WO2024089245A1

WO2024089245A1 - Method to treating compacted soils by physical soil amelioration using a rotary drilling system

Info

Publication number: WO2024089245A1
Application number: PCT/EP2023/080073
Authority: WO
Inventors: Abdul MOUAZEN; Ajit BORUNDIA; Muhammad Ali; Amila Hemantha THALAKOTUNAGE
Original assignee: Universiteit Gent
Priority date: 2022-10-28
Filing date: 2023-10-27
Publication date: 2024-05-02

Abstract

The present invention relates to a method to treat compressed soils by physical soil amelioration using a rotary drilling system. Said rotary drilling system comprising a drilling tool with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool; means for rotating the drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to the inlet connection. Said method comprising the step of discharging compressed air into a surrounding medium via the at least one laterally directed outlet opening while simultaneously lowering and rotating the drilling tool. The present invention further relates to tools, machines and vehicles to execute such a method.

Description

METHOD TO TREATING COMPACTED SOILS BY PHYSICAL SOIL

AMELIORATION USING A ROTARY DRILLING SYSTEM

Field of the Invention

The present invention relates to a method to treat compacted soils by physical soil amelioration. The present invention further relates to tools, machines and vehicles to execute such a method.

Background

Agricultural soils are increasingly becoming prone to compaction due to increasing usage of heavy farm machinery on the fields. Deep soil compaction was created during the glacial ages, and in recent times by the ever increasing agricultural machines size, whose mass has reached today to more than 70 tons.

Soil compaction is defined as compacted soil layers, which is a matter of great concern because its negative effects on crop production and environment could be permanent. The topsoil compaction down to 30 cm, can be ameliorated by tillage, or by natural factors e.g. cyclic changes in soils of shrinking and expansion resulting from drying and wetting or freezing and thawing, respectively. Below the topsoil compaction, soil compaction includes hardpans, found between 30-35 cm, created by the wrong use of tillage tools prevents roots and rainwater to penetrate deep in the soil. Unlike topsoil or surface compaction, deep compaction cannot be ameliorated by the natural processes and deep tillage has shown limited influences despite they being very energy demanding and expensive. Moreover, deep tillage operations, despite they are expensive, their successful implementation are limited to dry sandy soils with herbicide resistant weeds on the top soil, although this disturbs the subsoil ecosystem by releasing lots of carbon and nitrogen stored in the subsoils.

The extreme hot and dry summers Europe has seen in the last few years signifies the negative effect of deep soil compaction on crop growth in that the dry and hard soil conditions prevents roots to reach water and nutrients stored deeper than the top 30 cm layer. Under wet conditions, when intensive rainfalls occur in a short period of time, deep compaction slows water infiltration and enhance water runoff, soil erosion and flooding. Object of the Invention

Aspects of the present disclosure are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below.

An object of the invention may therefore be to provide a method to address at least one of the following problems related to subsoil compaction: water runoff and soil erosion as rain water cannot infiltrate into the deeper layers of the soil, farm flooding as water cannot infiltrate deep into the soil, restricted plant root growth leading to reduction in availability and uptake of water and nutrients by the plant, reduced soil aeration leading to reduction in biological activity, denitrification due to increased anaerobic conditions in the soil, poor crop growth and yield, and poor economic return with environmental consequences.

Another object of the invention may therefore be to provide a method to mechanically enhance the root penetrability of the deep hard layers to allow extracting water and nutrients on one hand and improve water infiltration and aeration for a better soil fertility and health on the other hand.

Summary of the Invention

This objective and other objectives which will become apparent from the following description are achieved at least in part by a method, a tool, a system and a vehicle according to the independent claims. Embodiments are defined by the dependent claims.

This objective is achieved by a method for physical soil amelioration using a rotary drilling system. Said rotary drilling system comprising a drilling tool with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool; means for rotating the drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to the inlet connection. Said method comprising the step of discharging compressed air into a surrounding medium via the at least one laterally directed outlet opening while simultaneously lowering and rotating the drilling tool.

Advantageously, the drilled holes with air pressure enabled will aerate the soil, provide a conduit for the rain water to penetrate into deeper layers of soils thereby significantly reducing the chances of water ponding on the fields, reducing the water table by increasing infiltration rates, provide a means of introducing nutrients directly into the soil. The vertical holes created will also allow roots to easily penetrate and proliferate in the deep layers of soil. Further, the drilled holes will induce movement of vital nutrients, air, gases, water laterally from the holes as well as to some extent vertically in the soil by means of potential differences. Thus, the drilled holes will allow the soil to build up a good structure (heal itself) and become healthy.

In addition, the proposed solution is less intensive than ploughing and so is less disturbing to the natural ecosystem. It requires much less energy thereby needing smaller farm machinery to implement the solution. This drilling process also does not need moist soils to work on and can drill on all types of soil especially very dry and hard soils.

The advantages of the discharge of compressed air is that the compressed air will be injected into the surrounding soil and fracture the soil of the compaction layer. The inventors found that by discharging the compressed air while drilling, i.e. simultaneously lowering and rotating the drilling tool, an improved fracture distribution in depth and angular direction could be achieved at high drilling speeds with minimally adaptation (for example only one laterally directed outlet opening) of conventional drilling tools. Furthermore, compressed air makes the whole soil breath as the air travels in the interiors away from the holes. This is good for promoting good root growth and preventing denitrification. Hindering denitrification can reduce air pollution through NO2 emissions that happen when manure is applied on the fields.

The drilling tool comprises a hollow auger having a shaft and a flight that extends radially away from the shaft, wherein the flight comprising a helical portion that is helically disposed on the shaft, wherein the diameter of the shaft is at least half of the diameter of the hollow auger. A used herein, a flight is a rotating helical screw blade, to move solid, liquid or granular materials. Preferably the flight is helicoid. The hollow auger may have a diameter between 40 and 60 millimeter. The shaft may have a diameter of about 20 millimeter and the hollow auger may have a diameter of about 40 millimeter. The shaft extends in the longitudinal direction over a length of at least 60 centimeter, in particular at least 70 centimeter, at least 80 centimeter, at least 90 centimeter or at least 100 centimeter and the flight extends in the longitudinal direction over a length of at least 50 centimeter, at least 60 centimeter, at least 70 centimeter, at least 80 centimeter, or at least 90 centimeter. In one embodiment, the compressed air is discharged at a drilling depth of about 60-100 cm, in particular about 60-90cm, more in particular about 70- 90cm, even more in particular about 80-90cm. Advantageously, the design of the hollow auger (the ratio between the shaft / the flight should be not smaller than 1, but not larger than 2) allows having a strong structure to penetrate to a depth of about 60-100 cm in (highly compacted) subsoils, in particular at least 60, 70, 80, or 90cm, using conventional hydraulic systems.

In a first aspect, which can occur in combination with the other aspects and embodiments of the invention which are described herein, the present invention relates to method as described above, further comprising the step of discharging fluid nutrient into the surrounding medium via the at least one laterally directed outlet opening while discharging compressed air. In preferred embodiments, the compressed air and the fluid nutrient are discharged via the same opening or the same openings of the at least one laterally directed outlet opening. The fluid nutrient may preferably be in a liquid-like form. In an embodiment, the nutrient is at least one of the group consisting of carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), sulfur (S), calcium (Ca), magnesium (Mg), iron (Fe), boron (B), manganese (Mn), copper (Cu) and zinc (Zn). Alternatively or on combination with the first aspect, the present invention relates to method as described above, further comprising the step of discharging microorganisms (e.g. bacteria), mycorrizha and chemical compounds into the surrounding medium via the at least one laterally directed outlet opening while discharging compressed air. The microorganisms (e.g. bacteria), mycorrizha and chemical compounds may preferably be in a liquid-like form.

In a second aspect, which can occur in combination with the other aspects and embodiments of the invention which are described herein, the present invention relates to method as described above, wherein the compressed air is continuously or intermittently discharged while simultaneously lowering and rotating the drilling tool. In an embodiment, the compressed air is continuously or intermittently discharged over a drilling depth between 20 and 200 centimeter (cm), preferably about 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190 or 200 centimeter, in particular the compressed air is continuously or intermittently discharged over a drilling depth of at least 50 cm, 55 cm, 60 cm, 65 cm, 70 cm, 75 cm, 80 cm, 85 cm, 90 cm or 100 cm. In another embodiment, the drilling tool is rotated in the rotational direction with a speed between 50 and 500 rpm, preferably about 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490 or 500 rpm. Advantageously, higher speeds are better for lowering vertical displacement forces while drilling.

In a third aspect, which can occur in combination with the other aspects and embodiments of the invention which are described herein, the present invention relates to method as described above, wherein the discharge rate of the compressed air is controlled as a function of either the drilling depth, soil conditions or the rotational speed of the drilling tool. Advantageously, the amount of injected air may be changed according to the size of available compressor, thereby allowing the optimal use of compressor. For example, if the soil is moist and loose, the discharge of compressed air may be either done intermittently or lowered but continuous.

Furthermore, the present invention relates to a rotary drilling system. Said rotary drilling system comprising a drilling tool with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool; means for rotating the drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to the inlet connection. Said rotary drilling system being configured to discharge compressed air into a surrounding medium via the at least one laterally directed outlet opening while simultaneously lowering and rotating the drilling tool.

In an embodiment, at least two laterally directed outlet openings are provided rotational symmetric with respect to the longitudinal axis of the drilling tool. Preferably two, three, four, five, six, seven, eight, nine, ten, eleven or twelve laterally directed outlet openings are provided rotational symmetric with respect to the longitudinal axis of the drilling tool. For example, in case of two, the outlet openings are positioned diametrically opposite to each other. Advantageously, the symmetric arrangement provides for a more stable drilling tool by balancing out the forces on the drilling tool due to discharge compressed air from the drilling tool.

Moreover, the present invention relates to an automatically, mechanically or manually controlled, vehicle, such as a self-propelled vehicle, autonomous vehicle or trailer arrangement for such a self-propelled vehicle, comprising a rotary drilling system. Said rotary drilling system comprising at least one drilling tool, preferably multiple drilling tools, with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening, preferably two diametrically provided outlet openings, and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool; means for rotating each drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to each inlet connection. Said rotary drilling system being configured simultaneously discharge compressed air into a surrounding medium via the laterally directed outlet opening(s) while simultaneously lowering and rotating the at least three drilling tools.

In an embodiment, the drilling tools are spaced apart in an rectangular array, e.g. aligned in a row transverse to the movement direction of the vehicle. Advantageously, drilling of holes in the proposed solution may happen automatically and does not require any human intervention in the process.

In other embodiments, multiple autonomous vehicles as described above are provided near each other and are configured to communicate with one another. As such, once deployed on the field they are able to efficiently share the workload.

In some embodiments, the drilling tool is a hollow auger which preferably extends in the longitudinal direction over a length between 50 and 150 centimeter, preferably about 50, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150 centimeter and/or has a diameter between 10 and 70 millimeter, in particular between 20 and 60 millimeter, preferably about 10, 20, 30, 40, 50, 60 or 70 millimeter.

Brief description of Drawings

The invention will be explained in more detail below with reference to drawings in which illustrative embodiments thereof are shown. They are intended exclusively for illustrative purposes and not to restrict the inventive concept, which is defined by the appended claims.

Figure 1 shows in a perspective view a trailer according to an embodiment of the invention;

Figure 2 shows a cross-sectional view of the trailer shown in Figure 1; and

Figure 3 shows a detail of the drilling station shown in Figure 2;

Figure 4 shows a graph of soil treatment on maize yields.

Detailed Description of Embodiments

The present disclosure will be described with respect to particular embodiments and with reference to certain drawings but the disclosure is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not necessarily correspond to actual reductions to practice of the disclosure.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. The terms are interchangeable under appropriate circumstances and the embodiments of the disclosure can operate in other sequences than described or illustrated herein.

Moreover, the terms top, bottom, back, front and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. The terms so used are interchangeable under appropriate circumstances and the embodiments of the invention described herein can operate in other orientations than described or illustrated herein.

Furthermore, the various embodiments, although referred to as “preferred” are to be construed as exemplary manners in which the disclosure may be implemented rather than as limiting the scope of the disclosure. The term “comprising”, used in the claims, should not be interpreted as being restricted to the elements or steps listed thereafter; it does not exclude other elements or steps. It needs to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression “a device comprising A and B” should not be limited to devices consisting only of components A and B, rather with respect to the present disclosure, the only enumerated components of the device are A and B, and further the claim should be interpreted as including equivalents of those components.

Different aspects of the present disclosure will be described more fully hereinafter with reference to the enclosed drawings. The embodiments disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein.

Figures 1 to 3 show a trailer 1, or parts thereof, that may be driven by tractor over a field. Alternatively, instead of a trailer, a self-propelled vehicle may be provided. The overall dimensions of the trailer 1 meet the European road requirements directive 96/5 3ZEC, for example 5,5m long and 2,5m wide. The trailer has swivel wheels in the front and fixed wheels on the back. It has a swivel link of Im long that can be put down or up in the front. This link is put in down position and connects with the towing pin of the tractor while being towed by the tractor. During transport or in storage condition, it can be put in up position to save space.

The trailer 1 comprises a rotary drilling system 3 having a number of equally- spaced drilling stations 32, a trailer frame 2 provided with a platform 31 of the rotary drilling system 3 and an air compressor 4 connected with each of the drilling stations 32. The platform 31 may be configured movable along the longitudinal direction of the trailer frame 2. In said case, the frame 2 may be provided with guides and racks along two long sides to move the moveable platform to any desired longitudinal position within the trailer. Alternatively, the platform may be statically connected to the frame with multiple rows of drilling stations for faster hole making.

Each drilling station 32 (shown in figure 3) may be independently controlled and comprises a drilling augur 321, a mechanism 325 to move the augur up and down and a mechanism 324 to rotate the augur at a desired speed either in clockwise or in anti- clockwise directions. Hydraulic actuators may be used as mechanisms to rotate the augurs and moving the augurs up and down. Electric actuators can also be used instead. The position of the drilling augur can be locked, for example electronically, at a position suitable for transportation and storage.

For each drilling station, the rotary drilling system 3 comprises guides 328 and racks 327 to move the auger vertically up or down. The drilling station moves up and down along two C channel guides 328 and is driven through a pinion on a rack fixed to the platform. The pinion is connected to the vertical mechanism 325 through a worm gearbox 326. The rotary mechanism 324 is connected to the drilling tool 321 through a rotary union 323.

The drilling augers 321 are hollow and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling auger. The drilling augers 321 are provided with an internal compressed air passage extending between an inlet connection fluidly connected to the compressor 4 via the rotary union 323 and diametrically positioned, laterally directed outlet openings 322 provided near the drilling end of the auger 321. It can have a flange connection or any other connection on one side so as to be able to be mechanically connected to the rotary union 323. The rotary union transfers the rotary action of the rotary actuator 324 to the auger while conveying the compressed air flow from the compressor 4 into the rotating auger. For example, the rotary union may have two concentric elements. The inner element rotates with the rotary actuator 324 and the outer element is fixed to the support platform 31. Air flows from the outer element into the inner element and then through the auger.

In this way means are provided to supply compressed air through the rotating augur into the soil. The air compressor 4 needed for this may be mounted on a stand with wheels of its own. This stand can be mechanically connected to the trolley at one end. Solenoid valves are provided to either turn on or off the air flow to the drilling augurs.

Figure 4 shows a graph of experimental results. A field experiment was performed according to the following procedure.

Total size of the field was 2 ha. Treatments include grid pattern of drilling vertical holes at various depth and spacing using an automated drilling machine operated by hydraulic power of a tractor. Thirteen treatments were arranged in completely randomized design (CRD) with three replications. Each treatment plot size was 10.0x9.0 m2. Treatments include T7 (50cm depth, 50cm space), T8 (50cm depth, 75cm space), T9 (50cm depth, 100cm space), T10 (90cm depth, 50cm space), Ti l (90cm depth, 75cm space), T12 (90cm depth, 100cm space), control (without holes). Treatments were applied one week before seeding of the maize crop Zea mays. Before treatment application, soil samples were collected to measure the initial soil physical and chemical properties. In the field, water infiltration rate and soil penetration resistance test were also carried out. Moreover, samples for soil bulk density at 40cm and 70cm depths were collected. For soil chemical properties, samples were collected at 30cm, 60cm and 90cm before treatment application. During the cropping season Normalized Difference Vegetation Index (ND VI; a tool used to monitor crop health and growth) and crop height data was recorded over the applied treatment plots using proximal crop senor CropCircle at the crop maturity stage. Finally the yield (fresh Biomass) was measured using GPS based combine harvester equipped with yield measurement sensors on it. Analysis of variance was calculated and treatment means were compared following the Tukey’s LSD test.

As compared to control, maize yield was increased in T10, T11 and T12 by 5.25%, 12.9% and 11.48%, respectively. Whereas, yield was decreased in T7, T8 and T9 by 1.78%, 5,09% and 4.65% respectively. These results show that soil aeration according to the method of the present invention at a depth of more than 50 cm (e.g., as deep as 90 cm) ameliorates the soil and results in higher crop yields.

Other alternatives and equivalent embodiments of the present invention are conceivable within the idea of the invention, as will be clear to the person skilled in the art. The scope of the invention is limited only by the appended claims.

List of reference signs

1. Trailer

2. Frame

3. Rotary drilling system

4. Compressor

31. Support Platform

32. Drilling Station

321. Auger

322. Outlet Openings

323. Rotary Union

324. Rotary Actuator

325. Vertical Actuator

326. Worm Gearbox

327. Rack

328. C-guide

Claims

1. Method for physical soil amelioration using a rotary drilling system comprising: a drilling tool with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool; means for rotating the drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to the inlet connection, said method comprising the step of discharging compressed air into a surrounding medium via the at least one laterally directed outlet opening while simultaneously lowering and rotating the drilling tool, wherein the drilling tool comprises a hollow auger having a shaft and a flight that extends radially away from the shaft, wherein the flight comprising a helical portion that is helically disposed on the shaft, wherein the diameter of the shaft is at least half of the diameter of the hollow auger, and wherein the shaft extends in the longitudinal direction over a length of at least 60 centimeter and the flight extends in the longitudinal direction over a length of at least 30 centimeter, wherein the compressed air is discharged at a drilling depth of about 60 to 100 cm.

2. Method according to claim 1, wherein the hollow auger has a diameter between 10 and 70 millimeter.

3. Method according to claim 1, wherein the shaft has a diameter of about 20 millimeter and the hollow auger has a diameter of about 40 millimeter.

2. Method according to claim 1, comprising the step of discharging fluid nutrient into the surrounding medium via the at least one laterally directed outlet opening while discharging compressed air.

3. Method according to claim 2, wherein the nutrient comprises of at least one of the group consisting of carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, iron, boron, manganese, copper and zinc.

4. Method according to claim 2 or claim 3, wherein the compressed air and the fluid nutrients are discharged via the same opening(s) of the at least one laterally directed outlet opening.

5. Method according to any one of the preceding claims, wherein the compressed air is continuously discharged while simultaneously lowering and rotating the drilling tool.

6. Method according to any one of the preceding claims, wherein the compressed air is intermittently discharged while simultaneously lowering and rotating the drilling tool.

7. Method according to claim 5 or claim 6, wherein the compressed air is continuously or intermittently discharged over a drilling depth between 20 and 200 cm, preferably between 50 and 100 cm.

8. Method according to any one of the preceding claims, wherein the drilling tool is rotated in the rotational direction with a speed between 50 and 500 rpm.

9. Drilling tool with a compressed air passage extending between an inlet connection and at least one laterally directed outlet opening and configured for drilling responsive to rotation in a rotational direction about the longitudinal axis of the drilling tool.

10. Drilling tool according to claim 9, wherein the drilling tool comprises at least one laterally directed outlet opening, preferably two laterally directed outlet openings provided diametrically opposite to each other.

11. Drilling tool according to claim 10, wherein the drilling tool extends in the longitudinal direction over a length ranging from 50 to 150 cm, preferably about 80 cm

12. Rotary drilling system comprising: a drilling tool according to any one of claims 9-11; means for rotating the drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to the inlet connection, said rotary drilling system being configured to discharge compressed air into a surrounding medium via the at least one laterally directed outlet opening while simultaneously lowering and rotating the drilling tool.

13. Vehicle, such as a self-propelled vehicle or a trailer therefor, having a rotary drilling system comprising: at least one drilling tool according to any one of claims 8-11; means for rotating each drilling tool in the rotational direction about the longitudinal axis of the drilling tool; and means for supplying compressed air to each inlet connection, said rotary drilling system being configured to simultaneously discharge compressed air into a surrounding medium via the at least three laterally directed outlet openings while simultaneously lowering and rotating the at least three drilling tools.

14. Vehicle according to claim 13, wherein at least two drilling tools are provided and spaced apart in a rectangular array.

15. Vehicle according to claim 14, wherein at least three drilling tools are provided and spaced apart in two rows transverse to the movement direction of the vehicle.