AU719532B2

AU719532B2 - Aeration of soil

Info

Publication number: AU719532B2
Application number: AU49282/97A
Authority: AU
Inventors: Rudolf Lodewyk Veldman
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-12-24
Filing date: 1997-12-23
Publication date: 2000-05-11
Anticipated expiration: 2017-12-23
Also published as: AU4928297A

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT *q Name of Applicant(s): Actual Inventor(s): Address for Service: Invention Title: RUDOLF LODEWYK VELDMAN RUDOLF LODEWYK VELDMAN CULLEN CO., Patent Trade Mark Attorneys, 240 Queen Street, Brisbane, QId. 4000, Australia.

AERATION OF SOIL *.o Details of Associated Provisional Applications: Nos. P04396 filed 24 December 1996 The following statement is a full description of this invention, including the best method of performing it known to me 1. I 2 BACKGROUND OF THE INVENTION This invention relates to the aeration of wide acre soils to increase their fertility for crop production.

Soil aeration is important for optimising crop growth and crop resistance to pestilence and adverse weather conditions, particularly drought. In order to be effective, the aeration should be such as to enable any entrained toxic materials to be eluted from the soil when the soil becomes saturated following irrigation or rain.

To date, no truly effective method of soil aeration has been proposed which will meet this requirement.

OBJECT OF THE INVENTION *It is therefore an object of the invention to 15 provide a method of aeration which enables salts such as aluminum and the like which inhibit plant growth, to be eluted in a controlled drainage system.

SUMMARY OF THE INVENTION *eee** According to one aspect of the present invention 20 there is provided a method of soil aeration which comprises the steps of:breaking-up the soil to a sufficient depth to 000005 S"provide a cultivatable layer and so as to fracture any hard pan layer within approximately 25 1.2m of the soil surface; the breaking-up of the .e S"soil being such as to increase the pore spaces so that upward capilliarity of water within the soil is replaced by downward gravitational forces; and (ii) excavating a plurality of spaced trenches to a depth of approximately 1.2m in the soil; the trenches being spaced from one another by a sufficient distance to enable excess water passing into the soil to be circulated to the trenches.

DETAILED DESCRIPTION OF THE INVENTION It has been found that if the trenches have a depth of less than 1.2 metres the percolation of toxic t 3 salts into them from the surrounding soil does not occur.

The depth of 1.2 metres appears to act as a triggering point at which this phenomenon occurs and no rational reason can be advanced as to why this should be so.

Depths of greater than 1.2 metres are not economically practical to excavate and show a marked decrease in the leaching phenomenon.

Preferably, the trenches should have sloping walls so that they have a substantially V-shaped profile.

The bottom of the trench will, however, normally be flat.

A typical trench will be approximately two metres wide at the surface and approximately 0.3 metres wide at its bottom. The bottom will be suitably level so that water collecting therein is not drained away.

15 As noted above, a plurality of trenches is S excavated. Such trenches will preferably be parallel and must be separated by no more than about 60 metres to ensure optimal aeration and drainage of toxic salts. The soil between the drains is cultivated and, for heavy soils S 20 such as clays, mole drains are preferably located running into the main trenches at right-angles thereto every two to three metres. For medium soils, such mole drains can S"have greater effective separations at around four to six metres.

25 The trenches will normally be left open, however S"they can be back-filled with a drainage material if need be. Furthermore, it may in some instances be appropriate to cover the bottom of the trenches with plumber covers, typically 45-60cm wide, and to place branches or other light-weight material thereon, and backfill the drain for a depth of 30-45cm.

According to another aspect of the invention, the trenches are replaced by tunnels. Such tunnels extend to the same maximum depth as the trenches but will preferably be more than 0.6 metres below the soil surface.

The trenches and tunnels function to concentrate all the plant toxic salts from the surrounding soil and therefore enable plant growth to be promoted. The plants develop more stable root systems which is an advantage in adverse weather conditions, and are healthier and therefore more resistant to pestilence and drought.

The steps of breaking-up the soil and then excavating the trenches can, of course, be reversed with the same overall effect being produced.

For the large scale aeration of soil, the most effective manner of cultivation is to firstly excavate the trenches using, for instance, a drain ditcher and then, utilising the biggest types of rippers, for instance bulldozer rippers, to rip the intervening areas between the trenches leaving an adequate free board strip along the trenches, one half to one bulldozer width, so that the trenches are prevented from collapsing due to the trafficking of tractors and other implements.

BRIEF DESCRIPTION OF THE DRAWINGS ee Figure 1 is a soil profile which is formed according to the present invention, Figure 2 is a schematic representation showing moisture flow within the soil formed according to the present invention, and Figure 3 is a sketch plan showing the layout of S"trenches and mole drains in heavy soils.

DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the invention will now be described with reference to the drawings, in all of which like reference numerals refer to like parts.

In Figure i, the soil 10 is aerated in such a manner that capillary action is replaced by gravitational forces. To accomplish this, bulldozer rippers 11 are used to crack the soil wide and deep and to crack and/or shatter the existing hard pan layer 12 to increase the natural pore space to fist-sized air pockets. Trenches 13 measuring 1.2 metres in depth, two metres wide at the top and 0.3 metres wide at the bottom, are excavated using a rotary ditcher such as a Dondi DBR.95.M. These trenches ensure that the soils do not revert to their former states. Gravity forces replace anti-gravity capillary forces and "communicating vessel" gravity pressure lines discharge excess water to the bottom of the trenches turning convex into concave drainage patterns as illustrated in Figure 2. In this manner soil moisture is stored (soil profile filled to capacity) to sustain crop growth during periods of drought.

In Figure 2, the soil moisture flow is illustrated. This shows how moisture migrates to the trenches under the forces of gravity, rather than to the surface of the soil where it would be lost by evaporation.

Reference numeral 14 shows a shattered hard pan and reference numeral 9 shows the water table.

Figure 3 illustrates two trenches 15, 16 having the same profile as the trench 13 of Figure i. The 15 trenches are substantially parallel to one another and their longitudinal axes are separated by 60 metres. This is the optimal separation for effective aeration of the soil and leaching of salts to occur. The space "A" between the trenches has been broken up with bulldozer rippers and then cultivated using a rotary hoe or like equipment to a normal cultivation depth.

Mole drains 17-27, are cut at right angles to the trenches. The mole drains are located at a depth of 1.2 metres in staggered arrangement and are spaced from 25 one another by 4-6 metres for medium to heavy soils and 2- 3 metres for clay type soils. The mole drains are formed using a tractor drawn mole drainer of conventional type.

The invention provides a much needed method for increasing crop production throughout not cultivatable areas of the world.

Whilst the above has been given by way of illustrative example of the invention, many modifications and variation may be made thereto by persons skilled in the art without departing from the broad scope and ambit of the invention as herein set forth.

Claims

1. A method of soil aeration which comprises the steps of:- breaking-up the soil to a sufficient depth to provide a cultivatable layer and so as to fracture any hard pan layer within approximately 1.2m of the soil surface; the breaking-up of the soil being such as to increase the pore spaces so that upward capilliarity of water within the soil is replaced by downward gravitational forces; and (ii) excavating a plurality of spaced trenches to a depth of approximately 1.2m in the soil; "15 the trenches being spaced from one another by a sufficient distance to enable excess water ee passing into the soil to be circulated to the trenches.

2. A method of soil aeration as claimed in claim 1, S 20 in which steps and (ii) are reversed.

3. A method of soil aeration as claimed in claim 1 or claim 2, in which the soil is broken-up using rippers or tynes of a bulldozer.

4. A method of soil aeration as claimed in any one 25 of claims 1-3, in which the trenches are substantially V- shaped in profile and have a flat bottom.

A method of soil aeration as claimed in claim 4, in which the trenches are approximately 2 metres wide at the top and 0.3 metres wide at the bottom.

6. A method of soil aeration as claimed in any one of the preceding claims, in which the trenches are substantially parallel to one another.

7. A method of soil aeration as claimed in claim 6, in which the trenches are spaced apart from one another by approximately 60 metres.

8. A method of soil aeration as claimed in any one of the preceding claims and including a multiplicity of mole drains running into the trenches.

9. A method of soil aeration as claimed in claim 8, in which the mole drains are at right angles to the trenches.

A method of soil aeration as claimed in claim 8 or claim 9, in which the mole drains are spaced apart from one another by approximately two to three metres for heavy soils and by approximately four to six metres for medium soils.

11. A method of soil aeration as claimed in any one of the preceding claims, in which the trenches are back- filled with drainage material.

12. A method of soil aeration which comprises the steps of:- breaking-up the soil to a sufficient depth to provide a cultivatable layer and so as to fracture any hard pan layer within approximately 1.2m of the soil surface; the breaking-up of the soil being such as to increase the pore spaces so that upward capilliarity of water within the soil is replaced by downward gravitational forces; and forming a plurality of spaced tunnels at a maximum depth of approximately 1.2m in the soil; tunnels being spaced from one another by a 25 sufficient distance to enable excess water passing into the soil to be circulated to the tunnels.

13. A method of soil aeration as claimed in claim 12, in which steps and are reversed.

14. A method of soil aeration as claimed in claim 12 or claim 13, in which the tunnels are at least about 0.6 metres below the soil surface.

A method of soil aeration as claimed in any one of claims 12 14, in which the tunnels are substantially parallel to one another.

16. A method of soil aeration as claimed in any one of claims 12-15, in which the tunnels are spaced apart 8 from one another by approximately 60 metres.

17. A method of soil aeration substantially as herein described with reference to the accompanying drawings. this 2 3 rd day of December 1997 RUDOLF LODEWYK VELDMAN By their Patent Attorneys CULLEN~ CO. 's