This invention relates to conservation apparatus. This invention has particular but not exclusive application to soil conservation, and for illustrative purposes reference will be made to such application. However, it is to be understood that this invention could be used in other applications, such as beach restoration, and silt entrapment for enriching fields or keeping silt away from dams. The erosion of topsoil from farmland is a serious agricultural problem in Australia and many other countries. A common technique for alleviating soil erosion is the formation of windrows or contour banks along contour lines such that the velocity of surface water is not permitted to rise to values at which erosion occurs, and soil which is eroded may be caught in the low-velocity region directly behind the contour banks.

Unfortunately, such contour banks are expensive to produce, necessitating between six and ten passes along each contour with a grader to form a typical bank profile. The process of forming the contour bank also results in soil disturbance for a significant distance on each side of the bank, resulting in a temporary but significant loss of land productivity following their construction. The present invention aims to alleviate the above disadvantages and to provide conservation apparatus which will be reliable and efficient in use. Other objects and

advantages of this invention will hereinafter become apparen .

With the foregoing and other objects in view, this invention in one aspect resides broadly in conservation apparatus including an elongate strip of water resistant barrier material which may be arranged in an upstanding attitude along a selected ground contour such that the flow of material across the ground contour may be restrained.

Suitably the strip material has an edge which is linear and which constitutes the upper edge of the strip material and which in use is maintained substantially horizontal.

The strip of material may be a composite strip and may be pervious or impervious to water but preferably the strip is formed from a plastics material and is relatively flexible whereby it may be stored and transported rolled into a roll or onto a drum for convenience, and whereby long sections thereof may be placed with minimal joins. Of course, if desired, the strip may be formed from a relatively rigid material and installed in sections along the contour, and may be overlapped for sealing at joins. The strip may be formed with any desired surface configuration such as plain strip. If desired, however, any or all of the height of the strip may include perforated apertured portions or portions with passages therethrough. The strip may be formed such that when buried a degree of reinforcement may be imparted to the ground into which the strip is inserted either by root entanglement of soil entrapment.

The strip may be provided with support means whereby it may be supported in an upright attitude above the contour. It is preferred, however, that the strip be formed of a height such that it may be placed by engaging a lower portion thereof with a trench formed along the contour, leaving an upper portion upstanding above the ground. Of course the full strip may be concealed below the ground to provide a security against further erosion of the ground. Suitably, the portion of the strip exposed above the ground is of the order of fifteen centimetres, although of course any suitable portion may be exposed as required. The strip of material may include a hollow or open top portion adapted to be exposed above the ground. An open portion may include flanges which extend laterally from the strip adjacent the ground which act to maintain and or return the upper portion of the strip of material to an upstanding attitude.

In a further aspect this invention provides installation apparatus for installing conservation apparatus or the like is disclosed, said installation apparatus including:- a ground-penetrating tyne which may be drawn through the ground by a prime mover, and strip guide means whereby elongate strip material may be operatively placed within the ground disturbed by said tyne.

Preferably, the strip guide means includes a longitudinal passage formed through the tyne and inclined downwards to the rear of the tyne such that strip material may be fed into a front upper position of the tyne and emerge

from a rear lower portion thereof. Of course, if desired, other strip guide means, such as a guide slot formed on one side of the tyne may be used.

The installation apparatus may further include roll handling means for storing and dispensing rolled-up strip material. Suitably, the prime mover is a dozer, front-end loader or the like whereby the roll handling means may be mounted to the front elevating linkage of the prime mover such that rolls of strip material may be conveniently retrieved from a transport vehicle and placed in a location relative to the tyne which allows strip material to be fed from a roll into the tyne.

The strip guide means may further include strip anchoring means associated with the tyne such that an end of the strip material may be secured thereto, whereby the strip material may be drawn along onto a groove formed by the tyne as it is drawn along the ground.

The prime mover may be provided with height indication means such that an operator may be assisted in installing the strip material along a selected contour. Suitably, the height indication means may include a laser light emitter emitting a rotating horizontal light beam, the emitter being supported at a fixed point relative to the ground, and a receiver mounted on the prime mover and adapted for indicating the height of the prime mover relative to the emitter.

In a further aspect this invention resides broadly in a

method of stabilizing exposed ground, the method including inserting elongate strips of water resistant barrier material in the ground substantially along spaced apart horizontal ground contours. The strip material may be buried fully in the ground with their upper edges adjacent the surface but preferably the strip material is buried in the ground with their upper portions upstanding above the ground.

In yet another aspect, this invention resides in a method of forming a barrier for restricting surface movement of water-borne material, said method including:- providing a quantity of flexible elongate strip material; providing a ground-engaging tyne having strip guide means associated therewith; attaching said tyne to a prime mover; engaging said strip material with said strip guide means; and energising said prime mover whereby said tyne is drawn through the ground and said strip material is placed within the trench formed by the passage of said tyne.

The method may further include the removal of the strip, or the raising of the strip to a higher elevation, after a desired buildup of material has occurred adjacent to it. In order that this invention may be more easily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate

preferred embodiments of the invention, wherein:-

FIG. 1 is a cross-sectional pictorial view of land including conservation apparatus according to the invention; FIG. 2 is a side view of a tyne for installing same;

FIG. 3 is a pictorial exploded view of the tyne of FIG.

2;

FIG. 4 illustrates an installation apparatus according to the invention; FIG. 5 illustrates a variation of the installation apparatus of FIG. 4.

FIG. 6 illustrates a variation of the tyne.

FIG. 7 illustrates a further application of the invention; FIG. 8 illustrates an open section form of strip material according to this invention, and

FIGS. 9 to 11 illustrates various installations of the invention.

The conservation apparatus 10 illustrated in FIG. 1 comprises an elongate flat strip of flexible material which is partially-buried in respective slits 11 formed in the ground 12 along spaced horizontal contours 13. The full depths of the strips 10 are diagrammatically exposed at the typical section illustrated. As shown, the strips 10 are positioned across the slope of the ground 12 whereby runoff water running down the slope of the ground is intercepted by the exposed portions 15 of the strip 10. Such interception

will either prevent continued movement of the runoff water down the slope or slow the flow rate of the runoff water down the slope of the ground 12. In either case, suspended solids will be deposited and retained behind the exposed portions 15. Furthermore, the reduced flow down the slope of the ground both over the strip 10 or in the topsoil below the exposed portions 15 is greatly reduced, minimising the eroding effect of the runoff water.

The strips 1.0 may be placed in position in the ground in any desired manner such as in end to end lengths in prepared trenches or slits but preferably each strips is placed continuously in unprepared ground through a tyne assembly 20 as shown.

The tyne assembly 20 includes a mirror-image pair of tyne halves 21 and 22 joined by bolts 23. The upper portion

24 of the tyne assembly 20 is apertured for attachment to a standard mounting for a ripper blade such as is found on the rear of dozers and the like. The lower portion 25 of the tyne assembly 20 includes a hardened cutting tip 26 which cuts through the lower face of a trench being formed by the tyne assembly 20. The central portion 27 of the tyne assembly 20 is formed with a rectangular slot 30 inclined downwards from the front to the rear of the tyne assembly 20.

As illustrated in FIG. 4, the tyne assembly 20 may be mounted to the rear of a crawler bulldozer 40, and the front blade of the bulldozer 40 may be removed and replaced with a

storage roller assembly 41, together with a guide chute 42 for conducting strip material 43 unwound from the roller assembly 41 into the slot 30.

In use, the storage roller assembly 41 is raised by the blade elevation apparatus 44 to a height suitable for transferring a roll of strip material 43 from the back of a truck or the like and into the roller assembly 41. The free end of the strip 43 is then conducted through the guide chute 4^ and the slot 30. The free end is then anchored into a starter trench 45 into which the tyne 20 is lowered to the depth necessary to expose the desired portion of the strip 43 above ground level. The free end of the strip is then anchored in position in any suitable manner, such as by being pegged into the ground and the bulldozer 40 is driven along a horizontal contour line passing through the starter trench 45. As it travels, the tyne 20 cuts a slit and strip material 43 is paid out from the roller assembly 41 and conducted into the slit so formed. If desired, scrapers, compactors or the like may be added to the rear of the tyne 20 to compact the ground on either side of the strip 43. Alternatively, the natural backfill which falls about the strip 10 may be used as the only means of backfilling the slit and securing the strip in position.

The installation apparatus 50 shown in FIG. 5 is similar to the installation apparatus 40, but the roller assembly 51 includes mounting frames 52 which hook over the dozer blade

53 and the strip material 54 is conveyed to the tyne 55

beneath the bulldozer 56 in order that distortion of the strip material 54 and thus frictional drag created upon passage of the strip material 54 through the tyne 55 as it feeds to and from the tyne 55 may be minimised. The tyne assembly 60 illustrated in Fig. 6 includes features which aim to minimise such frictional drag. For this purpose, the tyne assembly 60 includes a recessed mouth portion 61 to accommodate the distortion of the strip 62 as it twists from its horizontal attitude form which it feeds from the roller assembly upon which it is stored to a vertical attitude for passage through the slot downwardly and rearwardly inclined slot 63. Furthermore leading and trailing guide rollers 64 and 65 respectively are supported on the tyne adjacent the leading lower and trailing upper ends of the slot 63 to assist movement of the strip 62 therethrough. In addition a pair of elongate rollers 66 may be disposed in front of the mouth portion 61 to assist with the twisting of the strip 62 to a vertical attitude.

Other measures may be taken to reduce frictional drag upon passage of strip through tynes such as spraying a lubricant, which may be water, onto the strip as it is fed to the tyne ot directly into the strip feed slot in the tyne. Additionally the mounting drum for the strip may be arranged with its axis in a vertical plane and directly in front of or behind the strip feed slot so that no twisting of the strip is necessary prior to entry within the slot. The latter may be of constant cross section or it may vary in section to

accommodate the distortion in the strip as it passes through the slot. Furthermore the tyne may be solid and separate strip feed means may be utilized to feed the strip into the slit immediately behind the tyne. For example the slot could be replaced by an open slot associated with entry and exit guide roller means to maintain feed of the strip along the open slot and into the trench. In addition the strip storage drum may be driven to discharge strip at the ground speed of the dozer or the like. The present invention may also be utilized to stabilize dirt access roads, such as used in forrest plantations or the like, against runoff water damage. At present such roads are often provided with spaced earth "speed bump like" mounds at spaced intervals along inclined parts of the road to prevent runoff water from continuing along the road and causing erosion damage. These mounds are expensive to install and maintain.

According to present invention, as illustrated in Fig.

7, flexible strip material 70 is laid in trenches 71 cut across the road 72 at spaced intervals. The strip 70 is positioned to leave a portion 73 upstanding above the road

72. The strip 70 is also positioned obliquely to the road so as to ensure that runoff water is channelled to one side of the road and preferably at a rate which will prevent silt build up behind the strip 70. Alternatively the strip 70 may be sufficiently flexible that silt build up will eventually cause the strip to bend and lie along the ground whereupon

the next runoff will wash the silt away and cause the resilient strip to return to its upstanding position. Of course the strip is of such resilience that it may be driven over and flattened without damaging its ability to return to the upstanding position.

The strip 70 is suitably positioned with naturally compacted soil 73 on the upper side of the strip and with the backfill 74 at the lower side of the strip. In addition the strip may be utilized in conjunction with a further trench 75 which contains terrain stabilizing mesh 76 to stabilize the subsoil by growth of vegetation. The further trench could be of any suitable depth and of could be positioned adjacent to the trench 71 at either side thereof or be used independently il desired to provide soil stabilization. The strip 80 illustrated in Fig. 8 is in the form of a resilient plastics extrusion which will return to an upstanding position when driven over. The strip 80 includes an anchoring leg 81 formed with a return locating flange 82 and a hollow upstanding portion 83 provided with stiffening webs 84. The arrangement is provided to enhance the ability of the strip 80 to return to its upstanding attitude after deflection to a horizontal position as illustrated in dotted outline. The extrusion may be a composite extrusion utilizing different materials in different parts to achieve a cost effective product that will operate efficiently in use in an exposed location.

Figs. 9 and 10 illustrate further applications of the

present invention. Fig. 9 illustrates a river and associated floodplain. Typically the flood plain is regenerated by soil deposited during periods of flood. However with intensive farming of the flood plain it is common for floods to wash away valuable topsoil. According to this invention the strips 90 are arranged across the flood plain at right angles to the water flow with a portion upstanding above the ground and act to retain suspended solids in floodwater.

The strips 100 are placed in a beach in spaced parallel arrangement along the foreshore from the low water mark 101 to the high water mark 102. The upper edges of the strips 100 step upwardly from the low water mark 101 to the high water mark 102. As the beach height is not stable the upper edges are arranged at the desired height so that in use sand will build up behind the strips 100 or not be eroded below the strips 100. Thus a stable beach height should result. Alternatively the strips will determine the lowest height of the beach.

In a further embodiment of the invention as illustrated in Fig. 11 strips 110 are placed in spaced side by side relationship to form an open drain 111. Such drains may be utilized as drains from levees 112 confining an irrigation supply 113. The advantages are that the strips 110 form portable levee banks which may be readily used, stored and installed.

It will of course be realised that while the above has been given by way of illustrative example of this invention.

all such and other modifications and variations thereto as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of this invention as is defined in the appended claims.