Plant husbandry – Mulching
Reexamination Certificate
2001-03-19
2001-10-30
Carone, Michael J. (Department: 3643)
Plant husbandry
Mulching
Reexamination Certificate
active
06308455
ABSTRACT:
FIELD OF INVENTION
This invention relates to agricultural mulch, specifically to a method and machine for changing or renewing the exposed surface of synthetic agricultural mulch in order to enhance agricultural quality and yield.
BRIEF DESCRIPTION OF THE PRIOR ART
Agricultural plastic film mulch is a layer of plastic film placed on the soil near or surrounding seeds or crops to enhance growth and yield. Farmers have long used a variety of mulches including straw and wood chips, biodegradable paper, and plastic film. Mulches in general can reduce weed growth by restricting light and oxygen, and protect seeds from foraging animals. Plastic film mulch is in widespread use in the truck farming and nursery industries and improves crop performance in a number of ways. It can help to maintain soil temperature at levels that are conducive to good seed germination and plant growth by absorbing sunlight and helping to trap heat in the soil. It can also aid in concentrating natural or applied moisture in seedbeds and near the roots of growing plants. Agricultural plastic mulch has been developed with a coating of reflective metal (“metalized plastic”) that reflects sunlight onto the plant, vine, or tree, resulting in increased growth and yield.
Plastic films in widespread use for agricultural plastic film mulch are generally polyolefin family plastics (polyethylene, polypropylene, or polybutylene) of high or ultra-high molecular weight, commonly ranging in thickness from 0.5 to 6 mil thickness. Experience in use has shown that these films are usable for one to three seasons, depending on number of plantings, damage due to crop maintenance, traffic, UV degradation and the like. Removal of used film may be difficult, requiring extensive manual labor. Disposal of used film can also be costly due to traces of pesticides and fertilizer applied to the crops.
Recent research from major universities indicates that it is desirable to change the color and light absorption/reflective characteristics of the mulch film during the growing season to enhance plant growth, achieve better fruit color, change ripening characteristics, and reduce certain insect pests. U.S. Pat. Nos. 4,920,692, 5,138,792, 5,644,998, 5,729,929, and 5,846,661 describe various plastic films with special characteristics for use as agricultural mulch. For example, a particular variety of tomato may show better yield with red colored mulch than with other colors. A particular variety of beans may show best performance with yellow mulch. Certain insect pests and insect borne diseases may be significantly reduced with the application of metalized film mulch. Early growth in areas with shorter growing seasons may be improved by the use of black or transparent film mulch for maximum heat absorption. Later in the growing season, it may be desirable to change the color and light absorption characteristics of the initial mulch to those of a different plastic material such as metalized film to obtain the benefits of the color-reflective plastic mulch. In some climates, different crops with different mulch requirements may be planted in the same field in one growing season. Mulch selection is a compromise between the requirements of the two crops, or costly replacement must be performed during the middle of the season.
Prior art has not adequately addressed the need to change plastic film mulch color and light absorption characteristics. Renewal or changing color of existing film mulches is currently accomplished by removal and replacement. The problems with removal and replacement are that it results in an expense for removal and disposal, damages the plastic mulch so it cannot be reused, and potentially damages the crop itself U.S. Pat. No. 5,452,652 (Thomas W. Brooks, Captiva, Fla., Sep. 26, 1995) describes a machine for removing and baling plastic mulch from agricultural fields. U.S. Pat. No. 4,796,711 (Ralph W. Chrysler, Alva, Fla., Jan. 10, 1989) describes a machine for removing plastic film from raised plant beds.
Two layer mulches have been used, with the top layer designed to disintegrate over time, exposing the bottom layer. Because of the many variables affecting degradation of the top layer and exposure of the bottom layer such as weather and durability of the top layer, proper control of the process has not been achieved. The farmer cannot control when the bottom layer will be exposed and the land is also littered with remnants of the deteriorated top layer. Various machinery for applying plastic film to furrows, earth surfaces and the like is described in U.S. Pat. Nos. 5,536,116, 4,888,913, 4,513,530, 4,285,161, and 3,559,599.
Yet another method used is to install one layer of plastic mulch and to coat its surface later with a liquid such as paint to produce a different color or reflective quality. The problem with this method, however, is that the key element of reflective plastic is its metalized surface, and such metalization cannot be done in the field. Therefore, this method also does not adequately address the problem of how to change the exposed surface of mulch. U.S. Pat. No. 4,932,156 describes a method for controlling the color of vegetable fiber mulch for retarding the fading and restoring the color of the mulch through spray application of a color control solution.
SUMMARY OF THE INVENTION
This invention is directed to the method and machine for applying one or more strips of plastic film to an existing agricultural plastic film mulch substrate that can be attached to a standard farm tractor or drawn by a man or animal. The object of the invention is to provide a method and machine that easily allows the user to attach the new agricultural plastic film to the existing mulch in locations and configurations that are user adjustable to accommodate varying field conditions and crop requirements to accomplish a change in color and light absorption characteristics, and renewal of the structural integrity of the plastic film substrate through the added integrity of the applied film layer. This invention can also be drawn behind an agricultural plastic mulch laying machine to laminate plastic to the new mulch at the time the mulch is laid to construct a multi-colored, multi-characteristic mulch installation.
The field-laminating machine consists of a 3-point hitch mounted carrier frame with height adjustable wheels carrying a tool bar upon which are mounted one or more laminator assemblies. The frame also carries a radial blade pressure blower driven from tractor. The blower provides a pressurized air supply to high velocity outlet nozzles attached to the frame for the purpose of removing soil and other debris from the surface of the plastic mulch.
The laminator assembly consists of the film stock roll carrier, one or more guide rolls, and a press roll. The film stock roll carrier is used to hold the roll of film stock, and to allow its free rotation and unwinding. The guide rolls direct the film web to the press roll at the desired angle of application. The press roll rolls along the surface of the ground on top of the film layer being applied and exerts pressure on both new and existing layers of film. The laminator assembly is designed to be removable from the carrier frame so that an agricultural worker or draft animal can draw it where conditions preclude the use of a tractor.
The machine is adaptable to allow the use of adhesive, heat welding/fusing or mechanical fastening to secure the lamination. The machine and method can be used with any flexible plastic film that can be attached to another film by mechanical, adhesive or heat welding fastening technique, including, but not limited to: polyolefin in general, as well as, specifically polyethylene, polypropylene, and polybutylene; polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), acrylo-nitrile butadiene styrene (ABS). This film can be produced by known film making processes, such as extrusion, blown tubing, and spun-bonding.
Accordingly, the invention addresses and overcomes the problems posed by the prior art. The invention provides an effectiv
Clarke Paul W. W.
Scruby Timothy M.
Carone Michael J.
Nguyen Son T.
Parker Sheldon H.
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