The present invention is directed to a sprayable hydromulch which is effective in reclaiming land, and which is particularly useful in planting seed to establish ground cover on reclaimed strip mining areas.

BACKGROUND OF THE INVENTION 
Soil erosion is a phenomenon which occurs in a wide variety of situations. 
Erosion is accelerated by the action of wind and rain and is particularly 
troublesome in conditions of poor soil coherence. Land which has no ground 
cover, and particularly sloped land, will not retain the seeds of plants 
that might germinate to provide a root system to hold the soil in place. 
In such situations, rain storms fashion streams of water which carry away 
the seeds as well as the surface soil. 
In the reclaiming of land from strip mine areas, inevitably large areas of 
soil entirely devoid of ground cover are created. In order to make such 
land attractive, it is frequently sloped, which aggravates the erosion 
problem. Further, the formation of highways and roads requires the making 
of cuts, embankments, culverts and the like which involve steeply sloped 
bare soil which is exposed to weather and prone to erosion if not stopped. 
In order to apply seed and fertilizer rapidly, it is customary to spray 
aqueous slurries of seed, fertilizer and other nutrients on soil to be 
reclaimed. It is also common to distribute a layer of straw, by hand, over 
the surfaces of soil which have been thus planted. However, straw is 
susceptible to loss by wind and rain, and has proven to be ineffective on 
sloped surfaces. The prior art has proposed the use of a wide variety of 
materials to hold the straw in place, such as asphalt emulsions and the 
like. Various binding systems are proposed in the prior art, including 
U.S. Pat. No. 3,292,307, U.S. Pat. No. 3,482,353, U.S. Pat. No. 3,696,559, 
and Re. Pat. No. 28,950. 
Further, the prior art has described mulch systems produced from cellulosic 
fibers, such as U.S. Pat. Nos. 3,017,720 and 3,165,862. These patents 
describe a mulch which comprises straw or other similar material which is 
adhered together using asphalt as an adhesive. While many of the 
compositions described in the prior art have been successful in producing 
mulch compositions satisfactory to accomplish a re-seeding of soil, such 
compositions, as a practical matter, have not been adapted to spraying. 
Portable equipment which is adapted to spray aqueous slurries of seed and 
fertilizer and methods of spraying are described in the prior art, 
including U.S. Pat. Nos. 2,789,399, 2,842,897, 2,878,617, 3,091,436, and 
3,292,307. The equipment described by the prior art is adapted to spray 
aqueous suspensions of finely divided cellulostic matter, chiefly chopped 
or cut-up cardboard and paper stock mixed with seeds and fertilizer to 
produce a mulch. The advantage of such equipment is its ability to spray 
the mulch on relatively inaccessable places which are not adapted to hand 
placement of the mulch. 
The prior art, however, has failed to provide a hydromulch wherein the 
mulch, the seed, fertilizer, and lime necessary to support the growth of 
vegetation can be applied in a single operation. The prior art has relied, 
in general, on the hand application of hay or straw to provide the 
necessary mulch. 
SUMMARY OF THE PRESENT INVENTION 
The present invention provides a sprayable mulch, the principal component 
of which is hay which is cut or milled to give a mixture of fibers of 
diverse sizes, and preferably fibers having a distribution of various 
sizes between about 1/4 inch to 6 inches in length, with an average 
between 21/2 and 4 inches in length. 
The mulch of the present invention has as its principal component cut and 
cured hay which is preferably hammer milled to give a certain average size 
and which must contain a distribution of particle sizes within the broader 
size range. The second required component of the hydromulch composition is 
shredded and/or chopped paper, preferably magazine stock, to provide 
fibers or particles within certain size ranges. Preferably the composition 
also includes a binder agent or adhesive such as a naturally occuring gum 
which assists in holding the mulch composition in place after application. 
It is also preferred to include a coloring agent in the hydromulch. 
In the preferred embodiment, the pumpable hydromulch of the present 
invention comprises, on a dry weight basis, hay 80-80%, paper magazine 
stock 10-17%, binding agent up to 1.5%, coloring agent up to about 1.5%. 
In the preferred embodiment the hay is hammer milled or otherwise cut from 
its original size to give an average fiber length of about 21/2 to 4 
inches, but which includes pieces ranging from 1/2 inch to 6 inches. The 
paper magazine stock is preferably shredded into 1/4 inch strips and then 
chopped into lengths between 1/4 inch and 1 inch. Thus the paper particles 
are generally smaller in size than the hay fibers. 
In a most preferred embodiment, the pumpable mulch comprises, on a dry 
basis, the following approximate formula: 
Hay 85% by weight 
Paper Magazine Stock 12% by weight 
Binding Agent 1.5% by weight 
Coloring Agent 1.5% by weight 
Those skilled in the art will understand that the foregoing percentages are 
approximate and that wide variations may be made therein without loosing 
the advantages of the present invention. 
Although applicant does not wish to be bound by the theory, it is 
postulated that the foregoing composition produces superior results 
because the paper magazine stock cooperates with the hay, when the 
composition of the present invention is used. It can be demonstrated that 
when the mulch of the present invention is applied to the soil, the larger 
particles of hay form a web of fibers suspended above the soil and that 
the fibers are held in the web formation by the binding agents and the 
naturally occurring binders. Because of the diverse particle sizes of the 
materials used in the composition of the present invention, it is 
postulated that upon application of the mulch to the soil, the fine 
particles, i.e., paper stock and some of the smallest hay particles, fall 
to the soil to form a monolithic mat of paper fibers which covers the 
soil. The resulting paper mat exists beneath the fibrous network of the 
hay which is suspended above the ground level because of the fibrous and 
springy nature of the hay fibers. 
During the first rains after the application, further paper particles fall 
or are washed out of the hay to join the paper mat which covers soil 
underneath the web of hay. The paper mat which covers the soil functions 
to secure the seeds against the soil and to hold the moisture in the soil 
until the paper rots 3-5 weeks after application. The seeds generally 
germinate about 4 weeks after application, when the paper rotting process 
takes place. During the first 3-5 weeks after application, the hay serves 
to protect the underlying paper mat from erosion caused by rain, i.e., 
rain drops will hit the hay web first, and thus shatter before dropping 
onto the paper mat below. After the rain drops hit the hay, the shattered 
drops or fine spray fall down onto the paper mat, where the moisture is 
held, thus promoting the germination of the seeds. Thus the web of hay 
prevents disruption of the paper mat and the resulting erosion. 
Moreover, through the first several weeks following the application, the 
web of hay which is positioned above the soil acts as a thermal insulator, 
thus shielding the seeds and the soil on which they are positioned from 
the extreme heat of the day and extreme cold of the night. Thus the hay 
promotes an even temperature and moist conditions in the seeds, which 
encourages a high proportion of germination. 
After several months, the hay which forms the web begins to decompose. By 
this time, the paper web has decomposed and the seeds have germinated. 
Thus, as the hay begins to decompose the nutrients in the hay become 
available to the seedlings. 
In accordance with the present invention, the hay employed may be grass of 
any type which is cut and cured for fodder. It includes grass and grass 
seed of various types and varieties, clover, alfalfa, as well as other 
forage plants, and the like which is cut and dried and chiefly grown for 
the purpose of using the fodder for animals. The hay is the preferred 
fibrous material used in the present invention because it contains a 
substantial quantity of seed, and thus is self-seeding, and includes many 
materials adapted to serve as plant nutrients. It is known that hay has a 
substantial content of nitrogen and growth promoting minerals. 
In accordance with the present invention, the mulch comprises a major 
portion of hay and preferably from 80-90% by weight of hay, because the 
hay provides a sufficient seed and nutrient content. 
A minor amount of paper stock must be included in the mulch composition. In 
the preferred embodiment, shown above, about 12% by weight of the 
composition comprises paper magazine stock. The use of at least 10% by 
weight of magazine stock, chopped or cut to fairly small particle sizes, 
is adequate to form a mat on the soil as explained above. The magazine 
stock is preferred over other forms of paper or cellulose fibers because 
magazine stock is usually clay coated and the clay appears to function as 
a binder or adhesive for the paper mat. Sufficient paper magazine stock 
must be included to form a mat over the soil, but the use of more than 
15-17% does not improve the mat and is not preferred because the excess 
paper provides little if any plant nutrients or other benefits. 
Alternatively, a small amount of newspaper stock or cardboard or other 
cellulose-based fibers may be used in place of the magazine stock, 
provided they are finely chopped, be employed, but it is preferred that at 
least half of the mat forming material be comprised of paper magazine 
stock. 
As is shown in the preferred embodiment above, it is preferred to use about 
1.5% by weight of binding agent. It has been found that Karaya gum 
produces very satisfactory results and it is preferred over all other 
binding agents. Broadly speaking, however, the binding agent may be any of 
the naturally occuring gums, asphalt, and other materials which will tend 
to adhere the fibers of the hay to avoid rain enduced erosion. Those 
skilled in the art will know that wet hay, in of itself, is sticky and, 
when placed on a solid surface will tend to adhere thereto. Thus, it is 
possible to use the composition of the present invention with little or no 
binder if the composition is to be applied to relatively level surfaces. 
However, because in most cases, i.e., strip mine land reclaimation, many 
sloped surfaces are encountered, it is generally preferred to use a 
binder. While it has been found that good results may be obtained using up 
to about 1.5% by weight of a gum-type binder, based on the weight of the 
other dry materials, greater proportions of binder materials may be used, 
but because of economic considerations, more than about 1.5% by weight of 
binder is considered to be economically impractical. 
As is shown in the preferred embodiment above, it is preferred that the 
mulch composition of the present invention include a dye or coloring 
agent, such as Calcozine Green. Such coloring agents may be used at a 
level of about 1.5% by weight based on the overall solids composition. 
While green dye is preferred for aesthetic reasons, other colors may be 
used. The coloring agent is used chiefly for aesthetic purposes, in that 
it serves no mechanical or organic purpose in the composition. The 
coloring material functions to show the operator of the spraying equipment 
what areas have been covered with hydromulch and thereby avoid gaps and 
overlapping in the application of the hydromulch. 
The sprayable hydromulch of the present invention may be applied using 
conventional mulch spraying equipment, such as the equipment manufactured 
by Finn Equipment Company of Cincinnati Ohio. Preferably the Finn 
equipment is used with a modified wear plate, which has a larger orifice 
and a greater taper than the conventional wear plate. Specifically it has 
been found that the 111/2 inch diameter, 11/2 inch thick wear plate which 
has a 77/8 inch opening which tapers down to 33/4 inches provides useful 
results. 
In order to produce the pumpable hydromulch of the present invention, it is 
essential to process all of the components to meet the size criteria, 
which, as a practical matter requires that the mulch be prepared under 
given conditions. It has been found that passing the raw materials from 
the hydromulch through two tandem hammer mill operations will produce a 
mulch having a satisfactory range of particle sizes. More particular, it 
has been found that the hay and the paper magazine stock, in appropriate 
proportions can be mixed together and fed through a hammer mill to produce 
materials on the average of about the 2-6 inch size range. At this point, 
the required amount of Kayara gum is added and the resulting mixture is 
passed through a second hammer mill wherein the size of the fiber is 
reduced to an average of about approximately 21/2 to 4 inches. At this 
point the mulch contains fibers which are as long as 6 inches, and as 
small as 1/4 inch, with the average being about 21/2 to 4 inches. The 
milled mulch may be air transported, i.e., using pneumatic conveyors. 
Pneumatic conveyors are adaptable to spraying the resulting mulch with a 
dye at the level desired. 
The mulch may be packaged in bags for use and shipment. Although plastic 
bags are preferred, the present invention is not limited to any particular 
form or style of shipping container. 
The hydromulch of the present invention is used by placing it in tanks 
which are subsequently filled with water to provide a pumpable suspension. 
Most conventional spraying equipment is provided with a stirring 
capability which is adequate to form a sprayable suspension with the mulch 
of the present invention. Conventional emulsifiers may be added during the 
manufacture of the mulch or when the aqueous suspension is made up, but 
emulsifiers are not considered to be essential. 
The hydromulch may be used with the supplemental seed and fertilizer. 
Preferably, the seed is mixed with the water first, followed by the 
fertilizer and the mulch in either order. Because the hay which is used in 
the hydromulch of the present invention is preferably reduced in size by 
passing the hay through a hammer mill, it is inevitable that some of the 
seed which is naturally found in the hay will be destroyed. In this case 
it may be desirable to add supplemental seed and/or fertilizer to the 
hydromulch. For example, it has been found that approximately 100 pounds 
of seed per acre may be used to supplement the naturally occuring seed in 
the mulch of the present invention. Generally the seed and/or fertilizer 
is added at the time the mulch is mixed with the water in the hydroseeder 
in order to provide the greatest flexibility of seed and fertilizer 
combinations to be used with the mulch. 
While those skilled in the art will be aware that various quantities of 
supplemental seed and supplemental fertilizer may be used with the mulch 
of the present invention, it is generally contemplated that an additional 
100 pounds per acre of seed and about 60 units of nitrogen, 60 units of 
phosphate, and 60 units of potash per acre employed with mulch quantities 
as indicated above, will produce satisfactory results. 
The mulch of the present invention preferably applied to the land to be 
reclaimed on a variable basis depending upon the slope of the land. 
Generally and relatively flat land, from 500 to 600 pounds of mulch per 
acre is desired. Because there is little erosion problem with flat land, 
it has been found that this much mulch provides temperature or thermal 
insulation and moisture control adequate to have adequate germination and 
growth of the seed. Generally it has been found that 100 pounds of mulch 
per acre should be added to each two degrees of slope and up to 1500 or 
1600 pounds of mulch per acre can be used. 
The sprayable hydromulch of the present invention is used by mixing it with 
water to form a suspension. Commercially available hydromulch spraying 
equipment have tanks sufficient in size to hold 2500 gallons of water. In 
operation, the tanks are filled with water and sufficient hydromulch of 
the present invention is added to form a slurry or suspension which may be 
sprayed on the land and soil to be reclaimed. For instance, it has been 
found that good results are obtained with 500 pounds of mulch mixed with 
2500 gallons of water when sprayed per acre of relatively flat land. 
Steeper slopes, require a greater quantity of mulch per acre to avoid 
erosion. It has been found that 1500 pounds of mulch mixed with 2500 
gallons of water per acre provide good reclaimation of sloped land. 
The following examples serve to illustrate the use of the sprayable 
hydromulch compositions within the scope of the present invention, but it 
is understood that these examples are set forth merely for illustrative 
purposes and that many other compositions are within the scope of the 
present invention.

EXAMPLE I 
For one acre of steep sloping land, the following formula would be used: 
100 lbs. of seed 
350 lbs. of fertilizer 
1,500 lbs. of mulch 
2,500 gallons of water 
Lime as needed, according to soil conditions. Such compositions may be 
sprayed from 150 to 200 feet using conventional equipment. 
EXAMPLE II 
For one acre of rolling land, you would require the following: 
100 lbs. of seed 
350 lbs. of fertilizer 
750 lbs. of mulch 
2,500 gallons of water. 
The forms of invention shown and described herein are to be considered only 
as illustrative. It will be apparent to those skilled in the art that 
numerous modifications may be made therein without departing from the 
spirit of the invention or the scope of the appended claims.