AU2418500A - Seeder for native grasses - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE PATENT SPECIFICATION

APPLICANT:

ADDRESS:

INVENTOR:

BRASSIL, John "Claremount", Cavan Rd, Yass, NSW, 2582 John Brassil r ADDRESS FOR

SERVICE:

Paul A Grant and Associates PO Box 60, Fisher, ACT, 2611 Seeder for Native Grasses INVENTION TITLE: ASSOCIATED PROVISIONAL APPLICATION: PP9725 filed 13 April, 1999 The invention is described in the following statement:- TITLE: Seeder for Native Grasses TECHNICAL FIELD This invention relates to methods and apparatus for use in planting the seeds of native Australian grasses and the like. Such seeds tend to be light in weight, elongate, delicate and/or hairy. It is particularly concerned with seeding methods and apparatus in which the seeds are applied via a liquid medium.

However, the seeder and methods of the invention are be applicable to seeds io other than native Australian grasses and are therefore not limited to this specific seeding application.

*.":BACKGROUND TO THE INVENTION Large scale planting of native Australian grasses and seeds is a means of 15 correcting land degradation and improving pastures in land where rainfall can be unpredictable and uncertain. Further, the use of native grasses in lieu of introduced species can provide a grass surface that is more durable, easier to maintain, and consumes less water for gardens, sporting facilities such as playing fields for ball sports, golf, and athletic pursuits. The use of native grasses in lieu of introduced species also helps to maintain the biodiversity in our environment and helps to preserve native flora varieties. However, Australian grasses such as Microlena (often called Weeping Grass) are most difficult to sow in a manner that achieves acceptable germination in regular rows, spacings or patterns. Microlena *o seeds are lightweight so that there may be as many as 200,000 seeds per kg., yet an individual Microlena seed might be a few millimetres long.

Conventional broadcaster-seeders are not satisfactory because the light-weight and elongate native grass seeds do not carry sufficiently and are prone to mechanical damage when being propelled. On the other hand, the elongate and hairy seeds cannot be satisfactorily fed into the tubes of conventional drills because of their tendency to clump together. Furthermore, the seeds of native Australian grasses cannot be satisfactorily fed through the conventional metering devices on drills designed for the hard compact seeds of many commercial cereals and oil crops. The fluted rollers, vaned rotors etc of these metering devices tend to break and damage the grass seeds, particularly if they cannot be fed into the metering device in a uniform manner and appropriately aligned with the direction of flow. It has been proposed (eg, US patent number 4,300,461 to Hodge) to entrain seeds to be planted in air and to deliver them to a groove cut in the soil by a tube. However, air entrainment of native grass seeds would be most difficult to achieve without severe clumping or physical damage. Similarly, while it has been proposed to deliver seed to a tine or coulter blade in air and then to io apply a water or fertiliser spray on the seed to lay it firmly in the soil eg, see Australian patent application number 68169/81 to Janke et al), such a technique pre-supposes that the seed can be fed to the tine in a uniform manner in the first place.

1is While the entrainment of seed in a liquid or paste-like matrix is known in the art and appears to offer advantages in the sowing of native grasses, problems were found when prior art systems were applied to the sowing of Australian native grasses and similar seeds in a liquid medium. Being elongate, delicate and hairy, many of these seeds are difficult to wet and suspend in paste without clumping.

Clumping not only prevents the seed from being distributed uniformly, but it can often cause the blockage of feeder tubes. On the other hand, vigorous stirring of the suspension leads to problems in feeding the seeds in an even manner into tubes or the like.

UK patent number 1,045,732 to Elliott, UK patent number 1,296,928 to Pilgrim et al disclose the use of a thick flowable nutrient matrix within which the seed is distributed and by which it is applied to the soil. Elliott employs a vane-type metering valve to control the flow of the matrix and seed mix but this method of metering would damage native grass seeds. Pilgrim et al achieve metering by allowing the slurry-like matrix mix to flow through a narrow slot onto a roller that applies it to the ground, but the narrow slot and this method of slurry application would not suit elongate grass seeds. These techniques are intended for minimum tillage methods where the matrix provides the initial moisture and nutrient for seed germination. They are superficially attractive for the sowing of native grasses, but it has been most difficult to obtain even distribution of native grass seed in matrices of this type in a simple and easy manner without damage to the seed. Experience also suggests that pump-driven extruders are likely to damage the elongate native grass seed.

US patent number 4,224,882 to Cruse, US patent number 3,230,570 to Flippen, US patent humber 3,442,221 to Phillips et al and UK patent number 1,045,732 to 1o NRDC all disclose apparatus for sowing seeds mixed in water wherein the mixture is fed to the ground (with or without the use of tines) through a resilient and a peristaltic-type pump that acts on the tube. For the rate of seed delivery to S. be substantially uniform over a tank-full, the ratio of seed to water must be very high. As no mixing or stirring means is disclosed, the need for substantially Is uniform seed delivery results in thick slurry being fed to the ground. Slurry of this character were difficult to form using native grass seeds for a variety of reasons.

.i First, being hairy, native grass seeds tend to wet slowly, trap air bubbles and float on the surface of water; second, once wet, they tend to settle out and to form clumps; third, if in a concentrated form, they will tend to clog the outlet from the tank to the tube and resist metering through a peristaltic-type pump.

The problem of even distribution of seeds from a liquid suspension was addressed in US patent number 4,119,242 to Jesty and US patent number 4,278,183 to Billington. These patents disclose robot-like apparatus for dispensing discrete objects, including seeds, suspended in liquids. However, being more suited to laboratory than to field conditions, these techniques are too costly for application to the sowing of native grasses on a broad-acre basis.

Finally, it is acknowledged that the technique of pre-geminating seeds using a wet nutrient matrix and then planting or spraying that matrix in or on soil is well known and has been applied to elongate exotic grass seeds in land stabilisation or reclaimation. For example, US patent number 4,750,438 to Johnson discloses a method in which seeds are soaked in water to expedite the uptake of water and germination of the grass seed, drained and then spread over an extended area to allow germination before being applied through a sprayer. Australian patent application number 39284/78 to Kelly et al discloses the use of a gel in which controlled pre-germination takes place before sowing or broadcasting of the seed and gel combination. Such pre-gemination techniques have not been found to work well with native Australian grasses and, at least in the latter case, there is still the problem of how to deliver the grass seed on soil in a uniform manner without damage.

OBJECTIVE OF THE INVENTION Accordingly, it is the objective of the present invention to provide a planting system that will overcome one or more of the disadvantages of the prior art, so that the system will be suitable for planting native Australian grasses or similar seeds.

More particularly, though not essentially, the present invention seeks to provide methods and apparatus that will allow the satisfactory entrainment of seed, *o°preferably at low concentrations, in a free-flowing aqueous medium for delivery by drilling methods.

OUTLINE OF THE INVENTION Accordingly, from one aspect, the present invention comprises a seeder including .a frame having a plurality of tines or coulters mounted thereon and adapted to be towed or supported behind a tractor, a tank for liquid mounted on the frame, stirrer means for agitating liquid within the tank, a plurality of tubes depending downwards from the tank to terminate in respective ones of said tines or blades, and hollow conical funnel-like interface means arranged between the bottom of the tank and the top of each tube for guiding liquid flow from the tank into the tubes. For convenience and without an intended limitation, the hollow conical interface means may be referred to as 'funnels' below.

It has been found that the use of such funnel-like interfaces permits flow of liquid containing native grass or similar elongate seeds into the tubes in a manner that minimises clumping and tangling of the seeds while promoting alignment of the seeds and even flow of the liquid mixture. It is thought that this is due to swirling motion induced in the liquid containing the seeds as it flows from the tank into the funnel and then into the tube.

If desired, such swirling motion may be encouraged or ensured by suitable design or arrangement of the stirring means. For example, a rotary bladed stirrer io having a substantially vertical axis may be arranged in line with and vertically above each funnel to induce a rotary motion in the liquid in the tank immediately above the funnel. Alternatively, and more conveniently, I have found that a large low-speed paddle-like stirrer with either a horizontal or a vertical axis of rotation and covering most if not all of the funnels can work satisfactorily. If desired, 15 portions of the blades of such stirrers may be angled, contoured or cut-away in such a manner as to produce eddies in the liquid in the tank which induce or S"promote the desired swirling motion of the liquid immediately above each funnel as the stirrer is rotated within the tank.

oooo The type of stirrer used will depend in part on the shape and orientation of the tank used and also on the particular requirements of the grass seed to be sown.

oooo 00•The rotational speed of the agitator is controlled to reduce damage to the seeds whilst still keeping them in suspension. The stirrer may be driven by any suitable means; for example, by a fixed-speed motor with suitable gearing or speedsetting, a variable-speed motor controlled from the seeder, a variable-speed motor controlled from the tractor or other towing vehicle, or (less desirably) by a drive train connecting the agitator(s) to the wheels of the seeder. A simple 12 or 24 volt motor powered by the electrical system of the tractor is suitable.

From another aspect, the invention comprises a seeder in which liquid containing grass seed is fed from a tank to tines or coulter blades via substantially unrestricted tubes that are arranged substantially vertically. While one or more of the metering devices known in the art may be employed, it has been found preferable to avoid the use of metering devices in the form of throttling valves or the like in the flow path. Such metering devices tend to promote the blocking of tubes in which native grass seeds and water flow.

Desirably, but not essentially, the rate of flow of the suspension through the tubing is determined largely by the inner diameter of the tubing itself. However, it is desirable to have some means of stopping the flow of the suspension while the seeder is being transported to the site where seeding is to take place, whilst io turning at the end of rows when seeding, or after seeding has been completed.

The seeds of many varieties of native grasses are difficult to harvest and expensive to buy, so it is important not to waste them. Some form of stop means is therefore desirable. A simple and effective valving method is to simply arrange to compress each tube by using a simple mechanical linkage that operates to s remove pressure on and open the tubes as soon as the tines are lowered to contact the ground and to compress and close the tubes as soon as the tines are raised again. Alternatively, a globe or other mechanical valve may be used as the stop means, and such a valve can also be operated by the aforementioned mechanical linkage. Preferably, the valves are arranged as close as possible to the outlets of the funnels to thereby minimise the accumulation of un-stirred seed S•above them.

oooo S.From another aspect, the invention involves the use of an entraining liquid that is predominantly water and which includes one or more wetting agents adapted to promote the rapid wetting of seed added to the water so that the entrainment of air within or on the seeds is minimised. It is desirable, however, that the wetting agent does not promote substantial foaming and that it does not in any way harm the seeds or the microflora of the grazing land to which the liquid is applied. I have found that macerated sheep manure contains sufficient surfactants to effect the desired degree of wetting and non-foaming. The surfactants arise it is supposed from the bile and microbial products contained within the manure.

From another aspect, the invention involves the use of means to increase the specific gravity of the water within which the grass seeds are entrained to the point were, after the seeds have become thoroughly wet, the rate at which they settle in the water under gravity is reduced. Again, I have found that, by adjustment of the amount of sheep manure added to the water, the settling rate of the grass seed can be greatly reduced. This has the effect of forming a substantially homogeneous suspension of grass seed in water that requires minium stirring or agitation to maintain homogeneity and that can contain low concentrations of grass seed. For example, the addition of 5-15% by volume of sheep manure to water will satisfactorily suspend as little as 1-5% by weight of seed to water. Much higher concentrations of both manure and seeds are possible, however, and may be preferred with some types of seeders.

It will be appreciated that the density of the solution can be varied according to 15 the seed type or variety and the type and character of the manure used. One convenient means of achieving all the desired features in a simple and effective way is to macerate dried sheep droppings and add them to water on an asneeded basis, preferably before adding the seeds. The quantity of the droppings can be varied to achieve the desired solution density. Animal droppings also contain the nutrient required to assist in the germination and subsequent seed growth, and they also tend to promote beneficial soil microflora. The manure solution can be prepared some time prior to seeding and the seed can be mixed into the solution just prior to seeding. Of course, other additives or nutrients can be added as desired and as is known in the art. The length of time prior to seeding that the seed and liquid mixture is allowed to stand can be varied to allow partial germination or thorough wetting of the seeds.

From another aspect, the invention comprises a method of planting Australian native grass seeds, or the like seeds, comprising the steps of adding the seeds to water containing at least one agent adapted to promote the wetting of the seed and at least one agent adapted to raise the density of the water to approximate that of the wet seed, mixing the liquid containing the seed to ensure substantially uniform distribution of the seed and causing the mixed liquid containing the seed to flow in a swirling or spiral motion into a tube through which the liquid and seed are fed for deposition on or in the ground.

DESCRIPTION OF EXAMPLES Having portrayed the nature of the present invention, particular examples will now be described with reference to the accompanying drawings. However, those skilled in the art will appreciate that many variations and modifications can be io made to the examples without departing from the scope of the invention as outlined above.

In the accompanying drawings: 5 Figure 1 is a sectional side elevation of the first example of the invention.

i Figure 2 is a sectioned rear elevation of the first example of the invention.

Figure 3 is a sectional side elevation of the second example of the

S

invention.

S. SqB Figure 4 is a sectional rear elevation of the second example of the invention.

o 25 Figure 5 is a sectional side elevation of the third example of the invention.

Figure 6 is a sectional rear elevation of the third example of the invention.

Referring to Figures 1 and 2, the first example comprises a seeder 10 having a main frame 12 supported by a pair of wheels 14 that are mounted on a sub-frame 16 which is pivotally supported from beneath main frame 12 about an axis indicated at 18. Main frame 12 includes atow bar 20 at its front end and has a series of tines 22 depending from it to engage the ground and form furrows therein when the seeder is towed behind a tractor (not shown). As in a conventional coulter-type seeder, there is a plurality of tines 22 arranged in staggered formation in a number of rows. However, for the sake of convenience, only one row of tines is shown in Figure 1. Main frame 12 can be raised or lowered with respect to the ground (to disengage or engage tines 22) by means of a hydraulic cylinder 24 acting between main frame 12 and sub-frame 16.

A pair of cylindrical liquid tanks 26 are supported on main frame 12 with their axes vertical, tanks 26 being adapted to hold the seed-containing slurry. A io paddle-like stirrer 28 is mounted within each tank 26 for rotation about the vertical axis of the tank, stirrer 28 having a lower set of blades 28a that sweep close to the bottom of tank 26, an upper set of blades 28b and an intermediate set of blades 28c. The stirrer 28 is driven by a motor 30, a belt or chain 32, a shaft 34 and suitable gearboxes 36 mounted on an upper sub-frame 37. Motor 30 can be 0 15 a stand-alone petrol engine, a hydraulic motor driven by fluid supplied from the tractor or an electric motor driven from the 12 or 24-volt supply of the tractor.

A plurality of funnel-like outlets 40 are formed in the bottom of each tank 26 and connected by flexible resilient hoses 42 to respective ones of the tines 22. For clarity, only one or two hoses 42 are shown in Figures 1 and 2. Enroute to the tines 22, all hoses 42 pass through guide holes formed in a guide bar 44 fixed to *5o* see or forming part of frame 12. A bent or cranked lever 46, attached to sub-frame 16 °at its lower end, is arranged so that its upper end carries a pair of transversely :extending pressure pads 48. When hydraulic cylinder 24 is operated to raise main-frame 12, sub-frame 16 and lever 46 are rotated with respect to frame 12 to bring the pressure pads 48 into forceful contact with the hoses 42 to compress them and cut off the flow of the seeding mixture to the coulter tines 22.

Conversely, when main-frame 12 is lowered, lever 46 is rotated to move pressure pads 48 away from hoses 42 and guide-bar 44 to allow the hoses to resiliently return to their normal shape and again permit flow of the seeded fluid to tines 22.

Of course, the tines 22 are only lowered, and the seeded mixture only flows, when seeding is to take place. When the seeder is being transported, the tines are raised and the flow of the liquid seeding mixture from tanks 26 is stopped.

As mentioned above, lower blades or paddles 28a of stirrer 28 pass close to the wide ends of funnel-like outlets 40. Preferably, blades 28a are angled, cut or otherwise formed so that they cause vortices in the vicinity of the funnel openings as blades 28a rotate. These vortices tend to promote circular or spiral flow of liquid and seed through the funnels. This ensures that the seeds in the liquid are aligned appropriately as they enter hoses 42.

io The seeder 100 of the second example is shown in Figures 3 and 4 and differs from the seeder 10 of the first example principally in the manner in which the tank and stirrers are arranged. Accordingly, the same reference numerals are used for the parts that are the same as those of the first example.

15 In the second example, a long transversely mounted trough-like tank 102 is mounted on main-frame 12 and is fitted with a horizontally disposed paddle-like stirrer 104 arranged to rotate on horizontal a shaft 106 that is driven by motor and belt or chain 32. Stirrer 104 includes a plurality of slat-like blades 108 mounted on spoke-like supports 110. Again, a plurality of funnel like outlets 20 are fitted into the bottom of tank 102 and connected to hoses 42 that connect to *..*tines 22 so that liquid therefrom is discharged immediately behind the tines when seeder 100 is in use. As before, hoses 42 are clamped-off by pressure pads 48 cranked lever 46 and acting on guide-bar 44. In Figures 3 and 4, however, hydraulic cylinder 24 is not shown for the sake of clarity.

S In operation, the main frame 12 is raised to lift tines 22 and block hoses 42, the tanks (26 or 102) are filled with water and the stirrers (28 or 104) are set in motion. Pulverised or macerated sheep manure is added to the water and stirred until substantially dissolved and/or suspended. After which, the desired amount of seed is added while stirring is maintained. When all the seed has been wetted and distributed evenly in the water mixture, the seeder is transported to the location to be planted and towed behind a tractor when the tines 22 are lowered 12 and the hoses 42 unclamped. Whereupon, the seeded liquid enters into the funnels 40 with a swirling motion and flows down the tubes under gravity to the tines 22 where it is placed into the furrows formed by the tines.

The seeder 200 of the third example is shown in Figures 5 and 6 and differs from the seeder 100 of the second example principally in the manner in which the seeder is attached to the tractor (not shown) and in the manner in which the flow of liquid and seed from the tank is stopped when the seeder is raised from the ground. Accordingly, the same reference numerals are used for the parts that are io the same as those of the second example.

In the third example, a long transversely mounted trough-like tank 102 is mounted on main-frame 12 and is fitted with a stirrer 104 and funnels 40 as in the second example, but frame 12 is adapted to be mounted on the standard three-point o:1: is linkage on the back of a tractor. A central upper eye 202 is adapted to be fitted to the central link of the three-point linkage and two lower eyes 204, one on each side of frame 12, are adapted to take the respective lower link arms of the threepoint linkage. As before, a sub-frame 16 having wheels 14 is pivotally mounted via joint 18 on the lower part of frame 12, the wheels serving to set the height of S 20 the frame from the ground and, thus, the depth to which tines or blades 22 can penetrate the ground.

In this example, a globe valve 206 is fitted to the bottom of each funnel 40 and is operated by a lever 208, lever 208 being pivotally connected to a link arm 210 25 that is, in turn, pivotally connected to an operating arm 212, which is fixed to subframe 16 so as to pivot therewith about pivot 18. In the position shown in Figure frame 12, sub-frame 16 is shown in the raised position so that wheels 14 hang down from the frame below the level of tines 22. In this position, valve levers 208 are substantially horizontal and valves 206 are closed. When frame 12 is lowered to the operating position, wheels 14 contact the ground (not shown) and pivot sub-frame 16 clockwise about pivot point 18. This causes the lower end 210a of link arm 210 to swing forwards and upper end 210b of link arm 210 to swing 13 downwards, forcing valve lever 208 to swing anti-clockwise through about 900 so that it is approximately vertical, turning valve 206 from 'off' to 'on'.

Referring more specifically to Figure 6, it will be seen that there are three operating arms across the width of seeder 200, the free ends of which are connected together by a horizontal bar 214, upon which link arms 210 are pivoted. For the sake of clarity only one link arm 210 is shown in Figure 6.

The use of 'on-off' non-throttling globe valves 206 in the third example have the io advantage that they can be located very close to funnels 40 and are even less prone to blocking than the pinch 'valves' of the second example.

While three particular examples have been described, those skilled in the art will appreciated that many alterations and additions thereto can be made without 15 departing from the scope of the invention as defined by the following claims.

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