces or fine particles.

5. The method according to claim 3 or 4, characterised in that it comprises a step of pulverising the soil (12) .

6. The method according to any of the foregoing claims, characterised in that the soil is lifted from a rest position on the ground to a raised position where it is loosened up in the air.

7. The method according to any of the foregoing claims, characterised in that the sterilising substance is heated water or, preferably, steam.

8. The method according to any of the foregoing claims, characterised in that the sterilising substance is released during the upward movement imparted to the soil (12) .

9. The method according to any of the foregoing claims or according to the preamble to claim 1, characterised in that a second sterilising substance is applied to the soil .

10. The method according to claim 9, characterised in that the second substance is CaO.

11. The method according to claim 9 or 10, characterised in that the second substance is released at the means for loosening up the soil (12) .

12. The method according to any of the foregoing claims from 9 to 11, characterised in that the second substance is released substantially at the point where the soil (12) starts being loosened up.

13. The method according to any of the foregoing claims, characterised in that in the working condition the soil is contained within a suitable chamber.

14. The method according to any of the foregoing claims, characterised in that it comprises a step of mulching the treated soil.

15. The method according to any of the foregoing claims or according to the preamble to claim 1, characterised in that it comprises a step of supplying at least one second flow of the first soil sterilising substance.

16. The method according to claim 15, characterised in that the second flow of the first sterilising substance is applied to a deeper layer of the soil .

17. The method according to claim 15 or 16, characterised in that the first sterilising substance is applied to the soil by the first and second flows of said first soil sterilising substance simultaneously.

18. The method according to any of the foregoing claims from 15 to 17, characterised in that the flow of the first sterilising substance from a single source is divided into a first flow and a second flow of the first substance.

19. An apparatus (10) for treating soil (12), in particular for performing a sterilising and/or weed-killing treatment of the soil, especially for agricultural purposes; the apparatus comprising supporting means, means for loosening up the soil and means for sterilising the soil; the means for sterilising the soil comprising means for applying at least one sterilising and/or weed-killing substance to the soil, the apparatus being characterised in that the means for loosening up the soil consist of means for lifting the soil (12) into the air and in that the means for applying the sterilising substance apply said sterilising substance to the soil while the latter is suspended in the air.

20. The apparatus (10) according to claim 19 or according to the preamble to claim 19, characterised in that the emitting means apply the sterilising substance to the soil while the latter is in the loosened up condition.

21. The apparatus (10) according to claim 19 or 20, characterised in that the soil loosening up means consist of means for breaking up the soil (12) .

22. The apparatus (10) according to claim 21, characterised in that the means for breaking up the soil reduce the soil to small pieces or fine particles.

23. The apparatus (10) according to claim 21 or 22, characterised in that the soil (12) is pulverised by the breaking up means .

24. The apparatus (10) according to any of the foregoing claims from 19 to 23, characterised in that the lifting means consist of means for lifting the soil from a rest position on the ground to a suspended condition in the air.

25. The apparatus (10) according to any of the foregoing claims from 19 to 24, characterised in that the soil loosening up means consist of a rotary tiller (16) .

26. The apparatus (10) according to any of the foregoing claims from 19 to 25, characterised in that the soil lifting means comprise a plurality of tools (18) for loosening up the soil (12) and comprising a first portion (20) , extending radially, and a second portion (22) extending transversally from the first tool portion (20) .

27. The apparatus (10) according to any of the foregoing claims from 19 to 26, characterised in that it comprises means for containing the soil in the working condition.

28. The apparatus (10) according to claim 27, characterised in that the mounting frame (14) forms a cover which, in combination with the soil (12) below it, creates a soil sterilising chamber (32) .

29. The apparatus (10) according to any of the foregoing claims from 19 to 28, characterised in that the sterilising substance consists of heated water and, preferably, of steam.

30. The apparatus (10) according to any of the foregoing claims from 19 to 29, characterised in that the emitting means comprise at least one nozzle (41) ..

31. The apparatus (10) according to claim 30, characterised in that the emitting means comprise a plurality of nozzles for emitting the sterilising substance, transversally spaced in such a way as to apply the substance uniformly as the apparatus moves forward over the ground.

32. The apparatus (10) according to claim 30 or 31, characterised in that each nozzle for emitting the sterilising substance is located above the soil loosening up means.

33. The apparatus (10) according to any of the foregoing claims from 30 to 32, characterised in that the nozzles for emitting the sterilising substance are located at the downstream part of the soil loosening up means .

34. The apparatus (10) according to any of the foregoing claims from 30 to 33, characterised in that the nozzles for emitting the sterilising substance face the inside of the upper cover (34) .

35. The apparatus (10) according to any of the foregoing claims from 30 to 34, characterised in that the nozzles for emitting the sterilising substance are made in a tubular element (42) that extends transversally above the upper cover (34) .

36. The apparatus (10) according to any of the foregoing claims from 19 to 35, characterised in that the emitting means release the sterilising substance during the upward movement imparted to the soil (12) by the soil lifting means.

37. The apparatus (10) according to any of the foregoing claims from 19 to 36 or according to the preamble to claim 19, characterised in that it comprises means for applying a second sterilising substance to the soil, said means applying a substance that reacts exothermically with the first sterilising substance.

38. The apparatus (10) according to claim 37, characterised in that the second substance is CaO.

39. The apparatus (10) according to claim 37 or 38, characterised in that the emitting means apply the second sterilising substance to the soil at the soil (12) loosening up means .

40. The apparatus (10) according to any of the foregoing claims from 37 to 39, characterised in that the means for emitting the second sterilising and/or weed-killing substance release said second sterilising substance in a part (L) of the soil (12) that is being lifted by the soil (12) loosening up means.

41. The apparatus (10) according to any of the foregoing claims from 37 to 40, characterised in that the means for emitting the second sterilising substance release the second substance at the point where the tiller starts breaking up the soil (12) .

42. The apparatus (10) according to any of the foregoing claims from 37 to 41, characterised in that the second soil sterilising means comprise means for containing the second sterilising substance, consisting of a tank or hopper (52) extending transversally over the upper mounting frame.

43. The apparatus (10) according to any of the foregoing claims from 19 to 42, characterised in that it comprises means for connecting the apparatus to a towing vehicle.

44. The apparatus (10) according to any of the foregoing claims from 19 to 43, characterised in that it comprises means for mulching the soil.

45. The apparatus (10) according to any of the foregoing claims or according to the preamble to claim 19, characterised in that it comprises second means for applying the first soil sterilising substance .

46. The apparatus (10) according to claim 45, characterised in that the second means for applying the first soil sterilising substance apply the substance to a deeper layer of the soil.

47. The apparatus (10) according to claim 45 or 46, characterised in that the second means for applying the first soil sterilising substance apply the sterilising substance to the soil simultaneously with the first means for applying the first sterilising substance.

48. The apparatus (10) according to any of the foregoing claims from 45 to 47, characterised in that the flow of the first sterilising substance from a single source is divided between the first and the second means for applying the first substance.