You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to provisional application Ser. No. 60/943,668, filed on Jun. 13, 2007. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to systems and methods for restoring material to a land area that has been eroded away. 
     2. Description of Related Art 
     The present inventor has previously disclosed methods for restoring topsoil that has been eroded away, and also for dredging ditches in an environmentally friendly and cost-effective manner. Methods for dredging waterways are disclosed, inter alia, in U.S. Pat. Nos. 3,971,148; 4,240,243; 4,434,943; 4,517,754; 4,521,305; 4,575,960; 4,628,623; 4,759,664; 4,896,445; 5,167,469; and 5,211,511, which are incorporated by reference hereinto. These methods utilize a high-pressure nozzle to spray a thin layer of slurry material over a large area. 
     In the &#39;148 patent, a dredge cutter head is described that is self-cleaning; in the &#39;243 patent, satellite harvesters are used to harvest underwater aquatic growth; in the &#39;943 patent, a pump intake cutter head is disclosed for pumping an aquatic growth slurry from a waterway or body of water; in the &#39;754 and &#39;960 patents, a cutterhead attachment for a dredge is described; in the &#39;305 patent, a rotating self-cleaning screen is provided; in the &#39;623 patent is described a turbidity control system for a dredge cutterhead; in the &#39;664 patent, the slurry is formed of a solid material and water at a first location and pumped to a remote location for increasing the elevation of an area at the remote location; in the &#39;445 patent, a waterway is dredged, and the dredged material is used to form a slurry that is then distributed over the adjoining area in a layer sufficiently thin to avoid negative impact on the environment; in the &#39;469 and &#39;511 patents, a slurry distribution system is disclosed. 
     Natural habitat disappearance is a persistent problem, and can be caused by a variety of damaging factors, including, but not limited to, human-caused factors and natural occurrences. Until now, topsoil restoration from ditches has been an expensive and labor-intensive process. 
     Therefore, it would be desirable to provide an apparatus and method for restoring land areas, for controlling elevation, and for improving the efficiency of an excavation process. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is directed to the rehabilitation of land areas that have been subject to erosion, for example. 
     In one embodiment is provided a method for rehabilitating an area of land. The method comprises the step of using an excavating machine to extract dirt or other sedimented material desired to be dispersed over the land area from another area, such as a ditch. The extracted dirt is mixed with water to form a slurry. The slurry is pumped to a high-pressure spray nozzle, and is then sprayed over the land area desired to be rehabilitated. 
     A system of the present invention in one aspect is for rehabilitating an area of land. The system comprises an excavating machine movable to an area such as a ditch. The ditch could have water therein or be dry. An extractor, which can be adapted to add water if the ditch is dry, is affixed to the excavator and is configured to remove material from the ditch and create a slurry therefrom. A hose is in fluid contact with the extractor at a first end and a spray nozzle at a second, opposed end. 
     A pump is provided for pumping the slurry from the extractor into the hose. Also provided is a conveyance tube that leads from the seed container to an aperture in the hose. Means are also provided for directing the spray of slurry over the desired land area desired to be rehabilitated. 
     The present invention provides considerable savings in cost and time to rehabilitate a land area. 
     The features that characterize the invention, both as to organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description used in conjunction with the accompanying drawing. It is to be expressly understood that the drawing is for the purpose of illustration and description and is not intended as a definition of the limits of the invention. These and other objects attained, and advantages offered, by the present invention will become more fully apparent as the description that now follows is read in conjunction with the accompanying drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       THE FIGURE is a schematic diagram of a system for distributing a topsoil slurry over an area to be rehabilitated. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A description of the preferred embodiments of the present invention will now be presented with reference to THE FIGURE. 
     A system  10  ( FIG. 1 ) of the present invention, believed at the time of filing to represent a preferred embodiment, in one aspect is for rehabilitating a land area  11 . The system  10  comprises an excavating machine  12  movable to an area such as a ditch  15 . 
     The ditch  15  could have water therein or be dry. An exemplary excavator  12  known in the art can be used. 
     An extractor  13 , which can be adapted to add water if the ditch  15  is dry, is affixed to the excavator  12  and is configured to remove material from the ditch  15  and create a slurry therefrom. The extractor  13  can comprise, for example, an auger, although this is not intended as a limitation, and may comprise an exemplary extractor  13  such as known in the art. Preferably the extractor  13  comprises a suction extractor, which permits the excavation of very soft and slurried materials without bucket spillage, and with minimum turbidity created in the ditch  15 , which is an improvement over the use of mechanical excavation or mechanical leveling heavy equipment for elevation control. 
     A hose  14  is in fluid contact with the extractor  13  at a first end  20  and a spray nozzle  17  at a second, opposed end  18 . An excavator pump  19  is provided for pumping the slurry from the extractor  13  into the hose  14 . Means are also provided for directing the spray  22  of slurry over the desired land area  11  desired to be rehabilitated, which can include in some instances a booster pump  23  in fluid communication with the slurry between the excavator pump  19  and the spray  22 . The booster pump  23 , if needed, increases the distance of throw of the slurried material by increasing the expulsion pressure. The nozzle  17  can comprise, if desired, a hydraulic directional controlled nozzle for placement control having a safety pressure relief. If desired, a diffuser probe  24  can be inserted into the spray  22 , such as that taught in the current inventor&#39;s co-pending application Ser. No. 61/047,195. Such an element  24  can serve to widen the placement area and reduce the impact of the water column on the spray site  11  by softening and modifying the placement water column into a mist. The spray  22  can be used to deposit a thin layer  26 , for example, or can be used to build up an area to control elevation, wherein the deposited slurry  25  has a greater elevation than the original land area  11 . 
     Means are also provided for directing the spray  22  of slurry over the desired area  11  remote from the ditch  15 . Such a directing means may comprise, for example, “jet spray” nozzle  17  devices such as are disclosed in the previously cited &#39;664 or &#39;445 patents, although these are not intended as limitations. The ability to direct the spray  22  remotely from the ditch  15  can serve to eliminate flow-back into the ditch  15  and minimize re-erosion. The slurry spray  22  can contain additives if desired, such as taught in the current inventor&#39;s co-pending patent application Ser. No. 11/221,378, such as, but not intended to be limited to, seeds or soil amendments. 
     Since the nozzle  17  and hose  14  are movable, the second site  11  can be selected from one or both sides of the ditch  15  without having to move the apparatus  10 . Ditches  15  of a wide range of widths and depths can be excavated, including the very small types of ditch common in agricultural settings or drainage ditches, without changing equipment or experiencing re-flotation difficulties. Excavation can be carried out while moving continuously if desired, avoiding obstacles, thereby increasing production, permitting tight turns, all without stopping, with the apparatus  10  moving under its own power. A plurality of separated excavation sites  15  can be dredged, all without the need for replacement flotation, and carried out with one operator if desired and without the need for auxiliary equipment. The entire apparatus  10  can be unloaded from a trailer, moved to the ditch site  15 , operated, and reloaded onto the trailer by one operator. In some cases it may even be possible to drive the apparatus  10  directly to the site  15 . 
     The material can be distributed remotely from the ditch  15  by, for example, 150-300 feet, and the excavator  12  can be in substantially continuous motion, both features that are not found in the art at present. The present apparatus  10  has been found to have a multiplicity of benefits, among which are a reduction of sedimentation downstream at dams, loss of topsoil into bodies of water such as oceans, reduction of the need for fertilizers, maintenance of irrigation channels, restoration of waterways after a flood, reduction of aerobic bacteria in the sediment, which improves the marine environment, increasing agricultural production through improved drainage control at sites previously recognized as presenting difficulty owing to their small size, and improved topsoil availability. 
     In the foregoing description, certain terms have been used for brevity, clarity, and understanding, but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such words are used for description purposes herein and are intended to be broadly construed. Moreover, the embodiments of the apparatus illustrated and described herein are by way of example, and the scope of the invention is not limited to the exact details of construction. 
     Having now described the invention, the construction, the operation and use of preferred embodiments thereof, and the advantageous new and useful results obtained thereby, the new and useful constructions, and reasonable mechanical equivalents thereof obvious to those skilled in the art, are set forth in the appended claims.

Summary:
A method for rehabilitating a land area comprises the step of using an excavating machine to extract dirt desired to be dispersed over the land area from another area, such as a ditch. The extracted dirt is mixed with water to form a slurry. The slurry is pumped to a high-pressure spray nozzle, and is then sprayed in a thin layer over the land area desired to be rehabilitated. The slurry can also be pumped to the land area at a controllable depth to achieve a desired land profile thereat.