Abstract:
The present invention provides a system for applying a chemical, such as an herbicide, to a surface. A chemical reservoir stores a quantity of the chemical for dispensation to the surface. A flow control unit in fluid communication with the chemical reservoir has a conduit in which the chemical flows. The flow control unit is adjustable to control the rate of chemical flow in the conduit. At least one wiper assembly is in fluid communication with the flow control unit. The wiper assembly includes at least one wick sheet which receives and absorbs the chemical received from the flow control unit and applies the chemical to the surface via a wiping action.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 09/760,982, filed Jan. 16, 2001 U.S. Pat. No. 6,434,880B1. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention relates to an apparatus for the application of chemicals to vegetation, and in particular, to a direct-contact apparatus for the application of herbicide to undesired vegetation without disturbing desired vegetation. 
     BACKGROUND OF THE INVENTION 
     Efficient methods of weed control are essential in order to maximize crop yield using modem agricultural techniques. Weeds are most easily eliminated through the effective use and application of chemical herbicides. Costly herbicides must be applied efficiently. So-called “selective” herbicides contain chemical agents formulated for use with specific types of vegetation. In contrast, non-selective herbicides contain an active chemical agent which kills all vegetation with which it comes into contact. Such non-selective herbicides are therefore less expensive to produce than selective herbicides, and may effectively kill all forms of undesirable weeds. However, in applying non-selective herbicides, care must be taken to apply the chemicals in a manner that targets weeds alone, and not valuable crops. 
     A common method for applying herbicides is direct spraying. Spraying of herbicides suffers from the disadvantages of requiring relatively heavy and expensive equipment. Also, non-selective herbicides can not be applied using this technique because both crops and weeds would be affected. Even when selective herbicides are used, spraying still significantly wastes the herbicide as it is applied on both the crops and the weeds. Thus, efficient use of non-selective herbicides requires a system that minimizes waste and provides for a uniform, controlled application. 
     A relatively new method of weed control that is particularly suited for this purpose is a direct contact application technique, using a so-called “wick applicator”. Wick applicators are an example of direct contact applicators which directly apply the herbicide to weeds by rubbing an absorbent wick-like structure saturated with herbicide onto the weeds. Wick applicators are advantageous to use since comparatively new “systemic” herbicides, as opposed to traditional conventional herbicides which burn vegetation, may be used with such applicators. After contact, a systemic herbicide is absorbed by the vegetation and permeates the root systems to kill weeds without affecting the soil. 
     Mechanisms which employ wick applicators mounted to farming vehicles that traverse crops and apply herbicides through a wiping action are known. Due to the variety of crops, a wick applicator&#39;s particular structure is dictated by the size, layout, and density of the weeds relative to the crops. Since many weeds tend to initially outgrow crops in the early stages of growth, several direct contact applicators have been developed to take advantage of this differential in plant height. For example, devices in which a wiper bar is mounted to a hydraulic positioning assembly adjusted to conform to the nominal height of weeds while remaining above the crops growing below are known. However, crops which outgrow the nominal height of the weeds are subject to destruction by the applicator mechanism coming into physical contact therewith. This technique is also inherently inefficient in that it targets weeds relatively late in their growth cycle, in which the weeds have already diverted a significant amount of soil nutrients from the crops. 
     Also, in applying herbicide in a wiping action, the amount of herbicide applied is a function of the time in which the herbicide-saturated wick is in contact with weeds as the apparatus traverses the field. To increase this contact time, devices which take advantage of vertical wick positioning have been proposed. These devices provide structures in which the angular orientation of the wick with respect to the direction of travel of the tractor allows for greater contact time. However, these devices suffer from the disadvantage of using rope-shaped wicks with a low relatively low contact surface area and thus a low contact time. 
     Another shortcoming of the known structures is that they fail to work when applied to crops with furrows, or spaces between rows of plants. To effectively target weeds in furrows before they have appreciably grown, direct contact applicators must conform to the particular shape of the furrows. Known devices use a deformably rigid wick applicator of annular shape with a relatively low contact surface area. This arrangement is disadvantageous because the applicator must be manually deformed to conform to the particular shape of different furrows. The manual deformation requirement results in a relatively low contact time with the weeds, the failure to contact and apply chemicals to the weeds and undesired contact with seeded areas and wanted vegetation. 
     Thus, it is desirable to have an apparatus for applying chemicals to vegetation, in particular non-selective herbicidal chemicals, which is suitable for use in furrows having varying cross-section, and which has sufficient flexibility so as to closely conform to the contours of the furrows. It is further desirable to provide a large applicator contact surface area to apply the chemical to the weeds. And it is further desirable to provide an injection system to uniformly distribute chemical in a controlled and efficient manner from a supply source onto the applicator surface. 
     SUMMARY OF THE INVENTION 
     The present invention advantageously provides a system for applying a chemical, such as an herbicide, to a surface. For example, the system provided by the present invention makes the application of a non-selective herbicide to undesired vegetation growing in a furrow efficient, cost effective and convenient. 
     One aspect of the present invention provides a chemical applicator apparatus for applying a chemical from a chemical supply source to a surface, in which an intake manifold has at least one fluid receiving opening and at least one fluid distribution opening. Each fluid receiving opening receives a chemical flow from the chemical supply source and each fluid distribution opening distributes the received chemical flow. At least one planar interface element is in fluid communication with a respective fluid distribution opening. Each planar element receives the chemical flow from the fluid distribution opening. At least one wick sheet is coupled to and is in fluid communication with the at least one planar interface element. Each wick sheet absorbs the chemical flow from the at least one planar interface element and applies the chemical flow to a surface in contact with the wick sheet. 
     As another aspect, the present invention provides a system for applying a chemical to a surface, in which a chemical reservoir storing a quantity of chemical for dispensation to the surface is provided. A flow control unit is in fluid communication with the chemical reservoir, and includes a conduit in which the chemical flows from the chemical reservoir through to at least one wiper assembly. The flow control unit is adjustable to control the rate of chemical flow in the conduit. Each wiper assembly is in fluid communication with the flow control unit. At least one wick sheet is coupled to the wiper assembly. Each wick sheet absorbingly receives the chemical from the flow control unit and wipingly applies the chemical to the surface. 
     As yet another aspect, the present invention provides a chemical applicator apparatus for applying a chemical from a chemical supply source to a surface. The applicator comprises a frame, at least one wick assembly coupling member, and a plurality of wick assemblies. Each wick assembly coupling member has a first end portion adjustably coupled to the frame, and a second end portion opposite the first end portion. Each wick assembly is individually coupled to the second end portion of the wick assembly coupling member. The plurality of wick assemblies are in fluid communication with the chemical supply source, each wick assembly wipingly applying the chemical to the surface. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
     FIG. 1 is a schematic of the an herbicide applicator system; 
     FIG. 2 is a perspective view of an herbicide applicator mechanism of the present invention mounted to a farming vehicle illustrating a manner in which the herbicide is applied to a field of furrowed crops; 
     FIG. 3 is a diagram of an herbicide source and flow control system for use with the applicator device of the present invention; 
     FIG. 4 is a rear view of the wiper assembly illustrating the herbicide intake manifold attached thereto with dispensing tubes distributing herbicide to the wiper assembly; 
     FIG. 5 is a side view of the wiper assembly of FIG. 3; 
     FIG. 6 is a plan view of an herbicide intake manifold on the wiper assembly; 
     FIG. 7 is a perspective view of the top of an herbicide injection interface; 
     FIG. 8 is a perspective view of the bottom of the herbicide injection interface; 
     FIG. 9 is a cross-sectional view of the wiper assembly taken from section  9 — 9  in FIG. 4; 
     FIG. 10 is a cross-sectional view of the wiper assembly taken from section  10 — 10  in FIG. 9; 
     FIG. 11 is a rear view of the wiper assembly showing the planar arrangement of the array of wick sheets; 
     FIG. 12 is a cross-sectional view of the wiper assembly taken from section  12 — 12  in FIG. 4; and 
     FIG. 13 is a perspective view of an alternate arrangement of the wiper assembly. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As used herein, the term “herbicide” refers to a chemical formulated to kill vegetation for agricultural applications. The herbicide is preferably in liquid form under standard temperature and pressure conditions, or a liquid solution or liquid suspension of solid herbicide. It is also understood that the present invention is not relegated to use solely with herbicides. It is contemplated that any form of chemical agent, such as a pesticide or fertilizer may be used, as long as the chemical agent is dispensable in liquid form. 
     Referring now to the drawings, in which like reference designators refer to like elements, there is shown in FIG. 1 a schematic diagram of an herbicide applicator system constructed in accordance with the principles of the present invention, and designated generally as  5 . Herbicide applicator system  5  preferably includes: (i) a vehicle  10 , (ii) an herbicide reservoir  15 , (iii) a flow control apparatus  20 , and (iv) one or more wiper assemblies  25 . The herbicide reservoir  15  serves as the herbicide container. The flow control apparatus  20  meters and controls the flow of the herbicide from the herbicide reservoir  15  to the wiper assemblies  25 . Wiper assemblies  25  apply the herbicide to the vegetation to be destroyed. 
     As illustrated in FIG. 2, in a preferred embodiment, the wiper assembly  25  is mounted to the vehicle  10 , along with a herbicide reservoir  15 , and a flow control apparatus  20 , and moved across a field of crops laid out in a commonly used configuration of crop rows  30  with furrows  35 , or spaces, between the crop rows  30 . One or more wiper assemblies  25  are preferably fixed to the vehicle  10  by an elongated member, referred to more generally as a tool bar  40 . 
     Although any number of wiper assemblies  25  may be mounted to the tool bar  40 , the preferred embodiment shows a pair of wiper assemblies  25  fixed to the opposite ends of the tool bar  40  at a width such that the bottom portions of the wiper assemblies  25  fit into, travel within, and adapt to the contours of the furrows  35 . 
     A schematic diagram of the flow control apparatus  20  is shown in FIG. 3, illustrating the manner in which herbicide is supplied to each of the wiper assemblies  25 . The herbicide flows from the reservoir  15  through conduits  45 , thereafter through a cut-off valve  50 , and thereafter into piping  55 . The piping  55  includes a tee  57  coupled to a discharge valve  60 . The herbicide exits the piping  55  and flows through a filter  65 . The filter  65  is adapted to remove undesired impurities and particulate matter from the herbicide. After filtration, the herbicide flows through a conduit  67  into a pump  70 , thereafter through conduit  72  and into piping  73 . The piping  73  includes a tee  74 . Upon exiting the piping  73 , the herbicide flows through another cut-off valve  75  and continues flowing through one or more conduits  80  and tees  85  such that a single source conduit  90  is in fluid communication with each of the wiper assemblies  25  attached to the tool bar  40 . 
     A pressure gauge  95  is preferably coupled to piping  73 , and is employed to monitor the positive gauge pressure of the herbicide flowing downstream of the pump  70 . A return conduit  100  can also be connected to the tee  74 , thereby providing an operator with a way to re-fill the reservoir  15  when emptied. 
     The above-described conduits and pipes can be manufactured from any material suitable for transporting liquid chemicals such as herbicides, including but not limited to: flexible polymer or rubber tubing, rigid or semi-rigid pipes made of metals, polyvinylchloride and the like. 
     The pump  70  may be used to either draw herbicide from the reservoir and thereby pump it at positive gauge pressure into the wiper assemblies  25 , or may be used to fill the reservoir, when cut-off valves  50  and  75  are closed and discharge valve  60  is open, with a supply of liquid herbicide connected to the discharge fitting  105 . 
     Although the preferred embodiment of the flow control apparatus  20  includes a pump  70  to move the herbicide from the source reservoir  15  to the wiper assemblies  25 , an alternative arrangement for moving the herbicide, such as a gravity feed, may be used. 
     FIG. 4 shows a rear view of a wiper assembly  25  constructed in accordance with the principles of the present invention. The wiper assembly  25  preferably includes a mounting bar  110 , a mounting L-beam  111 , a wick coupling member  112 , an intake manifold  113 , one or more herbicide injection interface elements  114 , one or more wick-sheets  115 , one or more conduits  120 , a tee linkage  125 , a flat mounting beam  130 , a stabilizing rod  135 , one or more block weights  140 , and an intake fitting  141 . 
     Referring to FIG. 4, herbicide is preferably pumped at positive gauge pressure through a conduit  90  connected to a wiper assembly  25 . The wiper assembly  25  is mounted to the tool bar  40  preferably by the mounting bar  110 . The mounting bar  110  can be manufactured from a variety of materials, either being somewhat flexible, such as graphite or carbon composite, or substantially rigid, such as metal or polyvinylchloride. The mounting bar  110  is fixed at its upper end to the tool bar  40  by a rotatable tee linkage  125 , such that the mounting bar  110  rests at a vertical position, substantially perpendicular to the ground. As herbicide is applied to the ground through a wiping action, the wiper assemblies  25  are free to rotate about the tee linkage  125  axis of rotation and thus deflect with respect to the vertical rest position of the mounting bar  110 . 
     The herbicide enters the wiper assembly  25  through an intake manifold  113  incorporated therein. The intake manifold  113  includes an intake fitting  141  coupled to the conduit  90 , which supplies liquid herbicide to the intake manifold  113  from the flow control apparatus  20 . Herbicide then flows from the intake manifold  113  through one or more conduits  120 . The end of each conduit  120  is coupled to an herbicide injection interface element  114 . Each injection interface element  114  is disposed adjacent to the surface of a wick-sheet  115 , whereby herbicide flows therethrough to saturate and occupy the liquid-absorbing wick-sheet  115 . The herbicide injection interface element  114  acts as a distributor member for the dispersal and application of herbicide into the wick-sheet  115 . 
     The wick sheets  115  are mounted to the lower edge of wick coupling member  112 . Wick coupling member  112  is clamped in place between a first mounting L-beam  111 , and a second flat beam  130 . Wick coupling member  112  serves as an intermediate, stabilizing base element to keep the wick sheets  115  disposed in substantially one plane. The wick sheets  115  are further preferably arranged in a planar array of one or more layers, as more fully described herein below. The stabilizing rod  135  is mounted to one or more of the wick sheets with block weights  140  fixably attached to the ends of the wick sheets  115 , preferably at substantially the lower end of the wick sheets  115 . By mounting the stablizing rod  135  across the array of wick-sheets  115  as shown in FIG. 4, the orientation of the stablizing rod  135  being transverse to the direction of travel of the wiper assembly  25  as herbicide is applied, the wick sheets  115  may be kept substantially in one planar space, without deforming or curling, so as to allow for efficient application of herbicide. 
     FIG. 5 shows a side view of the wiper assembly  25  displayed in FIG.  4 . Referring now to FIG. 5, the mounting bar  110  is fixed at its lower end to a rigid L-beam  111  perpendicular thereto. The mounting bar  110  and the rigid L-beam  111  form a frame which provides support for many other elements of the wiper assembly  25 . The mounting bar  110  is in a horizontal position parallel to the ground and transverse to the direction of motion of the vehicle  10 . As illustrated in FIG. 5, the entire wiper assembly  25  is substantially arranged within the plane subtended in space by the mounting bar  110  and rigid L-beam  111 . One or more fastener rings  142  may be used, surrounding the conduits  120  and fixed to the wick coupling member  112 , to prevent the potential entanglement of conduits  120  with outside objects. 
     FIG. 6 is a diagram showing a plan view of an intake manifold  113  mounted to the rigid L-beam  111 . Referring now to FIGS. 5 and 6, a wick coupling member  112  of flexible yet substantially rigid material, such as heavy-gauge rubber or fiber-mesh, is placed at its upper end between the rigid L-beam  111  and a second flat rigid beam  130  parallel thereto. Wick coupling member  112  is preferably trapezoidal in shape, wherein the lower edge is wider than the upper edge coupled between the rigid L-beam  111  and the flat rigid beam  130 . The rigid L-beam  111  and flat rigid beam  130  are clamped at their respective distal ends by fasteners, such as a nut  143  and bolt  144 , so that the wick coupling member  112  is tightly sandwiched therebetween. One or more clamps  145  are fixed to one face of the flat rigid beam  130  to couple an herbicide intake manifold  113  to rigid beam  130 . 
     The intake manifold  113  is preferably comprised of a hollow element  150  fitted with caps  154  at each end. The hollow element  150  is preferably tubular in shape and is fixed in place by clamps  145 , and oriented in a substantially horizontal position parallel to the flat rigid beam  130 . The intake manifold  113  is further comprised of at least one inlet opening  155  in the tubular element  150 , allowing for the flow of herbicide into the intake manifold  113 . As shown in FIG. 5, the intake manifold  113  is coupled to an inlet fitting  141 , which is thereby coupled to the downstream end of the conduit  90  supplying herbicide from the flow control apparatus  20 . 
     Referring to the intake manifold  113  shown in FIG. 6, herbicide at positive gauge pressure flows into the intake manifold  113  whereby the herbicide is distributed and exits through one or more exit openings  165  provided at the lower surface of intake manifold  113 . The exit openings  165  are preferably provided such that the opening diameter in combination with the positive gauge pressure of herbicide flowing therethrough substantially evenly distributes the herbicide among exit openings  165 . Each of the exit openings  165  is fitted with a corresponding coupling  170 , which is thereby coupled to a conduit  120 . The lower end of each of the flexible conduits  120  is coupled to an herbicide injection interface element  114  and affixed thereto preferably using tensile traction between the interface element  114  and flexible conduit  120 . 
     FIGS. 7 and 8 illustrate a top perspective and bottom perspective, respectively, of the herbicide injection interface element  114 . The herbicide injection interface element  114  includes a conduit member  185 , and a planar member  190 . The conduit member  185  includes an inlet opening  191  to allow for the inflow of herbicide. The planar member  190  has an opening  192  therein, the opening  192  having a central axis  193 , and an inlet side surface  194  and an exit side surface  198 . The planar member  190  is preferably made of a substantially rigid material, such as plastic, and preferably has a circular or polygonal shape and a large surface area to volume ratio, like that of a credit card. The opening  192  is preferably placed approximately at the center of the planar member  190 . The substantially rigid conduit member  185  passes through the opening  192 . One end of the conduit member  185  is positioned through the interior of the opening  192 . The exterior surface of the conduit member  185  is secured to the contact surface of the opening  192  using a suitable adhesive, or by means of compressive traction at the contact surfaces of the conduit member  185  and planar member  190 . In the alternative, conduit member  185  can be molded as an integral part with planar member  190 . 
     The conduit member  185  is preferably oriented substantially perpendicular to the planar member  190 , or in such an orientation that allows for the conduit member  185  to be fixed to the planar member  190  whereby there preferably exists a distance between the inlet end  191  of the conduit member  185  and the inlet side surface  194  of the planar member  190  sufficient to allow for the herbicide injection interface element  114  to be arranged in the wiper assembly  25  as described below. Alternatively, it is understood that the injection interface element  114  may be designed in numerous ways, with or without an element such as conduit member  185 , such that herbicide is supplied from a source conduit to the planar member  190 , and that the embodiment disclosed herein is but only one preferred arrangement of the device. 
     As shown on FIG. 8, the exit side surface of the flat planar member  190  is preferably covered with a matrix of fluid-permeable hook and fastener material  210 , such as Velcro, placed thereupon so as to enable the herbicide injection interface element  114  to be securely affixed to the planar array of overlapping wick sheets  115 , as more specifically illustrated in FIGS. 9 and 10. Alternatively, planar member  190  may be manufactured to integrally include the matrix of fluid-permeable hooks and ridges by molding the exit side surface  198  of planar member  190  to comprise a layer of such fluid-permeable hooks and ridges, such that the features of planar member  190  and the matrix of fluid-permeable hook and fastener material  210  are combined into a single unitary element. The exterior surface of the distal edge portion of conduit member  185  protruding through opening  192  is circumscribed by a planar lip element  199  attached to the conduit member  185 . Planar lip element  199  has a flattened toroidal washer-like shape. Planar lip element  199  is positioned to spatially affix the orientation of conduit member  185  to planar member  190  such that the end of conduit member  185  (excluding the portion circumscribed by planar lip element  199 ) is substantially flush with exit side surface  198 . Planar lip  199  includes an outer surface  205  shown in FIGS. 7 and 8. 
     FIGS. 9 and 10 show a herbicide injection interface element  114  positioned within wick sheets  115 . The conduit member  185  of the herbicide injection interface element  114  is coupled to a flexible conduit  120  to facilitate the flow of herbicide into the wick sheets  115 . FIG. 10 illustrates the herbicide  200  flowing into the conduit member  185 . As shown in FIG. 10, the liquid herbicide  200  flows out from the rigid tubular conduit member  185  and is distributed at the exit side surface  198  of the planar member  190  through the contact plane formed between the hook and fastener material  210  and the wick sheet  115 . Though the combined forces of gravity, hydraulic pressure, and capillary action, the liquid herbicide  200  flows throughout the planar array of wick sheets  115  such that the wick sheets  115  are substantially saturated. The wick sheets  115  are sufficiently saturated when herbicide permeates the wick sheet  115  and is exposed on the exterior surfaces of the wick sheet  115 . At this sufficient saturation level, herbicide may be applied using a wiping action to any surface with which the wick sheet  115  comes into contact. Of course any other arrangement for affixing the injection interface element  114  to wick sheets  115  can be used as long as a fluid path for the herbicide is provided as described below. 
     FIG. 11 shows a preferred arrangement of wick sheets  115  attached to the wick coupling member  112  so as to allow for the application of herbicide to the desired surface. Referring now to FIG. 11, an array of planar overlapping wick sheets  115  are attached at their upper end by fasteners  220  to the lower end of the wick coupling member  112 . The wick sheets  115  are overlaid to form parallel planar layers placed adjacent to one another. Two parallel planar layers are shown in FIG.  11 . Each of the individual strips of wick sheets  115  are positioned side by side, such that the boundary  217  between one pair of wick sheets  115  oriented on a first layer is overlaid at approximately the midpoint of another wick sheet  115  in a second adjacent layer. 
     The wick sheets  115  are preferably made of a suitable substantially flexible, liquid-absorbing material, such as a dense woven fabric or synthetic polymer mesh, so as to absorb a substantial amount of herbicide flowing from the plurality of injection interface elements  114  embedded between the parallel planar array of wick sheets  115 . 
     It is emphasized that the foregoing spatial arrangement of the wick sheets  115  is only one example of a preferred embodiment of the present invention. Any number of alternative arrangements may be used so as to provide for the application of herbicide using herbicide-saturated wicks applied to a desired contact surface using a wiping action. For example, although FIG. 11 shows an array of parallel planar wick sheets  115  of substantially equal length, the arrangement of wick sheets  115  can also incorporate individual wick sheets  115  of varying length. 
     FIG. 12 is cross-sectional view of the wick sheets  115 , illustrating the capability of the wick sheets  115  to deform and thereby conform to the desired application surface. Due to the flexibility of the parallel planar array of wick sheets  115 , as illustrated by the hash-lines in FIG. 12, the liquid herbicide is applied in such a manner as to allow the wiper assembly  25  to substantially deform and conform to the contours of the ground in the furrows  35 . This enables the herbicide to efficiently cover the targeted surfaces and be applied with a minimum of waste, because the wick sheets  115  are saturated only to the point of allowing the herbicide to adhere to an exterior surface through contact and not through excess dripping. Of course, this result is contingent on the user effectively metering the overall flow of herbicide through the apparatus so that the wick sheets  115  are not excessively saturated. It is understood that the particular level of wick sheet  115  saturation required for the efficient operation of the device can be ascertained by the user through (i) repeated iterative operation of the device, or (ii) by observing the flow of herbicide as it is applied, and accordingly making subsequent adjustments to the flow control apparatus  20  and subsequent corresponding herbicide flow rate through the apparatus. 
     As shown in FIGS. 4 and 12, a rigid stabilizing rod  135  is optionally placed horizontally at the lower end of the planar array of wick sheets, being parallel thereto and secured at either end thereof by a solid block weight  140 . The rigid stabilizing rod  135  serves to prevent the highly flexible array of wick sheets  115  from becoming entangled. This allows the array of wick sheets  115  to substantially remain in a single plane so as to enable uniform application of herbicide onto the ground. 
     In operation, as illustrated in FIGS. 2 and 4, the parallel planar array of wick sheets  115  of the wiper assembly  25  is dragged behind the vehicle  10  through a furrow  35  in a field so as to apply liquid herbicide onto any vegetation growing therein. The weeds and other undesired vegetation in the furrows  35  come into contact with the herbicide, and the desired response, such as killing the weeds, is facilitated. 
     FIG. 13 shows another aspect of the invention, in which the parallel planar array of wick sheets has preferably been replaced by a plurality of individual co-planar wick assemblies  230 . The wick assemblies  230  include a planar wick sheet  235  coupled to at least one injection interface element  114 , and are fixably attached to a tool bar  240 , by one or more elongated members  245 , preferably made of an elastically deformable solid material, such as a graphite, fiberglass, or polymer rod. The herbicide is again supplied via an inlet tube  250  to a manifold  255 , and thereby distributed to the individual co-planar wick sheets  235  by flexible conduits  260 . At the end of each flexible conduit, an injection interface element  114  is provided and used in a manner similar to that of the previously discussed embodiment. Each individual planar wick sheet  235  is further spread out to retain a substantially planar shape by a reinforcement sheet  265 . Reinforcement sheet  265  is preferably made of a substantially rigid material, such as plastic or wire-mesh. 
     The present invention therefore advantageously provides a system which allows a chemical such as a non-selective herbicide to be safely applied to undesired vegetation, such as weeds growing in a furrow, in a manner which does not waste chemical product, and applies the chemical to the undesired vegetation without disturbing the desired vegetation. By applying the chemical to the surface via a wiping action, the present invention is useful for direct surface contact with undesired vegetation growth as well as contact with a surface which may have undesired seedlings or ungerminated undesired seeds. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings without departing from the scope and spirit of the invention, which is limited only by the following claims.