AU2004202020A1 - Laminated digging tool - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT LAMINATED DIGGING TOOL The following statement is a full description of this invention, including the best method of performing it known to us.

LAMINATED DIGGING TOOL This invention relates to improvements in devices for digging soil.

Pasture and cropping soils in Australia are declining in productivity. Increasingly these soils have "collapsed", they have lost their "structure" or their ability to form "crumbs" and are being compacted.

Overstocking, heavy machinery and the soil inverting, mould-board plough type implements and the use of farm chemicals all combine to contribute to this problem.

Nitrates are added to grain crops at 250 k/ha in urea and other nitrate fertilizers which attack and consume organic matter in the soil. The organic matter is lost. The organic matter is needed to form sugars that act as the glue to adhere soil particles together to form crumbs or aggregates which are the fundamental of soil structure. (Howard) Minimum tillage implements that only dig the top 50mmn of soil pulverize and fragment the soil aggregates fur-ther contributing to the soil structure collapse. The underside of the minimum tillage implements smear the soil leaving an impermeable hardpan or plough pan.

As a result wind blows the fine soil particles away and runoff erodes the surface soil and washes it away.

Conventional farming techniques have deprived the top layer of soil of enough organic matter for the individual particles of sand, silt and clay to adhere together to form crumbs and build adequate soil structure. The "collapsed" soil particles are compacted by stock, machines and mould-board type implements eg. disc plough, scarifiers. The latter place a seal or smear or shear line under the inverted soil. The seal was part of the design of the mould-board plough which was developed in Northern Europe where the seal provided a drain for the high rainfall over the undulating landscape serviced by river systems that flowed quickly to the sea.

Mould board plough implements have been less successful in Australia due to our harsh climate, the flat landscape and rivers that for long periods do not flow.

Over time the seal forms a compacted layer 50 to 75 mm below the surface. Air, water, sunlight and plant roots cannot enter this compacted layer or hardpan. Plant roots are unable to obtain enough nutrients, minerals, air, water and energy for growth. Runoff washes soluble soil salts, from the collapsed soil in the top layer, over the hardpan to the low points. The water ponds, evaporates and leaves salty, unproductive soil.

The acids, dilute sulphuric and hydrofluoric acid, attack the organic matter in the soil.

Sulphuric acid comes from the manufacture of superphosphate and fluoride is an impurity which reacts with water to form the short lived hydrofluoric acid. Soil conditions such as lime (a base) are added to neutralize the acid. Salt plus water results. These are flushed to the low points. Super mobilizes salts in the soil as it is 47% gypsum (CaSo 4 and the calcium mobilizes sodium (by ion exchange) which is washed to the low points.

Similarly with nitrate fertilizers which mobilize chloride from the soil. Pesticides which are salts or degrade to salts are used to control weeds instead of ploughing.

Soil salting is initiated by the collapse of soil structure (Howard). The collapsed soils become compacted and form impermeable layers below the surface. The presence of impermeable layers and hardpans in the soil have been claimed to cause soil salting by Howard, Cope (Victoria), Rowan (Victoria), Whittington (Western Australia) and Conacher (Western Australia) (refer References and Drawings 1 3) Salt in transported from higher areas by water in the soil layer above the impermeable layer by tbroughiflow to the low areas where soil salting occurs.

lIn direct contradiction to its own reports of 1958 (Cope) and 1971 (Rowan)regarding dryland salinity, the Victorian government claims that soil salting is caused by rising groundwater. "The Committee is aware that the development of saline seeps has been attributed to two different mechanisms. In the first, the seep is viewed as the outcome of rising regional or localised watertables. In the second, the seep is seen to be the result of local rainfall which, after entering the soil, is prevented from further downward movement by a 'hardpan'. Water flows over this layer to the seepage zone. The hardpan layer may be naturally occurring or a layer of reduced permeability resulting from soil compaction. On the basis of the information provided to the Committee by the Soil Conservation Authority the first mechanism is clearly more widespread in Victoria. However the Committee accepts that the second mechanism may also operate in parts of the State and would welcome further investigation into the aspect." (Salinity Committee) Salt officials believe that rising groundwater brings salt to the fann paddock surface along fine, hair-like tubes called capillaries. The groundwater rises by capillary action. For this to happen the capillary must reach the surface and must not be blocked. If capillary action did bring salt to the surface the low points of paddocks would contain no salt. The pressure head of rain or irrigation water that ponds there would flush fresh water back down the capillary. In every instance it is the low points where salt concentrates. On the surface.

After the water evaporates. The low points are the most salted part of the paddock! The reason for this concentration is that the capillaries do not reach the surface. They are blocked. Groundwater cannot reach the surface and ponds cannot drain as the top layer of soil is compacted and is impermeable.

Lake Frome in the far north of South Australia exposes this fallacy. The bed of Lake Fromne is always moist as it is in contact with rising, saline groundwater. The annual rainfall is 140mm and the evaporation rate is 3 metres a year. According to the rising groundwater theory the salt crust bed of Lake Frome should have been 5 metres thick. The CSIRO found a crust only 5mm thick. This salt came from surface runoff and so did the salt measured up to 1 metre below the lake bed. The intermittent rainfall that fills the lake was enough to push the saline, rising groundwater down! (ECOS) The presence of salted low points of paddocks in the much higher rainfall areas of Victoria (plus regular waterings in irrigated areas) with much lower evaporation rates proves that salt does not come to the surface by capillary action as it would be washed back down, like at Lake Frome.

Soil salting is a gradual process with increasingly obvious effects. The flat, ridges and depression landscape or "rolling" landscape (Cope) plays a highly significant role.

Chemical fanning practices in the hot, dry climate degrade soils that have a structure that quickly collapses without organic matter. Early symptoms of soil salting are increasing acidity, soil structure collapse, change of colour of pasture and crops from blue green to yellow green, soil colour lightens (change from dark to lighter hues), water pools on surface, presence of deep rooted weeds, sedges, tussocks and later barley grass, dwarf barley grass and succulents, stock congregate and feed preferentially in salt affected areas of paddocks (Cope).

Pioneering attempts at ploughing of the soil in Australia had mixed results. In the late 1 9'h century wheat was grown in the far north of South Australia while rainfall was good. "So successful and rapid was the movement that the idea that "the rain follows the plough" was soon invoked as one of the reasons for the success of the wheat harvest, and settlement penetrated too far north and east, only to retreat in later years when the normal seasons and droughts returned" (Powell, Williams p65-66) The inventors place great significance in the experience of the South Australian wheat farmers as long term use (10 years) of the laminated digging tool has resulted we believe in an increase in rainfall locally. The inventors believe that ploughing the virgin soil in the far north of South Australia would have released moisture (increasing humidity) and gases that combined with the proximity of the Flinders Ranges (an orographic barrier) resulted in increased thunderstorm activity (Jeans, Gentilli p26). The continued ploughing would have created a hardpan which sealed and stopped the moisture and gas release so that dry conditions returned.

The importance to agriculture of soil structure and compaction has been known for a long time.

Conventional farming has not addressed the main issue of soil collapse and compaction.

However the problem has been known about since early last century. Subsoilers that broke the soil to 400 -450 mim but did not turn it over have been used with success since that time.

An example is the Rackheath Plough built mostly from timber in the 1830's. (Refer to Drawing 4) During the 1960's in Australia a new plough was developed. The "aeration" plough grew from the "chisel" plough. The latter is a spring steel tined implement, semi circular in shape built from rectangular section steel with a leading edge point. (Refer to Drawing The tines are attached to the fr-ame and are pulled through the soil at a depth greater than the hardpan. The chisel plough was ineffective due to the high resistance loads as the chisel plough tine presented its largest cross sectional dimension to the soil. Vibration of the tine tended to further compact the soil.

The aeration plough was based on ancient wooden ploughs that consisted of a raking "leg" or "shank" with a detachable "shoe" or "point". The "aeration" plough presented its smallest shank dimension to the soil face and provided much less resistance than the chisel plough. The shank is rigidly supported to a frame by a point with a sacrificial shear pin (or "6stump jump" mechanism) to account for immovable objects (Refer to Drawing 6) The "aeration" plough applies three load systems to the soil simultaneously at a depth just below the hardpan (150 -250 mm). The first load system is imposed by two or more points side by side and acts on the soil ahead of the point as shown in the plan.(Refer to Drawing 7) The "beamn" of compacted soil is shattered by shear and tensile forces between the points.

Spacing of the points depends on the soil type, compaction and moisture content. The second load system is imposed by the point lifting the soil as shown in the side elevation Drawing. (Refer to Drawing 8) The third load system is imposed by the top of the point and cutting action of the shank as shown in the front elevation. (Refer to Drawing 9) The simultaneous application of the load systems creates numerous forces on the soil that breaks the soil apart. The size of the resulting particles decides the success of the ploughing process. The smaller the particle size the better. The larger the particles the greater the number of extra passes needed to further break these down. The smaller the particle the quicker air, water, sunlight and plant roots act to form soil structure.

The inventors have extensively researched "aeration" ploughs and found that there are some problems with their use. In attempting to overcome these problems the inventors developed the laminated digging tool.

The main problem of all existing points is that they wear very quickly. From the Drawings it is obvious that the maximum load is at the tip. The inventors have found that the sharpness of the tip is the most important factor in the efficiency of the shattering process.

The tip has to be sharp and retain its sharpness. All points available commercially wear very quickly as they are too soft. The tip becomes rounded especially in plan so that shattering of the soil is ineffective. The resulting particles are too big. Points need to be replaced twice a day which is costly and time consuming (typically a point costs $40 and an average plough would have 15 shanks replacement cost of $1200 per day). To reduce wear, ploughing is often carried out in soil that is too wet. Shattering does not occur and more compaction can occur due to the water acting as a lubricant. Large clods in excess of 300mm diameter can also be formed if the soil is not dry enough. If the soil is too dry the rate of wear, fuel and maintenance costs rapidly increase using commercially available points.

The laminated digging tool has been designed to operate under the driest conditions i.e. for maximum shattering effect resulting in the smallest particles. Dry conditions require maximum strength and maximum resistance to wear.

The inventors have found that for a point to retain its sharpness it has to: have high strength at high temperatures have high surface resistance to wear, not chip or crack retain its shape with uniform resistance to wear be ductile rather than brittle dissipate heat The invention applies to all forms, shapes and configurations of the tip. However for agricultural applications these factors are constrained by the need for the tip to: concentrate the applied loads and so apply maximum breaking and lifting forces on the soil at maximum depth.

Minimize resistance or drag forces by being compact and have a low surface area Not impose a seal or smear under it that could lead to hardpans forming at greater depth.

The inventors found the truncated triangular pyramid shape to be the most efficient for agricultural use. (Refer to Drawing Solid tips of steel and tungsten were trialled. but were found to be too brittle the tip rapidly chipped or broke off.

Horizontal layers of tungsten were then trialled with the laminations connected with silver solder. The connections failed. However when nickel bronze was used the tip proved to be effective. Any connections can be used in the laminated digging tool including welds, solder, bronze, glue, fuising, rivets, bolts, shear connections or interlocking shapes or any combination of these. An example of the laminated digging tool is shown below (Refer to Drawing 11) The laminated digging tool laminations can be of any material including metal(s), ceramic(s), alloy(s), fibre(s), compound(s) or combination of any of the above.

The laminated digging tool wears so that it remains sharp. (Refer to Drawing 12) For the trial models recycled tool tungsten was used. The laminations were approx. thick and were isosceles triangle shape with a base width of 15mm and a height of cuffing tip to base of approx 15mm. (Refer to Drawing 13) The most efficient angle of rake of the leading edge of the laminated digging tool was found to be 200 when used as a tip for a "Wallace" point. However the invention is not constrained to this angle of rake as the invention applies to all angles of rake. The preferred angle of point (plan) was 650 but the invention applies to all angles of point, 00 <51800.

The thickness of laminations used in the trial models of the laminated digging tool varied from 6mm to 4mm. However the invention is not constrained to these thicknesses. The laminations can be of any thickness and there can be any number of laminations to construct a laminated digging tool.

The preferred option of the invention for agricultural use is to combine it with a reinforced "Wallace" plough point. The invention is applicable as a tip or point for all other agricultural digging, ploughing, tilling and scarifying tools that require sharp points.

The "Wallace" plough point is constructed from three pieces of steel plate and has not been patented. The inventors, besides combining the "Wallace" point with his laminated digging tool has made improvements to this point which are part of this application. The "Wallace" point is a triangular pyramid shape as shown in Drawing 14.(Refer Drawing 14) The inventors chose the "Wallace" point as it has proven to be the most efficient at breaking and lifting soil. The inventor has reinforced the "Wallace" point along all its edges with tungsten cutting tool blocks, magnesium bronzed to the point, with a tungsten laminated digging tool at the tip as shown in Drawing 15. (Refer to Drawing The reinforced laminations applied to the "Wallace" point along its edges and the immediate laminations along each face not only protect the steel from wear but also lower resistance forces or drag so the point requires less effort to be pulled through the soil. The reinforcing laminations also act as containing boxes for soil so that a "boundary layer" of soil assists in the reinforcing process as shown in the Drawing. The spacing of the internediate reinforcing laminations is decided by the containing box's ability to contain soil i.e. how well the soil adheres to the point surface. (Refer to Drawing 16) The reinforcing laminations can be of any material, shape, size, configuration and can be connected by any method. The reinforcing laminations are applicable to all agricultural digging, ploughing, filling or scarifying tools.

The laminated digging tool has applications in agriculture, mining, excavation and construction.

The laminated digging tool can be a tip combined with some other digging point or can stand alone. (Refer to Drawing 17) The stand alone option can be solid, hollow or the laminations can be connected to an inner core using continuous or built up laminations.

The laminated digging point can be of any shape including conical, pyramid or wedge.

(Refer to Drawing 18) Ten years of trialling, the laminated digging tool with the preferred option "Wallace" plough has had results the inventors believe that are of great significance to Australian farmers. The trial was mostly conducted at "Cooinda"', Pyramid Hill, Victoria located on the Tragowal Plains which has a watertable of between 0.5 3.0 metres below the surface with the groundwater as salty as the sea. The land had previously been irrigated since the late 19"h century but had degraded to highly salty soil despite laser grading and a deep channel water re-use scheme.

The salty soil, as previously explained, was obvious especially in the large areas of ponds.

Acidity has declined, soil structure has been rebuilt, pastures and crops are blue green, soil colour has darkened, water does not pool on the surface, barley grass and succulents have been replaced by rye grasses and production increased. Over time the soil improves more and more.

Gases are released from the compacted soil. The inventors believe these gases are hydrogen sulphide from the anaerobic condition below the hardpan, hydrogen, radon from the uranium and radium that is a pollutant of superphosphate and that also naturally occurs in soils and other gases hazardous to soil biota and plants.

Water in dams that are filled with opaque, clayey water from irrigation channels turns clear, groundwater quality has improved with one sample of groundwater being 7e.c. units i.e. distilled water.

The soil purifies water and makes groundwater fresh at the surface of the watertable by stratification.

Excellent crops and pastures have been grown with groundwater 500mm below the surface with no ill effects.

Root depth of wheat plants has been measured at 2 metres below the surface. Wheat grown has high protein and is sought after by bakers for its excellent dough making capabilities and its high quality with no contaminants. The reason why produce has little or no contaminants from the pollutants already in the soil is that the plant roots are free to move away from the contaminant. Plant roots have been observed to bend 150 degrees. i.e.

head in the opposite direction to the original growth path. Stock taken to market are highly sought after and often top the market.

The results are summarised in the following illustration. The inventors believe further research is needed to fully explain and understand these results. However the laminated digging tool is the most significant aspect in allowing natural processes of the soil to occur. (Refer to Drawing 19)

REFERENCES

Howard, Sir Albert. "Agricultural Testament" Oxford University Press, 1940, pp 14 7 155 Cope, Frank. "Catchment Salting in Victoria" Soil Conservation Authority of Victoria, 1958 Rowan, J. N. "Salting on Dryland Farms in North Western Victoria," Soil Conservation Authority (Victoria) Melbourne 1971 Conacher, A "Dryland Agriculture and Secondary Salinity" Chapter 9, "Man and the Australian Environment" Ed Hanley and Cooper, 1982 Whittington, H. S. "Battle for Survival Against Salt Encroachment at 'Springhill"' Brookton, Western Australia, July 1975 Powell, J. M. "The Making of Rural Australia" Sorrell Publishing, 1974. Chapter 2, "The Parkland Towns ofAustralia and New Zealand" Williams, pp 6 5 66 Jeans, D. N. "the Natural Environment" Sydney University Press, 1986, Chapter 1, "Climate" Gentilli, p26 ECOS, No 47, Autumn 1986, "Evaporation From a 'Dry' Salt Lake" Bell, Summary of G. B.

Allison and C. J. Bames, Journal of Hydrology, 1985, 78, pp 2 2 9 242 Salinity Committee, Parliament of Victoria, Third Report to Parliament, "Salt of the Earth Final Report on the Causes, Effects and Control of Land and River Salinity in Victoria" October 1984, p26

Claims (10)

1. A laminated digging tool device comprising of two or more laminations connected together, with the laminations approximately parallel to the digging forces, that concentrates the applied digging forces to the extent that the material being dug is forced out of the path of the moving digging tool, the laminations giving an increase in strength, ductility, toughness, wear and heat dissipation compared to a digging tool of the same shape built from the lamination material alone, or any other material as detailed in Drawings 11, 12 and 13 and has applications in agriculture, mining, excavation and building construction.

2. The laminated digging tool of claim 1 can be of any shape, form or configuration, the laminations can be of any material and the connections can be of any type and there can be any number of laminations as detailed in Drawings 11, 12, 13, 17 and 18.

3. The laminated digging tool of claim I and 2 retains its efficiency at any depth and speed of movement through the soil.

4. The preferred option of the laminated digging tool of claim 1 for agriculture use is that detailed in Drawing number 13 The preferred option of the laminated digging tool of claim 1 for agriculture is further preferred to be combined with a reinforced "Wallace" point as detailed in Drawing

6. The preferred combination laminated digging tool of claim 5 breaks the seal, shear line or hardpan of compacted soils, preventing salt build up in the low points and rejuvenates soil that is already salted, prevents ponding of water, holds water in the soil and prevents through flow.

7. The preferred combination laminated digging tool of claim 5 shatters soils into particles so that air, water, sunlight (energy) can enter and leave soil as part of natural cycles and allows mineralization of the soil.

8. The preferred combination laminated digging tool of claim 5 shatters the soil so that plant roots grow deep which utilize the deeper nutrients and minerals with healthier, higher producing plants as detailed in Drawing 19.

9. The preferred combination laminated digging tool of claim 5 builds soil structure to the depth of ploughing, which this layer then acts as a soil mulch above the soil that has not been ploughed, this mulch and root growth promoting soil structure below plough depth, as detailed in Drawing 19. The preferred combination laminated digging tool of claim 5 changes soil colour to darker hues, allows even growth across paddocks, allows plants to change colour from yellow green of unploughed soil to the blue green of ploughed soil, and allows protein levels of crops to increase and with absolute minimum of contamination of produce from pollutants already in the soil.

11. The preferred combination laminated digging tool of claim 5 releases gases from the soil including hydrogen that lowers soil acidity, radon release that allows radiation levels to reach a natural balance, hydrogen sulphide and other gases hazardous to soil biota and plants.

12. The preferred combination laminated digging tool of claim 5 re-establishes productive grasses (clover, rye) rather than barley, dwarf barley, salt tolerant succulents or nothing 13 The preferred combination laminated digging tool of claim 5 promotes the water cycle, the vertical capillary movement of water through the soil and groundwater cycles which together promote increases in rainfall (a return to the farmnner's dictum that "the rain follows the plough"), discourages frosts and inhibits erosion by impeding lateral movement of water and soil and freshens saline groundwater under the soil, as detailed in Drawing 19. John Kirby 13 th May 2004