GB2500198A

GB2500198A - Soil cultivation system and method

Info

Publication number: GB2500198A
Application number: GB201204334A
Authority: GB
Inventors: David Whattoff
Original assignee: Frontier Agriculture Ltd
Current assignee: Frontier Agriculture Ltd
Priority date: 2012-03-12
Filing date: 2012-03-12
Publication date: 2013-09-18
Anticipated expiration: 2032-03-12
Also published as: GB2500198B; GB201204334D0

Abstract

A soil cultivation system comprises a soil cultivator and a depth control system, wherein the control system is configured to vary the cultivation depth of the soil cultivator in correspondence with a soil characteristic; and a method of soil cultivation with such a system. The soil characteristic maybe soil resistance or electrical conductivity. The soil characteristics at a location within an area of lead maybe a plurality of soil characteristics, each of the plurality of characteristics corresponding to a different soil depth. The control system may comprise a look-up table of values which correspond with a predetermined cultivation depth at a plurality of locations. The predetermined depth at a location may correspond to a historical crop yield at or proximate the location.

Description

1

SOIL CULTIVATION SYSTEM

The present invention relates to soil cultivation equipment, and more particularly, but not exclusively, to tractor-mounted soil cultivation equipment.

5

BACKGROUND

The growth of a plant is sensitive to the characteristics of the soil in which it is rooted, with adverse soil conditions leading to lower yields of agricultural crops. Examples of such 10 adverse soil conditions are compacted layers of soil at or below the exposed surface, and "heavy" soils, such as soils with a generally fine particle size (e.g. less than 2|jm), of which clay is a well-known example. Such fine soils can hold more water (i.e. have a higher water capacity) than coarse soils, such as sand, making them significantly more dense than other soils during wet periods. Compacted soils (e.g. greater than about 2 MPa/300psi) and fine 15 soils can resist the growth of roots, which find it difficult to penetrate through the soil to establish a sufficiently large and deep root network to feed the plant and to reach moisture in deeper soil during dry periods. This can be a particular problem in the case of compacted, dry clay. Similarly, such adverse soils can reduce the flow of water through the soil, retaining water at the surface during wet periods at the surface, and reducing the rise of 20 water from deeper soil during dry periods by impeding the natural capillary action that enables water rise towards the exposed surface of the soil. This can lead to water-logging of plant roots during wet periods and water stress during dry periods, both of which reduce plant growth and crop yield.

25 To enhance plant growth, farmers use various agricultural implements to loosen and breakup the soil, enabling superior root penetration and soil drainage. Such cultivation techniques are collectively referred to as tillage. Examples of shallower tillage techniques are harrowing with discs, "min-till" cultivation with a combination of harrow discs for surface tilling and deeper tines for penetrating and tilling the soil to a deeper maximum "cultivation depth", and 30 rotary tilling, of which the rotary tilling typically provides the greatest depth of tillage. Deeper beneath the surface, "subsoil" cultivators are used to lift and shatter the soil structure, for example reaching depths of 60 cm (24 inches). Cultivators are typically drawn across fields by tractors, to which they are connected, commonly by either a three-point linkage by which the cultivator is cantilevered out behind the tractor, or in the case of a cultivator with a roller 35 by trailing from a hitching point on the tractor.

2

An exemplary tractor-mounted subsoil cultivator has an arrangement of legs descending from a frame, with each leg having a tool head in an arrangement of swept-back wings at the lower end, for example in an arrangement of two lateral wings transverse to the leg and a further wing rising up in front of the leg, or like a miniature plough. In use, the frame is 5 lowered to the desired level above the surface of the soil, such that the legs penetrate the soil and the tool heads are drawn through the soil, as the tractor advances. The greatest soil disturbance by the subsoil cultivator occurs at the chosen depth of the tool heads, referred to here as the "cultivation depth". The tool head lifts and cracks the soil, and may be additionally cut through the roots of weeds. After such cultivation, the roots of crop plants 10 are able to grow more easily through the disturbed soil, and the drainage is similarly improved.

Disadvantageously, the power required to draw the tool heads and descending legs of the subsoil cultivator through the soil requires substantial fuel consumption by the tractor, with a 15 corresponding expense and environmental impact. Further, the rate of fuel consumption increases with the depth of cultivation, at least in part due to the increasing length of the legs that penetrate into the soil.

Where the cultivation depth is controllable, and in particular with both the subsoil cultivator 20 and the min-till cultivator, the cultivation depth is selected by the farmer, based upon experience of each field, and the recent cultivation and crop yield histories. However, the characteristics of the soil can vary significantly between different parts of a field, both at the surface and at depth. In particular, the depth of the soil that would most benefit from cultivation (e.g. most compacted or heaviest) may vary throughout a field. Consequently, 25 known cultivation techniques may cultivate too deeply in some regions and at too little depth in other regions, resulting in undesirably high fuel consumption and lower crop yields.

SUMMARY OF THE DISCLOSURE

30 According to a first aspect of the present invention, there is provided a soil cultivation system comprising a soil cultivator and a depth control system,

wherein

35 the control system is configured to vary the cultivation depth of the soil cultivator in correspondence with a soil characteristic.

3

According to a second aspect of the present invention, there is provided a method of soil cultivation with a soil cultivation system comprising a soil cultivator and a depth control system,

5 the method of cultivating the soil in an area of land comprising cultivating soil by drawing a cultivator through the soil, and varying the cultivation depth of the cultivator in correspondence with a soil characteristic.

10 The soil characteristic may be soil resistance.

The soil characteristic may be electrical conductivity.

The soil characteristic may be combination of soil resistance and electrical conductivity.

15

The soil characteristic may be a characteristic of the soil at or proximate a location of the cultivator within an area of land.

The soil characteristic at a location within an area of land may be a plurality of characteristics 20 of the soil, each of the plurality of characteristics corresponding to a different soil depth.

The cultivation depth at a location may correspond to a depth at which the soil characteristic has a maximal value. The depth at which the soil characteristic has a maximal value may be the depth at which cultivation is most beneficial.

25

The cultivation depth at a location may correspond with a depth at which a weighted soil characteristic has a maximal value, wherein the weighted soil characteristic is the multiplication product of the soil characteristic and a cultivation depth weighting function that decreases with increasing soil depth. Accordingly, the cultivation depth may be determined 30 in correspondence with the benefit that may be provided by cultivation at a particular depth, but being weighted to reflect the increased fuel consumption of deeper cultivation.

The control system may comprise a look up table of values that correspond with a predetermined cultivation depth at each of a plurality of locations within an area of land, 35 wherein each predetermined cultivation depth corresponds with a soil characteristic.

4

The predetermined cultivation depth at a location may correspond to a soil characteristic at or proximate the location.

The predetermined cultivation depth at a location may further correspond to a historical crop 5 yield at or proximate the location.

It may be desirable to provide deeper cultivation in areas of low yield, which may be determined from crop yield data recorded during harvest. Accordingly, a cultivation depth weighting function may vary as a function of yield. Further, a minimum cultivation depth may 10 be determined in accordance with crop yield data to ensure that the soil is cultivated to a minimum depth sufficient to incorporate the level of waste (e.g. straw) lying on the surface at that location after harvest.

The control system may comprise a look-up table of values that correspond with a soil 15 characteristic at each of a plurality of locations within an area of land.

The control system may comprise a look-up table of values that correspond with a first plurality of soil characteristics at each of a second plurality of locations within an area of land, wherein each of the first plurality of soil characteristics corresponds with a different 20 depth.

The values may further correspond to a historical crop yield at or proximate the location.

The method may further comprise varying the cultivation depth of the cultivator in 25 correspondence with predetermined cultivation depths.

The method may further comprise varying the cultivation depth of the cultivator in correspondence with a historical crop yield.

30 The method may further comprise measuring the soil characteristic at a plurality of locations within an area of land prior to cultivating the land.

The method may further comprise measuring the soil characteristic at a plurality of depths at each location.

35

5

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

5 • Figures 1A and 1B schematically illustrate an exemplary soil structure prior to cultivation, and corresponding plant root growth in such a soil structure;

• Figure 2 schematically illustrates measurement of soil resistance;

• Figure 3 schematically illustrates a three dimensional map of soil resistance in a field;

• Figure 4 schematically illustrates a contour map of the optimum cultivation depth in 10 an area of land;

• Figure 5 schematically illustrates cultivation of land in which layers of soil having particular soil characteristics vary in depth; and

• Figures 6A and 6B respectively illustrate shallow and deep maps of the electrical conductivity of a field.

15

DETAILED DESCRIPTION

Like reference numerals refer to like elements throughout.

20 Figure 1A shows a sectional view through soil beneath the exposed surface. The soil comprises a series of layers S1 to S5 at increasing depths, with differing physical properties. A and B indicate the depth to which respectively more and less common tillage techniques reach, with corresponding fine, medium and coarse soil compaction in layers S1 to S3. Typically, the uppermost layer of soil S1 is the least compacted, having been most 25 intensively tilled. However, the soil characteristics vary as a function of their physical composition, as well as their history of tilling.

Deeper layers S4 and S5 are shown having a more compacted structure. In particular, layer S4 has the most compacted structure, providing a protective shelf through which plant roots 30 experience the greatest difficulty in penetrating, as is illustrated in Figure 1B. Accordingly, layer S4 is the layer that would most benefit from being subsoil cultivated.

Prior to cultivation of an area of land, physical characteristics of the soil are analysed at an array of locations across the land. The soil resistance varies with the water loading of the 35 soil, and for the purposes of standardisation, the soil resistance measurements are

6

preferably made when the soil is wettest (commonly referred to as being at "field capacity"), for example in January to March, in the northern hemisphere.

One soil characteristic that may be measured is the soil resistance F, which is the force 5 required to insert a penetrometer 100, as illustrated in Figure 2. The soil resistance measurements are recorded to a look up table in a control system 102. The soil resistance F varies as a function of depth beneath the surface, and so by taking repeated readings as the penetrometer 100' is inserted, soil resistance F' at greater depths d' can be measured, and a soil resistance profile as a function of depth can be determined. Accordingly, by use 10 of the penetrometer 100 at suitable intervals throughout the area of a field, it is possible to build up a three dimensional map of the soil resistance throughout the field, as illustrated in Figure 3. For example, penetrometer readings may be taken at 2.5cm depth increments, up to a maximum depth of 60cm, in an array of locations spaced across the land at 25m intervals. For such large-scale mapping of soil resistance, the penetrometers are 15 advantageously part of a mechanised process, with measurements being taken from a vehicle driven up and down the field at fixed intervals, producing thousands of data points from a typical field, each linked to its corresponding location, through a geographical positioning system (GPS).

20 From each soil resistance profile it is possible to determine an optimum cultivation depth at which to cultivate the land around each measurement location, i.e. in an area extending approximately half way to the adjacent measurement locations. Figure 4 shows an exemplary contour map of the optimum cultivation depth, which stored in an electronic lookup table, and used in dynamically controlling the level of the cultivator or part of the 25 cultivator (e.g. in the case of a min-till cultivator, just the penetration depth of the tines may be controlled). Alternatively, the optimum cultivation depth may be determined in the field, based upon the measurement data.

Figure 5 illustrates the cultivation of a field in which the layers of soil S1 to S5 vary in depth, 30 and which illustrates the way in which the cultivation depth D and D' of the cultivator 104 and 104' differs between different locations. In this case the optimum cultivation depth corresponds with the middle of the most compacted soil layer, S4. Accordingly, as the tractor 106 traverses the land, drawing the cultivator 104 through the soil, and monitoring the position of the cultivator through a GPS system, the cultivation depth D and D' is dynamically 35 varied, under the control of the control system 102, in correspondence with the predetermined cultivation depth data stored in a look-up table for that location (or preferably, suitable values may be determined across an area of land, through mathematical smoothing,

7

based upon data from the measurement locations). Consequently, by optimising the cultivation depth, water flow and subsequent crop yields can be increased, and in the case that only a shallow cultivation depth is required, fuel consumption may be reduced.

5 Although Figure 5 illustrates dynamic control of the cultivation depth of a subsoil cultivator, it will be appreciated that this method is applicable to other forms of cultivation, such as in the dynamic control of the cultivation depth of the tines of a min-till cultivator.

In the case that the cultivator is mounted on a three-point linkage at the rear of the tractor, 10 the linkage may be controlled, to control the cultivation depth. In the case that the cultivator is a hitched trailer, the cultivator may have separate adjustment systems (e.g. hydraulic systems) for varying the cultivation depth.

A further soil characteristic that can be determined is the electrical conductivity of the field by 15 use of an electrical conductivity scanner. The scanner has a transmission coil that transmits an electric field into the soil. Receiver coils receive the signal re-radiated from the soil. By use of receiver coils with different electromagnetic field reception characteristics, it is possible to detect different signals (e.g. receiver coils with a horizontal and a vertical coil axis, providing two detected signals), each indicative of soil electrical conductivity to a 20 different depth. Due to the distributed nature of the electromagnetic process, the received signals are indicative of soil characteristics across a range of depths, rather than corresponding to a single depth measurement. Figures 6A and 6B illustrate maps of the electrical conductivity to approximately 40cm and 120cm respectively (the darker regions correspond to regions of higher electrical conductivity). Regions of higher electrical 25 conductivity may have soil composed of finer particles (e.g. clay), which is more difficult for roots to penetrate, and preferentially benefit from cultivation. Accordingly, the optimum cultivation depth D may be determined based upon the differences between different electrical conductivity measurements (with or without weighting for the increase in fuel consumption with depth, and/or crop yield data).

30

Like the soil resistance measurements, the electrical conductivity measurements are also preferably made when the soil is wettest (at "field capacity").

As well as the electrical conductivity measurements, it may be beneficial to conduct some 35 additional mechanical investigations of the soil by test excavations in some test locations to further inform the interpretation of the measurements, for example by confirming the

8

particular soil types corresponding with different electrical conductivity measurements. Alternatively, or additionally, a few penetrometer measurements may be made.

The cultivation depth may be determined from either the soil resistance measurements or 5 the electrical conductivity measurements alone. However, advantageously the optimum cultivation depth may be determined based upon both a soil resistance depth profile and an electrical conductivity depth profile at each measurement location, which may provide superior optimisation of the optimum cultivation depth, compared with optimisation based upon only one type of depth profile. For example, the electrical conductivity data may 10 enable further weighting to be applied to the soil resistance data.

Where repeat measurements have been made (e.g. in successive years), the electrical conductivity data from different measurements may be used to adjust the penetrometer measurements, to account for variations in weather conditions, in a 'normalisation' process.

15

Crop yield data recorded during a previous harvest, for example showing the crop to waste ratio of cereal crops, may be collected at a plurality of locations into a crop yield map. Accordingly, the optimum cultivation depth may also determined based upon the both the crop yield and one or both of the soil resistance and electrical conductivity depth profiles.

20

It may be desirable to provide deeper cultivation in areas of low yield, which may be determined from crop yield data recorded during harvest. Accordingly cultivation may additionally be weighted to favour poor yield areas, for example by cultivating more deeply, by applying a cultivation depth weighting function that reduces by less with increasing 25 distance than in regions of higher yield.

Further, in the case that crop waste (e.g. straw) remains on the surface, following the harvest, and prior to (shallow) cultivation, a minimum cultivation depth may be determined in accordance with crop yield data to ensure that the soil is cultivated to a minimum depth 30 sufficient to incorporate the level of any waste lying on the surface at each location. For example, each tonne of waste, may require at least a given depth of soil for incorporation, and this may be reflected in the cultivation depth, which should always be sufficient.

Although in the above example cultivation has been discussed in relation to subsoil 35 cultivation, the invention is equally applicable to min-till cultivation.

The figures provided herein are schematic and not to scale.

9

Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps.

5 Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

10 Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or 15 process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel 20 combination, of the steps of any method or process so disclosed.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents 25 are incorporated herein by reference.

Claims

CLAIMS 10

1. A soil cultivation system comprising a soil cultivator and 5 a depth control system,

wherein the control system is configured to vary the cultivation depth of the soil cultivator in correspondence with a soil characteristic.

10

2. A soil cultivation system according to claim 1, wherein the soil characteristic comprises soil resistance.

3. A soil cultivation system according to claims 1 or 2, wherein the soil characteristic comprises electrical conductivity.

15

4. A soil cultivation system according to any one of claims 1, 2 or 3, wherein the soil characteristic is a characteristic of the soil at or proximate a location of the cultivator within an area of land.

20

5. A soil cultivation system according to any preceding claim, wherein the soil characteristic at a location within an area of land is a plurality of characteristics of the soil, each of the plurality of characteristics corresponding to a different soil depth.

6. A soil cultivation system according to any preceding claim, wherein the cultivation 25 depth at a location corresponds to a depth at which the soil characteristic has a maximal value.

7. A soil cultivation system according to any one of claims 1 to 5, wherein the cultivation depth at a location corresponds with a depth at which a weighted soil characteristic has a

30 maximal value, wherein the weighted soil characteristic is the multiplication product of the soil characteristic and a weighting function that decreases with increasing soil depth.

8. A soil cultivation system according to any preceding claim, wherein the control system comprises a look up table of values that correspond with a predetermined cultivation

35 depth at each of a plurality of locations within an area of land, wherein each predetermined cultivation depth corresponds with a soil characteristic.

11

9. A soil cultivation system according to any preceding claim, wherein the predetermined cultivation depth at a location corresponds to a soil characteristic at or proximate the location.

5 10. A soil cultivation system according to any preceding claim, wherein the predetermined cultivation depth at a location further corresponds to a historical crop yield at or proximate the location.

11. A soil cultivation system according to any one of claims 1 to 7, wherein the control 10 system comprises a look-up table of values that correspond with a soil characteristic at each of a plurality of locations within an area of land.

12. A soil cultivation system according to any one of claims 1 to 7 or 11, wherein the control system comprises a look-up table of values that correspond with a first plurality of soil

15 characteristics at each of a second plurality of locations within an area of land, wherein each of the first plurality of soil characteristics corresponds with a different depth.

13. A soil cultivation system according to claim 12, wherein the values further correspond to a historical crop yield at or proximate the location.

20

14. A method of soil cultivation with a soil cultivation system comprising a soil cultivator and a depth control system,

the method of cultivating the soil in an area of land comprising 25 cultivating soil by drawing a cultivator through the soil, and varying the cultivation depth of the cultivator in correspondence with a soil characteristic.

15. A method according to claim 14, further comprising varying the cultivation depth of 30 the cultivator in correspondence with pre-determined cultivation depths.

16. A method according to claim 14, further comprising varying the cultivation depth of the cultivator in correspondence with a historical crop yield.

12

17. A method according to any one of claims 14, 15 or 16, further comprising measuring the soil characteristic at a plurality of locations within an area of land prior to cultivating the land.

18. A method according to claim 14, further comprising measuring the soil characteristic at a plurality of depths at each location.

19. A soil cultivation system substantially as hereinbefore described with reference to the accompanying description and any one of the Figures.

20. A method of soil cultivation substantially as hereinbefore described with reference to the accompanying description and any one of the Figures.

Amendments to the claims have been fild as follows

1. A soil cultivation system comprising a soil cultivator and

5 a depth control system,

wherein the depth control system comprises a look-up table of predetermined values that correspond with a soil characteristic at each of a plurality of locations within an area of land, and

10 the depth control system is configured to vary the cultivation depth of the soil cultivator in correspondence with the predetermined values.

15

3. A soil cultivation system according to claims 1 or 2, wherein the soil characteristic CO comprises electrical conductivity.

4. A soil cultivation system according to any one of claims 1, 2 or 3, wherein the soil O 20 characteristic is a characteristic of the soil at or proximate each of the plurality of locations.

CM

25

5. A soil cultivation system according to any preceding claim, wherein the soil characteristic at each of the plurality of locations is a plurality of characteristics of the soil, each of the plurality of characteristics corresponding to a different soil depth.

6. A soil cultivation system according to any preceding claim, wherein the cultivation depth at each of the plurality of locations corresponds to a depth at which the soil characteristic has a maximal value.

30 7. A soil cultivation system according to any one of claims 1 to 5, wherein the cultivation depth at each of the plurality of locations corresponds with a depth at which a weighted soil characteristic has a maximal value, wherein the weighted soil characteristic is the multiplication product of the soil characteristic and a cultivation depth weighting function that decreases with increasing soil depth.

35

8. A soil cultivation system according to any preceding claim, wherein the look-up table of predetermined values corresponds with a predetermined cultivation depth at each of the

13

plurality of locations, wherein each predetermined cultivation depth corresponds with a soil characteristic.

9. A soil cultivation system according to claim 8, wherein the predetermined cultivation depth at each of the plurality of locations corresponds to a soil characteristic at or proximate the location.

10. A soil cultivation system according to claim 8 or 9, wherein the predetermined cultivation depth at each of the plurality of locations further corresponds to a historical crop yield at or proximate the location.

11. A soil cultivation system according to any preceding claim, wherein each of the predetermined values in the look-up table corresponds with a plurality of soil characteristics corresponding to different depths, at each of the plurality of locations.

12. A soil cultivation system according to any preceding claim, wherein the predetermined values further correspond to a historical crop yield at or proximate each of the plurality of locations.

13. A method of soil cultivation with a soil cultivation system comprising a soil cultivator and a depth control system,

wherein the depth control system comprises a look-up table of predetermined values that correspond with a soil characteristic at each of a plurality of locations within an area of land,

the method of cultivating the soil in an area of land comprising cultivating soil by drawing a cultivator through the soil, and varying the cultivation depth of the cultivator in correspondence with the predetermined values.

14. A method according to claim 13, wherein the predetermined values comprise predetermined cultivation depths.

14

15. A method according to claim 14, wherein the predetermined values comprise values of a soil characteristic, and the depth control system is configured to determine an optimum cultivation depth based upon the predetermined values.

16. A method according to claim 15, wherein the predetermined values comprise soil resistance values.

17. A method according to claims 15 or 16, wherein the predetermined values comprise electrical conductivity values.

18. A method according to any one of claims 15, 16 or 17, wherein the predetermined values further comprise historical crop yield values.

19. A method according to any one of claims 13 to 18, further comprising measuring the soil characteristic at the plurality of locations within the area of land prior to cultivating the land.

20. A method according to any one of claims 13 to 19, further comprising measuring the soil characteristic at a plurality of depths at each location to determine the predetermined values.

21. A soil cultivation system substantially as hereinbefore described with reference to the accompanying description and any one of the Figures.

22. A method of soil cultivation substantially as hereinbefore described with reference to the accompanying description and any one of the Figures.

15