CA1069332A - Method of establishing plants by pelleted seeds - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The present invention relates to a pellet useful for establishing plants on an area of land comprising sowing onto the bare soil, or onto existing herbage on the area of land, a pellet comprising at least one seed of at least one desired species of plant, nutrients sufficient to support the growth of the plant or plants until establishment, and from 10 to 30% by weight of a binding agent selected from clays and hydrophilic organic polymers selected from methyl cellulose, polyvinyl alcohols and alginates, said binding agent when sufficiently moist adhering to the soil to form a cohesive cake therewith, entrapping said seed or seeds; and wherein the nutrient materials are selected from materials that are available slowly to the seed. By the use of this invention desired species of pasture plants including grasses, clovers and lucerne can be established in areas where existing methods would prove too costly and would be precluded by unfavourable climatic and cultural conditions.

Description

This invention relates to a novel method of establishing pasture plants by over sowing on to bare soil or onto existing herbage.
Numerous problems exist in establishing pasture plants of high quality in different situations. These difficulties may arise from such as unfavourable climatic conditions, from inherently low fertility of the land and from competition by existing herbage.
Where land is of low inherent fertility fer~ilizers have to be applied in sufficiently large quantities to provide essential nutrlents for plants to develop successfully from seed.
Application of fertiliser is generally made by broadcasting and this encourages weed growth and growth of existing herbage equally with that of the desired pasture plant seedlings. If seed fails to germinate and establish then the fertilizer is wasted and the problem of seedling establishment at a later date is made more difficult. U~der such conditions the cost of pasture establishment are often economically prohibitive parti-cularly on land of low inherent fertility.
Z Once germination processes have been initiated they can-not be reversed and growth must proceed to the stage where roo~s have penetrated the soil and can draw the required moisture and nutrients therefrom. It frequently happens that sufficient water is present from dew or light rainfall to start germination in surface sown seed but that it is arrested by dryin~ winds and exposure to sunlight and the seedlings die. Fre~uently the over sown seed is held up by existing herbage or lies on coarsely structure open 50ils and fails to make close contact with the soil ~om which moisture can be obtained.
In somP situations where existing herbage is dense and of an

- 2 - ~

106~3;~2 undesirable type difficulty is exper;enced in introducing the desired species of pasture plant because of shading and competition for water. A normal pro-cedure would be to remove the existing herbage by ploughing and cultivation or overall treatment with weedkillers before sowing the pasture seed.
These methods are costly and where tractor drawn equipment is re-quired are limited by slope of the ground. They have the objection that a total loss of production occurs before the new pasture is ready for grazing.
Another difficulty is that where soils are deficient in nodule pro-ducing Rhi~obia bacteria nodulation of seedling of such as clover and lucerne is often unsuccessful even though inoculum is applied to the seed. With nitrogen fixation the un-nodulated seedlings fail to survive.
It is the object of this invention to provide an improved method of establishing desired species of pasture plants including grasses, clovers and lucerne in those situations where existing methods are limited by cost and by various unfavourable climatic and cultural conditions.
It is an object of this invention to provide an improved method of initiating germination of seed on marginal hill country or on any other pasture.
Accordingly this invention provides a method of producing a pelleted seed which comprises blending together in a moist state at least one seed of at least one desired plant species, nutrients sufficient to support the growth of the plant or plants, and from 10% to 30%~ based on the dry weight of the ingredients of a binding agent chosen from clays and hydrophilic or-ganic polymers selected from methyl cellulose, polyvinyl alcohols and al-ginates, said binding agent when sufficiently moist being capable of adhering to soil to form a cohesive ca~e therewith, entrapping said seed or seeds, forming the blended mixture into pellets, and drying the formed pellets, and wherein the nutrient materials are selected from materials that are available slowly to the seed.
It also provides a method of establishing ~lants on an area of land comprising sowing onto the bare soil, or onto existing herbage on the area of land, a pellet comprising at least one seed of at least one desired species of plant, nutrients sufficient to support the growth of the plant or plants until establishment, and from 10 to 30% by weight o a binding agent selected from clays and hydrophilic organic polymers selected from methyl cellulose, polyvinyl alcohols and alginates~ said binding agent when suffi-ciently moist adhering to the soil to form a cohesive cake therewith, en-trapping said seed or seeds, and wherein the nutrient materials are selected from materials that are available slowly to the seed.
In addition, the invention provides for the use of herbicides in the pellet in a form which serves to destroy or restrict growth of undesir-able vegetation in the vicinity of the pelle~ without unduly limiting growth of the desired species.
The pellet will preferably contain a plurality of seed of the same desired species although if two or more species are mutually compatible when grown in close association then such different species may be included in the same pellet.
Nutrient materials are provided in the pellet according to the fertility status of the soil in the area to be treated. Such nutrient materials are provided in a form that is compatible with the seed and also the germinating seed. One preferred requirement is that the materials are available slowly to the germinating seed and are thus generally of low solu-bility. The low solubility is also of value in reducing the loss of materials which may otherwise disappear through leaching eects. Suitable nutrient materials include phosphorus such as in the form of di-calcium phosphate, sulphur as calcium sulphate, calcium and magnesium as carbonates, potash as a glass frit with a soluble potash content, nitrogen preferably as a slow release type, of which there are available controlled condensation products of urea-formaldehyde, or crotonylide di-urea and trace elements such as molybdenum, boron and copper.
An important feature of this invention is that the nutrients are 106~ 32 used in such quantities and in such forms that they are released into solution in quantities that do not injure the seedling tissues. In addition further modification to the nutrients is provided for in this invention where Rhizobia bacteria are included in the coat for nodulation of such as clovers and lucerne since the bacteria are susceptible to injury from some forms of nutrients. Thus it has been found that use of soils containing a high propor-tion of peat or of peat wi~hout soil provides protection for the Rhizobia bacteria.
Inert materials such as silicate, talc, sawdust, paper pulp, peat and the like can be added in order to improve desirable physical character-istics of the granule such as stability and water holding capacity.
Wood pulp is a preferred additive as it has a high water absorp-tion capacity which improves the stability of the pellet when slumping under heavy rainfall.
Only small a~ounts of such additives are required, generally less than 10%, more preferably in range of 3-5% by weight of the pellet.
In addi~ion, there is provided in the pellet of this invention a binding agent, in an amount of from 10 to 30% by weight which, upon a suitably large fall of rain tends to disintegrate the granule from its normal form in-to a caked mass which slumps down into intimate contact with the soil sub-strate. Particular binding agent for this purpose have been found to be clays such as bentonite and kaolin but organic polymers such as methyl cellulose, polyvinyl alcohols or alginates can also be used.
The materials, therefore, act to bring the granular mass and embedd-ed seed into intimate contact with soil surface. In this way a moisture pathway is established through which, by capilliary action, moisture status adjacent to the seed is better maintained where it is available, together with nutrients in solution; to enable processes of germination and growth to be sustained. With subsequent rainfall the nutrient content of the granules is slowly leached into the soil and becomes available for further growth.
Preferably, such material is used in the weight percentage of between 10 and 30~ by weight of the pellet.

1~6~332 A further preferred additive to the pellets of this in~ention is a water soluble material of high molecular weight. The high molecular weight material such as polyethylene glycol establishes a negative osmotic potential which restricts imbibition of water by the seed and consequently, germination does not proceed.
Thus, for example, moisture from heavy dews or light falls of rain will not induce germination and consequently seedlings will not be exposed to desiccation following subsequent withdrawal of moisture by drying conditions.
However, following a sufficiently heavy fall of rain and consequent avail-ability of moisture in the soil, the high molecular weight material is dissolved from the immediate environment of the seed and germination will ensue under conditions conducive to continued growth.
The use of high molecular weight materials for controlling germina-tion by restricting imbibition of water by the seed also provides protection against possible injury from herbicides in solution when herbicides are employed in the pellet. After removal of the controlling material by the leaching effect of rainfall, the water soluble herbicide is itself sufficient-ly reved from the immediate vicinity of the seed so that the risk of injury to the germinating seedling is reduced.
The pellets can be produced by various means but generally employ blending of all the ingredients, wetting the ingredients, extruding or panning or rolling or otherwise forming into pellets and then drying the formed pellets. Alternatively, the pellets can be formed without seed and then the moist pellets can be rolled with seed in a drum or pan to cause the seed to become embedded on the surface of the pellets.
The pellets can be distributed by normal ground applicators or by aircraft. The number of pellets applied will depend on the requirements of the area to be treated. On low value marginal land, for example, an applica-tion rate of 100 kilograms per hectare with pellets of an average weight of one gram each would be an acceptable rate.
In some situations it may be desirable to incorporate pesticides and fungicides in the pellet.

~ 6 --la6~332 To exemplify one embodiment of this invention granules were pre-pared having the composition given in following Examples 1 and 2 with each pellet containing 5 grass seeds of the cockfoot species. Along with the pellets, bare untreated seed was applied at the same time to areas receiving a normal fertilizer trea~ment. The area treated was of low fertility at an altitude of 2000 ft. With the pelleted seed of ~he present invention, germination in excess of 70% was achieved and the growth of the seedling was far in excess of that normally expected. With the bare seeds, germination was less than 5% and those seedlings which did manage to become established were stunted to the extent that survival was doubtful.
EXAMPLE 1 PARTS BY _ IGHT

Superphosphate 30 ) reverted 40 Calcium carbonate 10) Gypsum (calcium sulphate) 10 Dolomite (magnesium carbonate 10 and 25 calciu~ carbonate 15) Bentonite 25 EXAMPLE 11 PARTS BY ~EIGHT
, Superphosphate 30 ) 40 ~r ) reverted Calcium carbonate 10 ) Gypsum (calciu~ sulphate) 10 Dolomite (magnesium carbonate 8 and calcium carbonate 12) 20 Bentonite 25 Crotonylide-di-urea 4.6 Ammonium nitrate 0.4 The following Example 111 exemplifies a pellet which is useful for establishing clover and/or lucerne.

Five seed per pellet innoculated with Rhizobium culture to give 40,000 bacteria per seed.

Rock phosphate 30 Dolomite ~magnesium carbonate 6 and calcium carbonate 9) 15 Peat soil (40% organic matter) 30 Bentonite 25 The following example illustrates the production of the pellets of this inven~iQn.
A mixture of lime reverted super phosphate (one of calcium carbon-ate to three of super phosphate), 2576 lbs, Dolomite 220 lb, Gypsum 440 lbs, Bentonite 1100 lbs was blended and milled to a mean particle size of 100 mesh BSS with 5 percent retained on a number 14 mesh BSS and 71 percent passing through a 200 mesh BSS. Water was added in a blender to bring total moisture within the range of 17.5 to 20.5 percent. 50 lbs of rye grass was blended into this mixture and extrusion commenced. The extruded pellets were tried by heated air in a tunnel type dryer. It was ~ound that an ambient drying temperature of 26 to 48 degrees C did not harm seed germination.
Mbisture content of the pe]lets were reduced to 9.8 percent in a drying time of 28 minutes. Production rates of up to 8,000 lbs per hour were achieved.
The dried product was screened to remove under size material which was avail-able for reprocessing.
The present invention therefore provides a novel method of establishing pasture which has particular applicability to marginal land.
Numerous advantages accrue from the use of the invention such as the saving in fertiliser achieved by concentrating the fertiliser around the seedlings instead of applying fertiliser to the whole of an area. A much smaller quantity of fertiliser is required for the first year of growth. Once the seedlings have become established after a period then overall,broadcasting of fertiliser becomes more economical. Other advantages in the use of the fertiliser in the pellets is that leaching and fixation of the nutrients in the soils goes on at a slower rate and furthermore, instead of encouraging -~growth from unwanted herbage over the whole area, the seedlings ensuing from 101t;~3;~3'~
the pellets are given preferential treatment and by their increased vigour of growth are better able to withstand competition. Another important advan-tage of the present invention is in the improved utilisation of seed.
Quantities of seed applied are frequently greatly in excess of the numbers of seedlings which are necessary for successful pasture establishment. By im-proving germination and reducing seedling mortality, reduction in seeding rates become possible. Furthermore, because of the improved growth, seedlings are in a better position to survive periods of drought and the severity of winter conditions, particularly effects of frost lift. Moreover, better utilisation can be secured by providing trace elements and plant protection chemicals such as fun~icides insecticides and herbicidal materials ~lerbi-cidal to other species) in the pelleted granule at economical levels.
Another important advantage is that this invention enables pasture species to be introduced without destruction to the existing sward. One exist-ing practice has been to employ herbicides to remove all vegetation on a pasture followed by seed application but this is wasteful of grazing and if over sowing is not successful, may leave some types of country open to erosion.
~urthermore, it is sometimes desired to introduce alternative pasture amongst existing pasture such as clover amongst grass or in reverse, grass amongst clover and it is possible according to this invention to include herbicides in the pellets capable of killing grasses adjacent to the pellets so that from pellets containing clover and/or lucerne seed establishment can be secured amongst the remaining non-destroyed grass. Alternatively, grass can be sowed into a clover pasture wherein the pelleted granule will contain grass seed together with a herbicide for the clover.
In addition, where seed such as clover and lucerne is to be used, Rhizobia bacteria can be incorporated into the pellets under conditions where-by survival of the Rhizobia and nodulation of the seedlings is enhanced.
So that according to this invention there is provided an improved method for establishing pasture on marginal or other land.

_ g _

Claims (18)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A method of establishing plants on an area of land comprising sowing onto the bare soil, or onto existing herbage on the area of land, a pellet comprising at least one seed of at least one desired species of plant, nutrients sufficient to support the growth of the plant or plants until establishment, and from 10 to 30% by weight of a binding agent selected from clays and hydrophilic organic polymers selected from methyl cellulose, polyvinyl alcohols and alginates, said binding agent when sufficiently moist adhering to the soil to form a cohesive cake therewith, entrapping said seed or seeds; and wherein the nutrient materials are selected from materials that are available slowly to the seed.

2. Method according to claim 1 wherein the nutrient materials are selected from dicalcium phospahte, calcium sulphate, calcium and magnesium carbonate, a glass frit with a soluble potash content, a controlled con-densation product of urea-formaldehyde, and trace elements.

3. Method according to claim 1 wherein the pellet additionally contains inert material to improve the stability and water holding capacity thereof.

4. Method according to claim 3 wherein the inert material is chosen from sawdust, paper pulp, wood pulp, and peat.

Method according to claim 3 wherein the inert material is wood pulp.

6. Method according to claim 5 wherein the wood pulp is present in an amount of less than 1% by weight of the total weight of the pellet.

7. Method according to claim 5 wherein the wood pulp is present in an amount of from 3-5% by weight of the total weight of the pellet.

8. Method according to claim 1 wherein the binding agent is bentonite.

9. A method of producing a pelleted seed which comprises blending together in a moist state at least one seed of at least one desired plant species, nutrients sufficient to support the growth of the plant or plants, and from 10% to 30%, based on the dry weight of the ingredients of a binding agent chosen from clays and hydrophilic organic polymers selected from methyl cellulose, polyvinyl alcohols and alginates, said binding agent when suffi-ciently moist being capable of adhering to soil to form a cohesive cake therewith, entrapping said seed or seeds, forming the blended mixture into pellets, and drying the formed pellets, and wherein the nutrient materials are selected from materials that are available slowly to the seed.

10. Method according to claim 9 wherein the pellets are formed by coat-ing the moistened nutrient, and binder, onto a seed or seeds.

11. Method according to claim 9 wherein the pellets are formed by blend-ing the moistened nutrients and binding agent, forming the thus-obtained blend into pellets, and blending with the moist pellets the seeds.

12. Method according to claim 9, 10 or 11 wherein the nutrient materials are selected from dicalcium phosphate, calcium sulphate, calcium and magnesium carbonate, a glass frit with a soluble potash content, a controlled condensa-tion product of urea-formaldehyde, and trace elements.

13. Method according to claim 9, 10 or 11 wherein an inert material to improve the stability and water holding capacity of the pellet is additionally included in the mixture of materials to be blended.

14. Method according to claim 9, 10 or 11 wherein an inert material to improve the stability and water holding capability of the pellet, chosen from sawdust, paper pulp, wood pulp, and peat, is additionally included in the mixture of materials to be blended.

15. Method according to claim 9, 10 or 11 wherein an inert material to improve the stability and water holding capability of the pellet, comprising wood pulp, is additionally included in the mixture of materials to be blended.

16. Method according to claim 9, 10 or 11 wherein an inert material to improve the stability and water holding capability of the pellet, comprising wood pulp in an amount of less than 10% by weight of the total weight of the pellet, is additionally included in the mixture of materials to be blended.

17. Method according to claim 9, 10 or 11 wherein an inert material to improve the stability and water holding capability of the pellet, comprising wood pulp in an amount of from 3% to 5% by weight of the total weight of the pellet, is additionally included in the mixture of materials to be blended.

18. Method according to claim 9, 10 or 11 wherein the binding agent is bentonite.