WO1994003057A1

WO1994003057A1 - Composition and container for controlling plant root growth and method for using same

Info

Publication number: WO1994003057A1
Application number: PCT/US1992/006349
Authority: WO
Inventors: Mark Allen Crawford; Hamid Ullah
Original assignee: Griffin Corp
Current assignee: Griffin Corp
Priority date: 1992-07-31
Filing date: 1992-07-31
Publication date: 1994-02-17
Anticipated expiration: 1995-01-31
Also published as: JPH06511499A

Abstract

A composition for controlling plant root growth comprising a source of cupric ions dispersed in a film-forming matrix, the composition being substantially free of titanium. A plant container with a film of such composition on the interior surface thereof controls plant root growth. The source of cupric ions preferably comprises copper hydroxide and the matrix preferably includes latex. The composition may further comprise a micronutrient such as iron. The composition may also include a filler, water, a humectant, a dispersant, a surfactant, a thickening agent, an anti-foam agent, and a preservative. A method of controlling plant root system growth comprises the step of storing soil and the plant root system in a container comprising an interior surface and a film covering at least a portion of the interior surface, the film being formed from the foregoing composition.

Description

COMPOSITION AND CONTAINER FOR

CONTROLLING PLANT ROOT GROWTH AND METHOD FOR USING SAME

Technical Field This invention relates to the control of plant root growth, and more particularly relates to the use of copper to control plant root growth.

Background of the Invention Cultivated plants are often propagated by initially germinating seeds or rooting cuttings at one site and then transplanting the seedlings or transplants to another site. For example, plants can be initially grown at a nursery and then transplanted by the customer to a permanent site. However, transplanting can be harmful to a plant. One problem with transplanting is that the plant root system can be damaged when the plant is removed from the initial site. Plants with damaged root systems often undergo transplant shock which can slow plant growth and, in some instances, kill the plant. To reduce transplant shock, plants are initially grown in containers and then transplanted. Removing a plant from its container is less likely to damage the plant's root system than digging the plant out of the ground. A variety of plants, such as vegetables, trees, shrubs, and the like, are initially grown in containers and then transplanted. However, transplanting plants from containers still presents some problems. One problem occurs when plants such as vegetables are grown in 5 containers placed close to one another. The root growth of each plant can extend beyond its container and become entangled with the roots of adjacent plants. When the containers are separated and the plants are removed from the containers for transplanting, the root

10 systems are damaged and the plants can undergo transplant shock. Another problem with plants grown in containers is that the container prevents the root system of the plant from growing in a natural pattern. In a natural environment, plant root systems extend

15 relatively far away from the plant in the lateral and vertical directions for plant stability and maximum nutritional intake. In a container, the area of growth of the root system is limited and the roots are forced to turn at the container walls and grow into a tangled root

20 ball which takes the shape of the container.

To control root growth in a plant container, chemical root pruning has been used. Chemical root pruning involves the use of chemicals such as copper compounds to stop root growth. For example, a

25 mixture of commercial acrylic latex paint and copper carbonate or copper hydroxide effectively controls root growth when used to coat the interior of a plant container. The copper in the latex paint is adsorbed by the roots as the roots approach the sides of the container

30 and stops the growth of the roots. The root systems then branch behind the point of root growth inhibition. The plant root systems tend to maintain a more natural growth pattern although the growth of the root system is forshortened. When the plants are transplanted, the root

35 systems resume normal growth. According to the Container Tree Nursery Manual, vol. 2, Containers and Growing Media (Dec. 1990) published by the United States Department of Agriculture, typical copper coatings for plant containers include from about 60 to about 200 grams of copper compound, such as copper carbonate, per liter of commercial latex paint. The amount of copper in the coating which is effective depends partly on the type of plant to be grown in the container. It is commercially desirable to use an amount of copper compound in the lower portion of the foregoing range or perhaps even less to reduce the cost of the coating. Therefore, there is a need for a composition that consistently controls root growth for a variety of plants and is economical.

Summary of the Invention

The present invention solves the above described problems in the prior art by providing a composition for controlling plant root growth comprising a source of cupric ions dispersed in a film-forming matrix, the composition being substantially free of titanium. As discussed above, copper compositions for plant root growth control are made with commercial latex Ό aint as the coating matrix. Typically, commercial latex paint includes substantial quantities of titanium dioxide.

Titanium and cupric ions, along with other metallic ions in the container coating compete for ion adsorption sites on plant roots. Therefore, titanium, by occupying adsorption sites on plant roots, inhibits the ability of the copper in prior art root control coatings from performing as effectively as possible to control root growth. The composition of the present invention which is substantially free of titanium makes more effective use of copper to control plant root growth. More particularly, the composition of the present invention may further comprise a metallic micronutrient dispersed in the film-forming matrix. Suitable metallic micronutrients include iron, boron, zinc, manganese, 5 molybdenum, and magnesium, and the like. Such micronutrients also compete with cupric ions and other metallic ions for adsorption sites on plant roots. Without the presence of titanium in the composition of the present invention, the metallic micronutrients are

10 more effective. More particularly, the composition of the present invention may further comprise iron oxide which is a source of micronutrient iron ions.

Suitable sources of cupric ions include copper hydroxide, copper carbonate, copper sulphate, tri-basic

15 copper sulphate, and cuprous oxide. Preferably , the source of cupric ions is present in an amount from about 2 to about 20 percent by weight of the composition.

More particularly, the composition of the present invention includes a film forming agent such as latex as

20 part of the matrix. The latex is preferably present in an amount from about 2 percent to about 30 percent by weight of the composition. Still more particularly, the matrix further comprises a filler and water. Still more particularly, the matrix may further comprise a

25 humectant, a dispersant, a surfactant, a thickening agent, an anti-foam agent and a preservative. It should be understood however that the composition of the present invention may also include other components such as coalescing agents, cosolvents, and pesticidal compounds.

30 According to another aspect of the present invention, there is provided a container for holding the root system of a plant and soil comprising an interior surface and a film covering at least a portion of the interior surface of the container, the film being formed

35 from the above composition of the present invention such that the film comprises a source of cupric ions dispersed in a matrix and is substantially free of titanium. The film on the interior surface of the container preferably includes the source of cupric ions in an amount from about 3 percent to about 30 percent by weight of the film, elastomer in an amount from about 10 percent to about 65 percent by weight of the film, and filler in an amount from about 20 percent to about 70 percent by weight of the film. More particularly, the film may further comprise a metallic micronutrient in an amount from about 1 percent to about 8 percent of the film.

According to yet another aspect of the present invention, there is provided a method for controlling plant root system growth comprising the step of storing soil and the plant root system in the above-described container of the present invention. The method of the present invention is suitable for controlling the root growth of a variety of plants including trees, shrubs, vegetables, and grains such as rice.

Accordingly, an object of the present invention is to provide for improved control of root growth in containers.

Another object of the present invention is to provide a more economical and effective control of root growth in plant containers.

Still another object of the present invention is to provide an improved plant container.

Yet another object of the present invention is to provide an improved method for propagating and transplanting plants.

Other objects, features and advantages of the present invention will become apparent from the following detailed description and claims. Detailed Description of Preferred Embodiments

Generally described, the composition of the present invention comprises a source of cupric ions 5 dispersed in film-forming matrix, the composition being substantially free of titanium. The composition of the present invention may be used to coat the interior surface of plant containers to control the root growth of plants in the containers. The cupric ions from the

10 composition of the present invention are adsorbed onto ion adsorption sites of plant roots and stop growth of the plant roots short of the container walls. Without titanium in the film forming matrix, more ion adsorption sites of plant roots are available for the

15 cupric ions in the present invention and more effective use of the cupric ions is made.

The source of cupric ions is preferably cupric hydroxide but other suitable sources include copper carbonate, copper sulphate, tri-basic copper sulphate,

20 and cuprous oxide. The composition of the present invention preferably includes the source of cupric ions in an amount from about 2 percent to about 20 percent by weight of the composition. After the composition of the present invention has been applied to the interior of

25 a plant container to form a film, the film preferably comprises from about 3 percent to about 30 percent by weight of the source of cupric ions.

The matrix of the present invention preferably comprises a film-forming agent which is a preferably a

30 latex such as acrylic latex, vinyl acetate latex, or styrene-butadiene latex. Suitable film-form agents also include saponified wood resin emulsions, polyvinyl pyrrolidone, and polyvinyl acetate. The film-forming agent is preferably present in the composition of the

35 present invention in an amount from about 5 percent to about 40 percent by weight of the composition. The film-forming agent functions as a binder upon drying of the composition. When the composition of the present invention forms a film in the interior surface of a plant container, the solid components of the film-forming agent, such as the elastomer in latex is present in the film in an amount from about 10 percent to about 65 percent by weight of the film.

The composition of the present invention may also include a filler which imparts porosity and structure to the resulting dried film. Suitable fillers include calcium carbonate, melamine resin compounds, various types of clays, amorphous silica, precipitated silica, or diatomaceous earth. In the composition of the present invention, the filler is preferably present in an amount from about 15 percent to about 50 percent by weight of the composition. In the dried film, the filler is preferably present in an amount from about 20 percent to about 70 percent by weight of the film. The composition of the present invention may further comprise a metallic micronutrient dispersed in the matrix. Metallic micronutrients also compete for ion adsorption sites on plant roots and the composition of the present invention, being substantially free of titanium, makes more effective use of such metallic micronutrients. Suitable metallic micronutrients include iron, boron, zinc, manganese, molybdenum, and magnesium, and the like. More particularly, the composition of the present invention may include iron oxide which serves both as a colorant and a source of iron as a micronutrient. Iron aids in preventing chlorosis in plants. The metallic micronutrient is preferably present in an amount from about 0.5 to about 5 percent of the composition. In the dried film, the metallic micronutrient is preferably present in an amount from about 1 percent to about 8 percent by weight of the film.

The composition of the present invention may also include a humectant which imparts freeze-thaw stability to the composition and functions as a processing aide or co-solvent. Suitable humectants include propylene glycol, ethylene glycol, and diethylene glycol, and the like. In the composition of the present invention, the humectant is peferably present in an amount up to about 10 percent by weight of the composition.

The composition of the present invention may also include dispersants for enhancing shelf life of the composition by stabilizing the dispersant of solids in the composition. Suitable dispersants include polyelectrolytes, lignin sulfonates, and naphthalene derivatives, or the like. In the composition of the present invention, the dispersant is preferably present in an amount up to about 4 percent by weight.

The composition of the present invention may also include a surfactant for enhancing the function of the dispersant and lowering the surface tension of the composition, thereby providing improved coverage and tenacity on the plant container surface. Suitable surfactants include phosphate esters, block copolymers, sulfosuccinates, salts of sulfonated alcohols, ethoxylated alcohols, and tetramethyl decyne diol, or the like. Still further, the composition of the present invention may include a thickening agent for increased viscosity and enhanced storage stability. Suitable thickening agents include xanthan gum, polysacharide gum, cellulose derivatives, polymeric thickeners, and clay, or the like. The composition of the present invention may further include an antifoam agent to reduce foam generation during manufacture. Suitable antifoam agents includes oils, dimethyl silicone, and tetramethyl dycene diol, or the like. The composition of the present invention may still further include a preservative for extending the shelf life of the product by eliminating spoilage due to microbial degradation. Suitable preservatives include l,2-benzisothiazolin-3-one, and formaldehyde, or the like. In the composition of the present invention, the surfactant is preferably present in an amount up to about 4 percent by weight of the composition, the thickening agent is preferably present in an amount up to about 3 percent by weight of the composition, the antifoam agent preferably present in an amount up to about 4 percent by weight of the composition, and the preservative is peferably present in an amount up to about 2 percent by weight of the composition. Yet further still, the composition of the present invention may also include other additives such as co- solvents, other pesticidal compounds, or coalescing agents. Suitable co-solvents include methanol, isopropyl alcohol, and the like, which reduce drying time by flashing off the water in the composition. Suitable pesticidal compounds include soil sterilants, insecticides, and systemic fungicides, or the like. Suitable coalescing agents include alcohol esters, amminated products, or butyl cellusolve materials which also reduced drying time of the composition. Lastly, the composition of the present invention can be formulated with up to about 40 percent by weight water.

The present invention is further illustrated by the following examples which show embodiments designed to teach those of ordinary skill in the art the manner of carrying out the present invention.

The formulations for Examples 1-6 are shown in Table 1 as Ex. 1-6. GAFAC RS 610 is a dispersant comprising a phosphate ester of a fatty alcohol and is available from Rhome-Poulenc of Cranburry, New Jersey. TAMOL 850 is a dispersant comprising a polyelectrolyte such as a sodium or potassium salt of a polymeric carboxylic acid and is available from Rohm and Haas of Philidelphia, Pennslyvania; PROXEL GXL is a preservative available from ICI Chemical of Wilmington, Delaware. The copper hyroxide is a technical grade comprising approximately 57.5 percent elemental copper. MAPICO is a black iron oxide available from Columbian Chemicals Company from

Atlanta, Georgia. ATOMITE is a filler comprising calcium carbonate and is available from ECC America of Sylacauga, Alabama. KELZAN AR is a thickening agent comprising a polysacharide and is available from KELCO of San Diego, California. BB 748 is an anti¬ foam agent available from Witco Corporation of New York, N.Y. UCAR 413 is an acrylic latex binder agent available from Union Carbide of of Danbury, Connecticut and has a solid conent of about 47 percent. Another suitable latex is UCAR 429 also available from Union Carbide. The water, propylene glycol, GAFAC RS 610,

TAMOL 850 and PROXEL GXL were mixed in a cowles mixer. While the foregoing mixture was mixing, the copper hydroxide, MAPICO iron oxide, ATOMITE and KELZAN AR were added to the cowles mixer and mixing was continued for 15 minutes. The

BB 748 and UCAR 413 were then added to the mix and shearing was continued for 30 additional minutes.

The formulations from Examples 1-6 were evaluated for root control effectiveness. The formulations were painted on one-quart plastic pots (4.5 in, diameter x 4.5 in. height). After drying, the pots were filled with a peat moss-based soilless mix and seeded with field corn. The plants were maintained for 30 days at which time the plants were subjectively evaluated for any abnormal growth characteristics (i.e. chlorosis, necrosis, stunting) and root control was subjectively rated using a 0-100 percent scale where 0 percent equals no root control and 100 percent equals 100 percent root control. The results of the root control experiments are also shown Table 1.

For comparison, a composition comprising cupric hydroxide dispersed in Sears white latex paint was evaluated for root control using the root control test described above. The cupric hydroxide was present in an amount of 100 grams per liter of the paint. Examples 1-5 each had a greater percentage of root control than the Sears paint preparation.

The foregoing description only relates to a particular embodiment of the present invention, and numerous changes may be made therein without departing from the spirit and scope of the invention as defined in the following claims.

Claims

1. A composition for controlling plant root growth comprising a source of cupric ions dispersed in a film forming matrix, the composition being substantially free of titanium.

2. A composition as in claim 1 further comprising a metallic micronutrient dispersed in the matrix.

3. A composition as in claim 2 wherein the metallic micronutrient is selected from the group consisting of iron, boron, zinc, manganese, molybdenum, and magnesium.

4. A composition as in claim 1 further comprising iron oxide.

5. A composition as in claim 1 wherein the source of cupric ions comprises copper hydroxide.

6. A composition as in claim 1 wherein the source of cupric ions is present in an amount from about

2% to about 20% by weight of the composition.

7. A composition as in claim 1 wherein the matrix comprises latex.

8. A composition as in claim 7 wherein the latex is present in an amount from about 5% to about 40% by weight of the composition.

9. A composition as in claim 6 wherein the matrix comprises latex.

10. A composition as in claim 1 wherein the 5 matrix comprises latex and a filler.

11. A composition as in claim 1 wherein the matrix comprises latex, a filler, and water.

10 12. A composition as in claim 1 wherein the matrix comprises latex, a filler, and water, the source of cupric ions being present in an amount from about 2% to about 20% by weight of the composition, the latex being present in an amount from about 5% to about

15 40% by weight of the composition, the filler being present in an amount from about 15% to about 50% by weight of the composition, and the water being present in an amount from about 0% to about 40% by weight of the composition.

20

13. A composition as in claim 12 further comprising a metallic micronutrient dispersed in the matrix, the metallic micronutrient being present in an amount from about 0.5% to about 5%. of the

25 composition.

14. A composition as in claim 1 wherein the matrix comprises latex, a filler, water, a humectant, a dispersant, a surfactant, a thickening agent, an antifoam

30 agent, and a preservative.

15. A composition as in claim 1 wherein the matrix comprises latex, a filler, water, a humectant, a dispersant, a surfactant, a thickening agent, an antifoam agent, and a preservative the source of cupric ions being present in an amount from about 2% to about 20% by weight of the composition, the latex being present in an amount from about 5% to about 40% by weig. )f the composition, the filler being present in an amount from about 15% to about 50% by weight of the composition, the water being present in an amount up to about 40% by weight of the composition, the humectant being present in an amount up to about 10% by weight of the composition, the dispersant being present in an amount up to about 4% by weight of the composition, the surfactant being present in an amount up to about 4% by weight of the composition, the thickening agent being present in an amount up to about 3% by weight of the composition, the antifoam agent being present in an amount up to about 4% by weight of the composition, and the preservative being present in an amount up to about 2% by weight of the composition.

16. A container for holding the root system of a plant and soil comprising an interior surface and a film covering at least a portion of the interior surface, the film comprising a source of cupric ions dispersed in a matrix and being substantially free of titanium.

17. A container as in claim 16 wherein the film further comprises a metallic micronutrient dispersed in the matrix.

18. A container as in claim 17 wherein the metallic micronutrient is selected from the group consisting of iron, boron, zinc, manganese, molybdenum, and magnesium.

5

19. A container as in claim 16 wherein the film further comprises iron oxide.

20. A container as in claim 16 wherein the 10 source of cupric ions comprises copper hydroxide.

21. A container as in claim 16 wherein the source of cupric ions is present in an amount from about 3% to about 30% by weight of the film.

15

22. A container as in claim 16 wherein the matrix comprises elastomer.

23. A container as in claim 22 wherein the 20 elastomer is present in an amount from about 5% to about 65% by weight of the film.

24. A container as in claim 21 wherein the matrix comprises elastomer.

25

25. A container as in claim 16 wherein the matrix comprises elastomer and a filler.

26. A container as in claim 16 wherein the matrix comprises elastomer, and a filler, the source of cupric ions being present in an amount from about 3% to about 30% by weight of the film, the elastomer being present in an amount from about 10% to about 65% by weight of the film, and the filler being present in an amount from about 20% to about 70% by weight of the film.

27. A container as in claim 26 further comprising a metallic micronutrient dispersed in the matrix, the metallic micronutrient being present in an amount fro- about 1% to about 8% of the film.

28. A method of controlling plant root system growth comprising the step of storing soil and the plant root system in a container comprising an interior surface and a film covering at least a portion of the interior surface, the film comprising a source of cupric ions dispersed in a matrix and being substantially free of titanium.

29. A method as in claim 28 wherein the film further comprises a metallic micronutrient dispersed in the matrix.

30. A method as in claim 29 wherein the metallic micronutrient is selected from the group consisting of iron, boron, zinc, manganese, molybdenum, and magnesium.

31. A method as in claim 28 wherein the film further comprises iron oxide.

32. A method as in claim 28 wherein the source of cupric ions comprises copper hydroxide.

33. A method as in claim 28 wherein the source of cupric ions is present in an amount from about 3% to about 30% by weight of the film.

34. A method as in claim 28 wherein the matrix comprises elastomer.

10

35. A method as in claim 34 wherein the elastomer is present in an amount from about 10% to about 65% by weight of the film.

15 36. A method as in claim 33 wherein the matrix comprises elastomer.

37. A method as in claim 28 wherein the matrix comprises elastomer and a filler.

20

38. A method as in claim 28 wherein the matrix comprises elastomer, and a filler, the source of cupric ions being present in an amount from about 3% to about 30% by weight of the film, the elastomer being present

25 in an amount from about 10% to about 65% by weight of the film, and the filler being present in an amount from about 20% to about 70% by weight of the film.

39. A method as in claim 38 further comprising 30 a metallic micronutrient dispersed in the matrix, the metallic micronutrient being present in an amount from about 1% to about 8% of the film.

40. A method as in claim 28 wherein the plant 35 is a vegetable.

41. A method as in claim 28 wherein the plant is rice.