Field of the invention

The present invention in general relates to improvement in the field of agriculture.

More specifically, the present invention in a first aspect relates to a system for soil loosening of soil which has been compacted by wheels of an agricultural vehicle or an agricultural implement.

In a second aspect the present invention relates to an agricultural vehicle comprising such a system.

In a third aspect the present invention relates to an agricultural implement comprising a system according to the first aspect of the invention.

In a fourth aspect the present invention relates to the use of a system of the first aspect of the present invention or of an agricultural vehicle according to the second aspect of the present invention, or of an agricultural implement according to the third aspect of the invention for avoiding uneven crop growth between crops being or to be sown in and outside a wheel track, respectively.

Background of the invention

In order to prepare an agricultural field for sowing crop seeds a number of conditioning steps need to be performed so that optimum crop growth can be assured. These steps involve inter alia ploughing, and other types of seedbed preparations.

Such conditioning steps performed prior to the step of sowing the seeds, and the sowing operation itself are usually performed with the help of an implement configured to perform the intended purpose and these implements are usually being towed or carried by an agricultural vehicle, such as a tractor.

Upon driving a tractor on an agricultural field the areas of soil which have been subjected to the weight of the wheels, especially the rear wheels of the tractor will encounter a not insignificant degree of compaction in the soil.

If soil is being too compact an optimum growth of seeds may be prevented. In order to alleviate this problem it is customary in harrowing and in sowing operations to provide for loosening the soil which has been just driven over by wheels of an agricultural vehicle or implement.

Accordingly, in prior art systems a soil loosening implement is provided behind the tractor. Such an implement comprises in respect of each rear wheel a group of tines or the like which are configured to interact with the soil in the specific wheel track so as to loosening the soil of the track which has just been compacted by being overdriven by that wheel.

Each group of tines may be adjusted with respect to working depth. However, once set for a specific working depth, each group of tines is fixed, and the working depth cannot be altered dynamically during operation of the vehicle.

CN 105850238 A discloses a system for loosening soil in an agricultural field. The system comprises a frame having a support wheel. The frame is configured for being towed behind a tractor. The frame comprises a number of soil loosening devices. Each soil loosening device comprises a soil loosening element, the working depth of which may be adjusted by means of an adjustment means. In respect of each soil loosening device a sensor senses the distance to the ground from that sensor in the area of the soil loosening element. A control unit receives signals from the sensors relating to the sensed distance and on the basis of this, a feedback signal is being send from the control unit to the adjustment means. Hereby the working depth of the soil loosening element is adjusted based on the sensed distance to the ground. CN 105850238 A does not disclose that a height distance between soil which has been compacted by wheels and soil which has not been compacted is being determined and that the degree of soil loosening in a wheel track is adjusted on the basis of such determination.

In order to provide optimum growth of crops it is important that each crop seed to be sown is provided with equal growth condition. Especially, in the early stages of growth the crop seedlings will encounter a competition with neighboring seedlings in relation to access of a sufficient amount of water, sunlight and nutrients. Once a specific crop seedling has lost this competition caused by stronger growth of the neighboring seedlings, that specific crop seedling is likely not to be able to overcome this early growth suppression. The result will be that seedlings growing in soil which has been subjected to compaction by a wheel of an agricultural implement will encounter non-optimum growth conditions compared to seedlings growing in neighboring soil which has not encountered this type of compaction. Even though the prior art soil loosening systems provide for soil loosening in wheel tracks which have encountered soil compaction, the prior art soil loosening systems suffer from certain disadvantages.

One of these disadvantages of the prior art soil loosening systems is that in case the field to be worked comprises different types of soil it will happen that different degrees of soil compaction results when the tractor's wheels drive the soil. For this reason these different types of soil need different degrees of soil loosening in order to obtain an even soil compaction in the field. In case no differentiation is made as to degree of soil loosening in respect of different types of soil, the result is that soil compaction varies in different areas of the field. Such variations in soil compaction throughout the field imply different growth conditions for the crop seeds.

The same variations may result in case the speed of the tractor working the field varies; a relative slow speed is expected to result in a relative high degree of soil compaction, whereas a relative high speed is expected to result in a relative low degree of soil compaction.

Degree of tire pressure and choice of type of tire will also affect the degree of soil compaction. A non-optimum choice of type of tire and/or tire pressure will lead to excessive soil compaction.

Furthermore, variations in degree of soil compaction will be encountered when an agricultural vehicle or implement substantially alters its weight during work, such as during a sowing operation or a fertilizing operation or a harvesting operation.

Accordingly, there exists a need for an improved track loosening system which to a higher degree will ensure a more homogeneous soil compaction of a field to be harrowed or sown by crop seed.

It is an objective of the present invention to provide systems, vehicles, implements and uses which meet this need.

Brief description of the invention

This objective is fulfilled with the present invention in its various aspects.

Accordingly, the present invention in its first aspect relates to a system for soil loosening of soil which has become compacted by wheels of an agricultural vehicle or an agricultural implement, said system comprises: -one or more soil loosening devices for loosening soil in a wheel track;

-in respect of each soil loosening device, a sensing system; -a control unit; wherein each of said one or more soil loosening devices comprises one or more soil loosening elements for loosening soil is said wheel track, and wherein each of said one or more soil loosening elements is/are mechanically connected to adjustment means for adjusting the degree of soil loosening provided by said one or more soil loosening elements; characterized in that in respect of each soil loosening device, said sensing system is configured for sensing a height difference between soil located in said wheel track and soil located outside said wheel track; wherein said sensing system being configured to provide one or more sensing signals representative of said sensed height difference of soil; and wherein said control unit is configured to receive said one or more sensing signals provided by said sensing system and to provide a control signal on the basis thereof; wherein said adjustment means is configured to receive said control signal, and on the basis thereof to adjust the degree of soil loosening of said one or more soil loosening elements of said one or more soil loosening devices.

The present invention relates in a second aspect to an agricultural vehicle comprising a system according to the first aspect. In a third aspect the present invention relates to an agricultural implement comprising a system according to the first aspect of the present invention.

In a fourth aspect the present invention relates to the use of a soil loosening system according to the first aspect of the present invention, or of an agricultural vehicle according to according to the second aspect of the present invention, or of an agricultural implement according to the third aspect of the present invention during performance of an agricultural work operation in an agricultural field.

The present invention provides in its various aspects for reducing variance in soil compaction in a field to be sown by crop seeds, thereby avoiding uneven crop growth between crops being or to be sown in and outside a wheel track, respectively. This is due to the ability of the system to provide an even soil compaction of the soil, irrespective of whether the soil has been compacted by wheels or not, thereby also minimizing the potential of erosion of water, erosion of soil caused by the wind and reducing pesticide leaching potential.

Brief description of the figures

Fig. 1 is a side view diagrammatically illustrating the working mode of a prior art soil loosening system for an agricultural vehicle.

Fig. 2 is a side view diagrammatically illustrating the working mode of a soil loosening system for an agricultural vehicle according to the present invention. Fig. 3 shows a diagram illustrating in more detail the various components of a soil loosening system according to the present invention and the mutual interactions between these components.

Fig. 4 is a top view illustrating possible positions of sensors, for use with the system of the invention, in relation to an agricultural implement.

Detailed description of the invention

The first aspect of the present invention

In the first aspect the present invention relates to a system for soil loosening of soil which has become compacted by wheels of an agricultural vehicle or an agricultural implement, said system comprises:

-one or more soil loosening devices for loosening soil in a wheel track;

-in respect of each soil loosening device, a sensing system;

-a control unit; wherein each of said one or more soil loosening devices comprises one or more soil loosening elements for loosening soil is said wheel track, and wherein each of said one or more soil loosening elements is/are mechanically connected to adjustment means for adjusting the degree of soil loosening provided by said one or more soil loosening elements; characterized in that in respect of each soil loosening device, said sensing system is configured for sensing a height difference between soil located in said wheel track and soil located outside said wheel track; wherein said sensing system being configured to provide one or more sensing signals

representative of said sensed height difference of soil; and wherein said control unit is configured to receive said one or more sensing signals provided by said sensing system and to provide a control signal on the basis thereof; wherein said adjustment means is configured to receive said control signal, and on the basis thereof to adjust the degree of soil loosening of said one or more soil loosening elements of said one or more soil loosening devices.

The system according to the first aspect of the present invention is intended to be mounted on an agricultural vehicle or implement. The sensing system of the implement makes it possible to detect a soil compaction of soil imparted by wheels of that vehicle or the implement.

Furthermore, on the basis of the sensed height differences, which are indicative of a soil compaction, the soil loosening device(s) with its soil loosening elements provides for loosening the soil that has been compacted by the wheels. Thereby the soil which has been compacted by the wheels of the vehicle or the implement is brought back to a condition in which the soil compaction is eliminated by the action of the soil loosening elements. With the system of the first aspect of the present invention, the degree of soil loosening may be adjusted to a degree which result in the same degree of compression as the surrounding soil which has not

(immediately) been subjected to the compacting effect of the wheels of the vehicle or implement. This ultimately provides for a more even soil quality and hence an improved crop yield.

In the present description and in the appended claims the term "agricultural vehicle" shall be construed to mean a vehicle that is self-propelled.

In the present description and in the appended claims the term "agricultural implement" shall be construed to mean an implement which is not self-propelled.

In the present description and in the appended claims it shall be understood that the one or more soil loosening devices each are responsible for soil loosening of an individual wheel track created by one or more wheels of the vehicle or implement, such as a wheel track created by a carrying wheel of an implement or of a front wheel and a rear wheel of a tractor having the same lateral position. By incorporating more soil loosening devices in the system it is thus possible to loose soil which has been compacted by more wheels of a tractor and/or an implement.

It should be noted though, that a common control unit may be used in respect of more than one soil loosening device. It should likewise be noted that a common control unit may be configured for receiving sensing signals from more than one sensing system corresponding to more than one soil loosening device.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises one and only one sensor configured for sensing a height difference between soil located in said wheel track and soil located outside said wheel track. This embodiment provides for a very simple set-up as only sensor is used.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises two or more sensors, wherein one sensor is configured for sensing a height of soil located in said wheel track, and wherein an additional and optionally more sensors are configured for sensing a height of soil located outside said wheel track. Hereby is ensured a more accurate determination of a height difference between soil located in a wheel track and soil located outside that wheel track.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises a sensor which is configured for sensing a height of soil located in said wheel track before that soil is being subjected to soil loosening. This embodiment allows a direct determination of soil compaction in that wheel track because the height of soil in that wheel track is measured before any soil loosening is performed.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises a sensor which is configured for sensing a height of soil located in said wheel track after that soil is being subjected to soil loosening. This embodiment allows a direct determination of the degree of soil loosening in the wheel track because the height of soil in that wheel track is measured after the soil loosening is performed.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises a sensor which is configured for sensing a height of soil located in said wheel track before that soil is being subjected to soil loosening; and wherein said sensing system furthermore comprises a sensor which is configured for sensing a height of soil located in said wheel track after that soil is being subjected to soil loosening.

Hereby improved sensing is achieved. The one sensor may sense the degree of soil compaction immediately after the wheel track has been formed. On the basis of the measured height of the soil in this wheel track the control unit may send its feedback to the adjustment means. As a control the sensed height of soil located in said wheel track after that soil is being subjected to soil loosening is used. And on the basis of this sensed height an adjustment control signal may be sent to the adjustment means.

In one embodiment of the system of the first aspect of the present invention the number of soil loosening devices is 1 - 10, and being configured for soil loosening in a single or more wheel tracks, such as in the wheel tracks of one or both of the two rear wheels of an agricultural vehicle; or for soil loosening in the wheel tracks of four wheels of an agricultural vehicle; and/or for soil loosening in one or more wheel tracks of an agricultural implement being towed by an agricultural vehicle. More soil loosening devices provides for being able to perform soil loosening in respect of more wheels on the vehicle and/or implement.

In one embodiment of the system of the first aspect of the present invention said soil loosening elements independently being tines or coulter blades.

These types of soil loosening elements provides for efficient soil loosening. In one embodiment of the system of the first aspect of the present invention said and in respect of one or more of said soil loosening devices, the working width of said corresponding soil loosening elements independently being 20 - 200 cm, such as 30 - 180 cm, for example 40 - 170 cm, e.g. 50 - 160 cm, such as 60 - 150 cm, for example 70 - 140 cm, e.g. 80 - 130 cm, such as 90 - 120 cm or 100 - 110 cm. Such working widths allow efficient soil loosening even in respect of the widest wheels used for agricultural implements and vehicles.

In one embodiment of the system of the first aspect of the present invention and in respect of one or more soil loosening devices, said adjustment means independently are configured to adjust the degree of soil loosening by altering the working depth of said one or more soil loosening elements; and/or by altering the angle of attack of said one or more soil loosening elements; and/or by altering a speed of movement of said one or more soil loosening elements, in a case said soil loosening provided by said one or more soil loosening elements is provided by mechanically driven soil loosening elements; and/or by movement of said one or more soil loosening elements by means of parallelogrammic suspension means.

These types and directions of movements of the soil loosening elements provide for efficient soil loosening.

In one embodiment of the system of the first aspect of the present invention said control unit is configured for providing said control signal to said adjustment means of said one or more soil loosening devices on the basis of said one or more sensing signals in accordance with a predetermined algorithm. Defining a predetermined algorithm allow for efficient control of the soil loosening system, thereby optimizing the quality of soil loosening.

In one embodiment of the system of the first aspect of the present invention said predetermined algorithm is configured in such a way that said control unit is configured to provide a control signal to said adjustment means so as to increase the degree of soil loosening of said one or more soil loosening devices in case said sensing system is sensing a higher soil height at a location outside a wheel track compared to the soil height of soil loosened soil at a location in said wheel track.

In one embodiment of the system of the first aspect of the present invention said predetermined algorithm is configured in such a way that said control unit is configured to provide a control signal to said adjustment means so as to decrease the degree of soil loosening of said one or more soil loosening devices in case said sensing system is sensing a higher soil height of soil loosened soil at a location in said wheel track, compared to the soil height at a location outside said wheel track.

Such an algorithm provides for efficient soil loosening. In one embodiment of the system of the first aspect of the present invention said predetermined algorithm is configured in such a way that said control unit is configured to provide a control signal to said adjustment means on the basis of a sensed height of soil plus/minus a

predetermined offset value.

Incorporating an offset value makes it possible to aim at a soil loosening, in which the height of soil which has been loosened is higher than the soil outside the wheel track. This is an advantage as soil loosened soil typically will be less compact immediately after soil loosening, compared to the surrounding soil outside the wheel track and also compared to the degree of compaction of soil in said wheel tract after some time has passed.

In one embodiment of the system of the first aspect of the present invention said adjustment means of said one or more soil loosening devices independently comprises one or more hydraulic actuators, one or more pneumatic actuators, or one or more electric actuators for adjustment of said degree of soil loosening.

These types of actuators provides for efficient and fast regulation of the degree of soil loosening of the soil loosening elements of the adjustment means.

In one embodiment of the system of the first aspect of the present invention and in respect of one or more of said soil loosening devices, said soil loosening device comprises two or more soil loosening elements which are configured to move in concert.

Hereby is achieved soil loosening in a wider width compared to the situation in which only one soil loosening element is used per soil loosening device.

In one embodiment of the system of the first aspect of the present invention said and in respect of one or more of said soil loosening devices, said one or more soil loosening elements independently are configured for being moved by said adjustment means by rotation around a rotational axis, such as an essentially horizontal rotational axis.

In one embodiment of the system of the first aspect of the present invention and in respect of one or more of said soil loosening devices, said one or more soil loosening elements independently are configured for being moved by said adjustment means by movement in an essential vertical direction.

In one embodiment of the system of the first aspect of the present invention said and in respect of one or more of said soil loosening devices, said one or more soil loosening elements are suspended in a parallelogrammic suspension, thereby allowing said soil loosening elements to be moved by said adjustment means by movement in a direction having a vertical component and a horizontal component.

These three different ways of adjusting the degree of soil loosening provides for efficient soil loosening. In one embodiment of the system of the first aspect of the present invention and in respect of one or more of said soil loosing devices said sensing system is configured for providing said one or more sensing signals via mechanical sensing means.

In one embodiment of the system of the first aspect of the present invention said sensing system is comprising a sensing wheel which is pivotally suspended and configured to follow the surface of soil in said wheel track, and also comprising one or more additionally sensing wheels which is/are pivotally suspended and configured to follow the surface of soil located outside said wheel track; wherein the height difference between soil loosened soil located in said wheel track and soil located outside said wheel track is determined on the basis of the respective sensed heights of said two or more sensing wheels.

Hereby is ensured, in a simple and reliable way, the sensing of the height of soil.

In one embodiment of the system of the first aspect of the present invention and in respect of one or more of said soil loosing devices said sensing system is configured for providing said one or more sensing signals via non-mechanical sensing means. In one embodiment of the system of the first aspect of the present invention said sensing system comprising one or more transmitters configured to transmit an electromagnetic radiation; and comprising one or more receivers which is/are configured to receive a reflected signal of said transmitted electromagnetic radiation; and wherein the height difference between soil located in said wheel track and soil located outside said wheel track is determined on the basis of detection of time-of-flight, frequency, wavelength, intensity/amplitude of the electromagnetic radiation involved, or a combination thereof.

In one embodiment of the system of the first aspect of the present invention said non-mechanical sensing system comprises a laser sensing system, an infrared sensing system or a laser range scanning sensing system. In one embodiment of the system of the first aspect of the present invention and in respect of one or more of said soil loosing devices said sensing system is configured for providing said one or more sensing signals via sonic sensing means.

In one embodiment of the system of the first aspect of the present invention said sensing system comprising one or more transmitters configured to transmit a sonic radiation; and comprising one or more receivers which is/are configured to receive a reflected sonic signal of said transmitted sonic radiation; and wherein the height difference between soil located in said wheel track and soil located outside said wheel track is determined on the basis of detection of time -of- flight, frequency, wavelength, intensity/am litude of the sonic radiation involved, or a combination thereof.

These non-mechanical sensing means provides sensing mechanisms which are less prone to mechanical wear and tear.

In one embodiment of the system of the first aspect of the present invention said control unit is configured in such a way that both in respect of soil in said wheel track and in respect of soil outside said wheel track, a number of measurement samples of soil heights are made; and wherein said control unit is configured for subsequently averaging these samples of soil heights in said wheel track on the one hand and also for averaging these samples of soil heights outside said wheel track on the other hand, and wherein said control signal is based on the difference of said averaged samples of soil heights.

In one embodiment of the system of the first aspect of the present invention said control unit is configured in such a way that the measurement samples of soil heights independently is performed at a sampling rate of 1 - 200 Hz; such as 5 - 150 Hz, for example 10 - 100 Hz, such as 25 - 80 Hz, e.g. 30 - 60 Hz; and/or wherein said control unit is configured in such a way that said control signal independently is provided at a rate of 0.1 - 10 Hz, such as 0.5 - 9 Hz, e.g. 1 - 8 Hz, such as 2 - 7 Hz, e.g. 3 - 6 Hz or 4 - 5 Hz.

Control of the soil loosening system according to averaging procedures provides for efficient sensing and feedback and thus for efficient soil loosening of the soil loosening system.

In one embodiment of the system of the first aspect of the present invention said control unit is configured to perform a filtering, such as a low-pass filtering, of the sensed heights or height differences prior to providing said control signal.

Filtration provides for better and more accurate description of the soil surfaces, and finally an improved soil loosening operation.

In one embodiment of the system of the first aspect of the present invention said control unit is configured to provide said control signal by means of a P (Proportional) control, PID

(Proportional Integration Differentiation) control, three positon control, or a step control.

These ways of providing feedback provides for efficient soil loosening of the soil loosening system. In one embodiment of the system of the first aspect of the present invention said one or more of said sensors configured for sensing a height of soil located outside a wheel track independent is/are configured for being arranged, in relation to the direction of movement, in front of said wheel, and/or in a lateral position in relation to said wheel and/or behind said wheel; or a combination thereof.

These locations are suitable locations for arranging some of the sensors.

In one embodiment of the system of the first aspect of the present invention said system further comprising one or more mounting brackets configured for carrying one or more of said soil loosening devices, or parts thereof, and for being mounted on an agricultural vehicle or implement.

In one embodiment of the system of the first aspect of the present invention said system further comprising one or more mounting brackets configured for carrying said sensing system, or parts thereof, and for being mounted on an agricultural vehicle or implement.

In one embodiment of these embodiments of the present invention said mounting bracket configured for carrying one or more of said soil loosening devices and said mounting bracket configured for carrying said sensing system are the same bracket or are different brackets.

Providing the system with brackets provides for easy mounting on a vehicle or implement and further provides for easy adjustment.

In one embodiment of the system of the first aspect of the present invention said system further comprising a monitor and/or input means; wherein said monitor is configured for being coupled to said control unit so as to display to a user the settings and/or information relating to the operation of said system; and wherein said input means, e.g. in a form of a keyboard, is configured for being coupled to said control unit so as enable setting up and/or calibration of said system; said monitor and/or said input means optionally being in the form of an HMI (Human- Machine Interface) or a GUI (Graphical User Interface) .

Such means provides for easy control of the soil loosening system and monitoring of the operation thereof.

In one embodiment of the system of the first aspect of the present invention said system further comprises a GNSS (Global Navigation Satellite System) receiver for providing information of the location on the field of said agricultural vehicle or said agricultural implement. In a particular embodiment said control unit is configured to receive information from said GNSS receiver and also is being configured to have stored therein, data relating to characteristics of the soil at different locations of a field.

Such embodiments enables varying the degree of soil loosening, depending on the different types of soil in various areas of the field, such as sandy areas, muddy areas, areas of clay soil.

In one embodiment of the system of the first aspect of the present invention said sensing system comprises one or more force transducers which are configured for sensing a horizontally oriented force of one or more of said soil loosening elements, such as a strain gauge; or in the form of one or more sensors for sensing a hydraulic pressure in a hydraulic actuator which is configured for suspending one or more of said one or more soil loosening elements.

This provides for a simple way of providing the sensing system of the system of the invention.

In one embodiment of the system of the first aspect of the present invention said system furthermore comprises one or more axle or wheel load sensors for sensing the load on one or more axles or wheels of said agricultural vehicle or agricultural implement; wherein said control unit is configured for receiving a load sensing signal from said one or more axle or wheel load sensors; and wherein said control unit is configured for providing said control signal to said adjustment means in a way wherein said control signal is depending on the load as sensed by said one or more load sensors, thereby allowing the severity of the soil loosening provided by said soil loosening devices to be dependent of the axle or wheel load of said agricultural vehicle or said agricultural implement.

Hereby is attained that in a situation where the axle load during field work is not constant, for example during harvesting or spreading operations, the severity of the soil loosening is made depending on the load of the wheels or axle of the agricultural vehicle or implement.

Thereby an even better soil loosening quality be obtained.

This embodiment is especially preferably in a case where the control unit is configured to provide a control signal to the adjustment means on the basis of a sensed height of soil plus/minus a predetermined offset value. In general the system according to the first aspect of the present invention in all its embodiments is preferably configured for automatic operation. Thereby soil loosening to a desired extent may automatically be achieved.

The second aspect of the present invention

In a second aspect the present invention relates to an agricultural vehicle comprising a system according to the first aspect.

The third aspect of the present invention In a third aspect the present invention relates to an agricultural implement comprising a system according to the first aspect of the present invention.

In one embodiment of the implement of the third aspect of the present invention said implement is a tilling implement, such as a harrowing implement or a sowing implement for sowing crop seeds. In one embodiment of the implement of the third aspect of the present invention said implement is a sowing implement, and wherein said sensing system comprises two or more sensors wherein one or more of said two or more sensors are configured to sense the working depth of one or more coulters on a sowing machine submerged in soil located in said wheel track; and wherein one or more of said two or more sensors are configured to sense the working depth of one or more coulters on a sowing machine submerged in soil located outside said wheel track.

This embodiment utilized mechanics already in existence on a sowing machine for providing sensing signals.

In one embodiment said implement said implement is a sowing implement, and wherein said sensing system comprises two or more sensors wherein one or more of said two or more sensors are configured to sense the depth of one or more seed drills on said sowing implement submerged in soil located in said wheel track; and wherein one or more of said two or more sensors are configured to sense the working depth of one or more seed drills on said sowing implement submerged in soil located outside said wheel track. The fourth aspect of the present invention

In a fourth aspect the present invention relates to the use of a soil loosening system according to the first aspect of the present invention, or of an agricultural vehicle according to according to the second aspect of the present invention, or of an agricultural implement according to the third aspect of the present invention during performance of an agricultural work operation in an agricultural field.

In one embodiment of the use of the fourth aspect of the present invention said use is for reducing uneven crop growth between crops being or to be sown in and outside a wheel track, respectively; for reducing erosion and/or for reducing dilution of pesticides. Hereby improved crop yield may be obtained.

Referring now to the drawings for further illustration of the invention in its various aspects, Fig. 1 is a side view which diagrammatically illustrates the working mode of a prior art soil loosening system for an agricultural vehicle.

Fig. 1 shows an agricultural vehicle 200 in the form of a tractor which comprises the rear wheel 4. The tractor is moving in the direction of the movement as indicated by the arrow V.

Behind the tractor a soil loosening system is mounted on mounting bracket 450. The mounting bracket comprises a soil loosening element 422 which is pivotally suspended in on the bracket 450. A spring 402 having a predetermined spring load is connected between the bracket 450 and the soil loosening element 422. The soil loosening element is arranged in a lateral position which corresponds to the lateral position of the rear wheel 4 of the tractor. For the sake of simplicity only one soil loosening element is depicted in Fig. 1. In a real agricultural operation, more soil loosening elements 422 arranged next to each other will be applied so as to cover essentially the full width of each rear wheel 4. As the tractor moves over the soil 2 the rear wheel 4 carrying a huge weight will effect a compaction of the soil 18 thus resulting in compacted soil 13 in the wheel track 12. This is illustrated in Fig. 1 by the lower level of soil at location 13 compared to soil at location 18.

In the soil loosening system of the prior art the soil loosening element 422 will via the spring load be pressed into the soil at position 13 of the wheel track 12, thereby loosening the soil of the wheel track. This is illustrated in fig. 1 by the higher level of soil at location 16 compared to soil of the wheel track 12 at location 13 before its soil loosening.

However, in the prior art soil loosening system there is no possibility for dynamically adjusting the degree of soil loosening in the wheel track while driving over the soil.

Thereby the soil loosening will be determined inter alia by the fixed height of mounting of the bracket 450 carrying the soil loosening element 422, the predetermined spring load of the spring 402 actuating the soil loosening element 422, by the nature of the soil and by the driving speed of the vehicle.

The lack of any dynamic control of the degree of soil loosening in the wheel track 12 ultimately leads to different degree of compaction and thus differences in growth conditions of crops to be grown in soil being present in a wheel track and soil being present outside a wheel track.

Also, a non-optimum choice of tires or tire pressure also result in different degree of soil compaction as does varying weight load of the agricultural vehicle or implement as encountered e.g. during sowing and fertilizing.

These problems are solved by the present invention in its various aspects.

Fig. 2 is a side view diagrammatically illustrating the working mode of a soil loosening system for an agricultural vehicle according to the present invention.

Fig. 2 shows an agricultural vehicle 200 in the form of a tractor which comprises the rear wheel 4. The tractor is moving in the direction of the movement as indicated by the arrow V.

Behind the tractor a soil loosening systemlOO comprising a single soil loosening device 10 is mounted on mounting bracket 50. The mounting bracket comprises a soil loosening element 22 which is pivotally suspended on the bracket 50. An adjustment mean 24 configured to be able to extend and contract is connected to an upper end of the soil loosening element thereby allowing the adjustment the working depth of the soil loosening element 22; as the adjustment mean 24 is extended, the working depth of the soil loosening element 22 is reduced and vice versa. In a real situation the adjustment mean 24 may be supplied with a spring arranged in parallel.

The soil loosening systemlOO in Fig. 2 furthermore comprises a sensing system 14. The sensing system comprises a first sensor 30 arranged behind, in relation to the direction of movement, the soil working element 22. The first sensor 30 is configured for sensing a height of soil in the wheel track 12 at a location 16 after that wheel track 12 has been subjected to soil loosening by said soil loosening element 22.

A second sensor 30' is arranged on a bracket 50' mounted on the vehicle 200 in front of the wheel 4. At this position that sensor 30' is capable at sensing a soil height at a position 18 corresponding to soil which has not been be compacted by the wheel 4.

The sensing system 14 is configured to receive information corresponding to the heights sensed by the sensor 30 and the sensor 30', respectively and on the basis of this information to determine a height difference between the soil and the first sensor 30 at location 16 on the one hand and the soil and the second sensor 30' at location 18 on the other hand. This information is being sent to a control unit 20 which according to a predetermined algorithm is configured to send a control signal 28 to the adjustment means 24. The control signal 28 adjusts the degree of soil loosening performed by said soil loosening element 22 by adjusting the working depth thereof.

This is further illustrated in fig. 3. Fig. 3 shows a diagram illustrating part of the soil loosening system according to the present invention. In Fig. 3 it is seen that the three sensors 30, 30' and 30" are connected to the sensing system 14, which based on the signals received form the sensors 30, 30' and 30" sends a sensing signal 26 to a control unit 20.

Based on the sensing signal 26 received by the control unit 20, the control unit generates a control signal 28 which is being sent to the adjustment means 24 which in turn controls the degree of soil loosening by adjustment of the working depth of the soil loosening element 22 as explained above.

The soil loosening system may also comprise a monitor 52 for monitoring the settings and operation of the system. Furthermore, the control system 100 may comprise input means 54, such as a keyboard for programming and/or calibrating the working mode of the system.

The control unit 20 is usually configured in such a way the control unit 20 provides a control signal 28 to the adjustment means 24 so as to increase the degree of soil loosening of the soil loosening element 22 in case the sensing system by means of e.g. the first sensor 30 and the second sensor 30' is sensing a higher soil height at a location 18 outside a wheel track compared to the soil height at a location 16 of said wheel track after having been subjected to soil loosening. Furthermore, the control unit 20 is usually configured in such a way the control unit 20 provides a control signal 28 to the adjustment means 24 so as to reduce the degree of soil loosening of the soil loosening element 22 in case the sensing system by means of e.g. the first sensor 30 and the second sensor 30' is sensing a lower soil height at a location 18 outside a wheel track compared to the soil height at a location 16 of said wheel track after having been subjected to soil loosening.

Returning to fig. 2 again, the soil loosening element 22 is arranged in a lateral position which corresponds to the lateral position of the rear wheel 4 of the tractor. For the sake of simplicity only one soil loosening element is depicted in Fig. 2. In a real agricultural operation, more soil loosening elements 22 arranged next to each other will be applied so as to cover essentially the full width of the rear wheels.

In use with an agricultural vehicle or an agricultural implement the soil loosening system 100 will comprise two or more soil loosening devices 10, wherein each soil loosening device is responsible of soil loosening in respect of a specific wheel track of said agricultural vehicle and/or implement.

In a case where more than one soil loosening device 10 is used in respect of more than one wheel of an agricultural vehicle or implement, these more than one soil loosening devices 10 may share a common control unit 20, and a common sensing system 14. Alternatively, each soil loosening device may comprise its own dedicated control unit 20, and sensing system 14.

Fig. 4 is a top view illustrating possible positions of sensors, for use with the system of the invention, in relation to an agricultural implement.

Fig. 4 shows a field of soil 2 onto which an agricultural implement 300 is arranged and moving forward in the direction illustrates by the arrow V.

The implement 300 comprises a transverse frame 302 onto which soil working tines 304 are arranged. The frame 302 of the implement 300 is carried by two wheels 4 or gliding shoes. These wheels result in wheel tracks 12, comprising soil 13 and 16.

On the left side of the implement is arranged on a bracket 306 a soil loosening device 10 of the system of the first aspect of the present invention. The soil loosening device comprises a number of soil loosening elements 22 (not visible in Fig. 4). The soil loosening device 10 causes the soil 13 located in the wheel track 12 located immediately behind the wheel 4 to be soil loosened so that the soil loosened soil 16 remains after being subjected to the soil loosening device 10.

In fig. 4 possible positions PI, P2, P3, Ql, Q2 and Q3 of sensors 30,30',30", in relation to the agricultural implement 300 are illustrated.

In case a sensor 30, 30', 30" is positioned so as to sense the height of soil in position PI, the height of soil in the wheel track 12, 13 before the soil is being subjected to any soil loosening can be sensed.

In case a sensor 30, 30', 30" is positioned so as to sense the height of soil in position P2, the height of soil in the wheel track 12, 16 after the soil has been subjected to soil loosening can be sensed.

In case a sensor 30, 30', 30" is positioned so as to sense the height of soil in position Ql, Q2 or Q3, the height of soil 18 located outside a wheel track 12 can be sensed.

In addition to the positions Ql, Q2 and Q3 many other possible positions for sensing the height of soil outside a wheel track 12 is possible.

Fig. 4 only illustrates possible positions PI, P2, Ql, Q2 and Q3 in respect of a single soil loosening device which loses soil compacted by a single wheel 4. However, a similar soil loosening device 10 may be applied as well in respect of the right wheel 4 of the implement 300.

Likewise, the same positions PI , P2, Ql, Q2 and Q3 in relation to wheels of an agricultural vehicle, as illustrated in respect of an agricultural implement, may be used.

It should be understood that all features and achievements discussed above and in the appended claims in relation to one aspect of the present invention and embodiments thereof apply equally well to the other aspects of the present invention and embodiments thereof. List of reference numerals

2 Soil

4 Wheels of an agricultural vehicle or an agricultural implement

10 Soil loosening device 12 Wheel track

13 Soil located in a wheel track before soil loosening

14 Sensing system

16 Soil which has been compacted by a wheel and subsequently loosened by a soil loosening element 18 Soil located outside a wheel track

20 Control unit

22 Soil loosening element

24 Adjustment means

26 Sensing signal 28 Control signal

30,30', 30" Sensor of sensing system

50,50' Mounting bracket

52 Monitor

54 Input means of control system 100 Soil loosening system

200 Agricultural vehicle

300 Agricultural implement

302 Transverse frame of agricultural implement

304 Soil working tine of agricultural implement 306 Bracket of agricultural implement

400 Prior art soil loosening system

402 Spring

422 Soil loosening element of prior art soil loosening system 450 Mounting bracket of prior art soil loosening system

V Direction of movement of vehicle or implement

PI ,P2, Possible position of sensor

Q 1 ,Q2,Q3 Possible position of sensor