D e s c r i p t i o n

Field of the invention

The invention relates to hybrid turf, in particular to marking, including line marking, of natural turf surfaces.

Background and related art

In many sports such as soccer or American rules football the playing fields have very precisely defined boundaries and markings. When natural grass is used a groundskeeper or gardener needs to paint these markings on a field. This can be time consuming and can add to the expense of maintenance of a field or turf surface made from natural grass plants.

United States patent US 6,227,989 B1 discloses a line marking system for installing permanent field lines in a natural grass field. The system comprises a line fixed to a backing sheet which is installed under the grass sod. The backing sheet is preferably a mesh which allows the grass to grow through the backing sheet thereby anchoring the line to the ground. The line once affixed to the backing sheet completely blocks out sunlight. This prevents grass from growing through the backing sheet and intermingling with the line.

German patent application publication DE 197 48 486 A1 discloses a method of making visible markings in natural grass surfaces. A holding strip is placed in a trench, which is then filled with loose material. Filaments are then inserted into the holding strip through the loose material. The Filaments are held in place by the bottom strip, for example by a staple gun. The filaments have a color in contrast with the surrounding grass.

Summary

The invention provides for a turf surface, an artificial turf visual marking element, and a method in the independent claim. Embodiments are given in the dependent claims.

Many players and coaches prefer to play sports on a natural turf surface. The use of field lines made from artificial turf that block the sun may introduce discontinuities or changes in the turf surface that may have a negative effect on the athletic

performance of an athlete or may even interfere with the trajectory of a ball when it comes into contact with a marking on the turf surface. A line made from artificial turf within a natural grass field could also be a hazard. An athlete's cleats may be more likely to catch or bind on an abrupt transition to artificial turf and could possibly result in injury of the athlete. Embodiments may provide for a durable means of marking a turf surface that minimizes the changes to the playing surface. Embodiments may use hybrid turf portions to provide line markings within an otherwise natural turf surface. Hybrid turf as used herein encompasses a backing with artificial turf fibers attached that permits the growth of natural grass plants between the artificial turf fibers. The hybrid turf portion may be constructed by burying an artificial turf marking element within the natural turf. The artificial turf marking element comprises an artificial turf backing with pores or holes which permit the growth of natural grass plants between contrasting artificial turf fibers. The contrasting artificial turf fibers provide a visual contrast to the natural grass plants and for visual marks on the turf surface. In addition to the region where the artificial turf fibers are located, the artificial turf backing also comprises a structural support region. The structural support region lacks the contrasting artificial turf fibers. Natural grass plants also grow over the structural support region and help to anchor the artificial turf marking element and may also help to make the natural turf more durable.

In one aspect the invention provides for a turf surface. The turf surface for example may be in some examples a sport or playing field. The turf surface comprises one or more natural turf portions comprising natural grass plants that form a natural turf surface and at least one hybrid turf portion comprising an artificial turf visual marking element and the natural grass plants. The natural grass plants encompass living grass plants that may also be referred hereunto as grass. Hybrid turf portion may be a hybrid turf that comprises both natural grass plants and artificial turf elements that are combined. The artificial turf visual marking element comprises an artificial turf backing. The artificial turf backing is divided into at least one visual marking region and a structural support region. The structural support region is a label used to indicated a portion of the artificial turf backing that does not have the contrasting artificial turf fibers. The structural support region at least partially surrounds each of the at least one visual marking region. The artificial turf backing comprises holes throughout the visual marking region. The artificial turf backing comprises the holes throughout the structural support region. The natural grass plants of the hybrid turf portion comprise roots growing through the holes.

In different examples the artificial turf backing may take different forms. For example in some instances the artificial turf backing may be a woven fabric or other fabric made from fibers. The holes may be the natural spaces between the fibers making up the artificial turf backing. In other cases the artificial turf backing may be made from a plastic or other solid material that has the holes for the roots punched or cut through them. The term hole as used herein encompasses an opening that is large enough for grass roots to grow through. The holes may take different forms. As mentioned above the holes can be the spaces between woven or non woven fibers of a fabric. The holes can also be opening or slits punched or cut in a plastic or solid material. The artificial turf visual marking element further comprises contrasting artificial turf fibers attached to the artificial turf backing only within the visual marking region. The contrasting artificial turf fibers provide a visual contrast to the natural grass plants within the visual marking region and the support region. That is to say the

contrasting artificial turf fibers are used to provide a visual marking which is visible with respect to the natural grass plants.

This embodiment may be beneficial because it may provide for a means of providing for markings on the turf surface which do not need to be renewed periodically. For example in football, soccer or other sports fields in natural turf surfaces a grounds keeper or a gardener needs to repaint lines on the playing field at regular intervals such as before a weekly game. This can be extremely time consuming and requires great care to ensure that the lines are in the proper position every time. Additionally, for some sports teams, it may be desirable to have logos, numbers or other lettering which is present on the natural turf. This however may also be difficult to do regularly because it is extremely labor intensive. The artificial turf visual marking elements may therefore provide for markings or graphics on the turf surface which do not need to be renewed. The combination of the natural grass plants within the artificial turf visual marking element has the benefit of providing for a visual marking that still retains many of the properties of a natural grass surface.

In another embodiment, the holes are pores in the artificial turf backing.

In another embodiment the holes have a diameter that is less than 10 mm in diameter. In this embodiment, the diameter of the holes is greater than any one of the following: 6 mm, 4 mm, and 3 mm. This embodiment may be beneficial because it may enable earthworms to travel through the holes and enable aeration of the portion of the turf surface which includes the artificial turf visual marking element. In the above embodiment the holes are described as having a diameter it is understood that holes do not have to have a round shape. The "diameter" of a hole is descriptive of the size of a round or cylindrical object which can pass through the hole. For example the holes having a "diameter" of 10 mm means that a round object with a diameter of more than 10 mm will not pass through the hole. In this embodiment the term "diameter" can be substituted with term the "diameter of the largest circle that fits within the opening of the hole." It is understood that this largest circle lies in the same plane as the opening. This measurement of the size of a hole is reasonable since it is for determining if an earthworm would fit through the hole or not. The restriction of the hole diameter to below 10 mm or below may be beneficial because making the holes too large may reduce how well the grass roots hold the artificial turf backing.

In another embodiment, the structural support region consists of natural grass plants. In this embodiment the structural support region only has natural grass plants in the structural support region. The structural support region lacks artificial turf fibers. In this embodiment the structural support region serves to further attach the artificial turf visual marking element using the roots of the grass plants growing in the structural support region.

In another embodiment, the artificial turf backing consists of a single base layer.

In another embodiment, wherein the artificial turf fibers are tufted into the artificial turf backing.

In another embodiment the artificial turf visual marking element further comprises green artificial turf fibers attached to the artificial turf backing within the structural support region. This may be beneficial because it may provide for a transition from the artificial turf visual marking element to the surrounding natural turf portions of the turf surface. This may also provide for more robust artificial turf visual marking elements, because there are a greater number of artificial turf fibers, that are for example more secure and therefore less susceptible to damage.

In another embodiment, the green artificial turf fibers are tufted to the artificial turf backing.

In another embodiment a density of the green artificial turf fibers within the structural support region decreases with increasing distance from the visual marking region. This embodiment may be beneficial because the density of artificial turf fibers versus the density of the natural grass plants is gradually transitioned. This may provide for a more natural appearance to the turf surface as well as providing for an artificial turf visual marking element which is better secured to the ground or base. In another embodiment a density of the holes within the structural support region increases with increasing distance from the visual marking region. The holes provide access to the roots of the natural grass plants. Increasing the density of the holes within the structural support region as the distance increases from the visual marking region provides a means to better secure the edges of the artificial turf backing. The increase in the density of the holes may also facilitate an increase in the density of the natural grass plants near the edges of the artificial turf backing. This may additionally provide for a better attachment of the artificial turf backing to the ground. In another embodiment the contrasting artificial turf fibers are colored any one of the following colors: red, orange, cyan, blue, violet, light green, black, grey, white, blue- green, black, orange, light blue, pink, Day-Glo green, light green, dark green, and combinations thereof. The use of these colors may be beneficial because they may provide for optical contrast between the natural grass plants and the artificial turf visual marking element.

In another embodiment the artificial turf visual marking element comprises any one of the following: a number, a letter, a Chinese character, a Kanji character, a Kana character, a picture, a graphical display, and combinations thereof. This

embodiment may be beneficial because it may provide for a means of durably putting any one of these visual markings onto the turf surface.

In another embodiment the turf surface is a sport or playing field. This embodiment may be beneficial because artificial turf markings such as lines or other indicators are often necessary for a sport to be played properly.

In another embodiment the turf surface is any one of the following: a rugby field, a field hockey field, an American rules football field, a Gaelic rules football field, an Australian rules football field, a soccer field, a football field, a cricket pitch or field, a baseball diamond, and a field sport field.

In another embodiment the artificial turf visual marking element is any one of the following: a line marking, a sideline, a boundary line, and a sideline.

In another embodiment the support region is an entire goal region. This embodiment may be beneficial because around the goal region in a sports field there is typically high foot traffic which results in high wear of the natural turf which results in thinning of the natural turf. Using the hybrid turf within the goal region may provide for a more robust natural turf surface.

In another embodiment the turf surface is a soccer field. In another embodiment the artificial turf visual marking elements comprise any one of the following: a touchline, a sideline, a boundary line, a goal region, a goal line, a penalty spot, a center spot, a center circle, a corner arc, a half-way line, a penalty arc, and combinations thereof. A turf visual marking element according to any one of the following may be beneficial because it may provide an efficient means for permanently marking a soccer field. A penalty mark as used herein also

encompasses the term commonly known as an 1 1 -meter line.

In another embodiment the structural support region comprises any one of the following: an entire goal box, an entire penalty box, an entire interior of a center line, an entire interior within a penalty arc, an entire interior within a corner arc, and combinations thereof. This may be beneficial because any one of these regions may be high foot traffic which results in high wear of the natural turf which results in thinning of the natural turf and this may provide for a more durable turf surface. It should be noted that a goal box is sometimes referred to as a 6-yard box. A penalty box is sometimes referred to as an 18-yard box.

In another embodiment the turf surface is an American rules football field. In another embodiment the artificial turf visual marking element is any one of the following: a goal line, a yard line, an end line, a limit line, a sideline, a sideline hash mark, an in field hash mark, a conversion line, a conversion hash mark, a field yard line number, and combinations thereof. This embodiment may be beneficial because it may provide for an efficient means of permanently marking an American rules football field.

In another embodiment the structural support region comprises the entire end zone, a sideline region, and combinations thereof. This embodiment may be beneficial because the end zone or the sideline may be particularly high foot traffic which results in high wear of the natural turf which results in thinning of the natural turf and this may provide for a more robust turf surface.

In another embodiment at least one hybrid turf portion comprises less than 1 % of the turf surface.

In another embodiment at least one hybrid turf portion comprises 5% or less of the turf surface. In another embodiment at least one hybrid turf portion comprises 10% or less of the turf surface.

In another embodiment at least one hybrid turf portion comprises 50% or less of the turf surface.

In another embodiment the structural support region comprises 10% or less of the artificial turf backing.

In another embodiment the structural support region comprises 25% or less of the artificial turf backing.

In another embodiment the structural support region comprises 50% or less of the artificial turf backing. In another embodiment the structural support region comprises 75% or less of the artificial turf backing.

In another embodiment the structural support region extends no further than 1 cm from the at least one visual marking region.

In another embodiment the structural support region extends no further than 5 cm from the at least one visual marking region.

In another embodiment the structural support region extends no further than 10 cm from the at least one visual marking region.

In another embodiment the at least one structural support region extends no further than 25 cm from the at least one visual marking region. In another embodiment the structural support region extends no further than 50 cm from the at least one visual marking region.

In another embodiment the artificial turf backing comprises any one of the following: a woven fabric, a plastic material with punched holes, and a non-woven fabric. The non-woven fabric and the woven fabric may have holes due to the textile nature of their construction.

In another embodiment the contrasting artificial turf fibers and/or the green artificial turf fibers are attached to the artificial backing by any one of the following: tufting, weaving, and gluing.

In another aspect the invention provides for an artificial turf visual marking element for marking a natural turf surface. The artificial turf visual marking element comprises an artificial turf backing. The artificial turf backing is divided into at least one visual marking region and a structural support region at least partially surrounding each of the at least one visual marking regions. The artificial turf backing comprises holes throughout the visual marking region. The artificial turf backing comprises the holes throughout the structural support region. The natural grass plants of the hybrid turf portion comprise roots growing through the holes. The artificial turf visual marking element further comprises contrasting artificial turf fibers attached to the artificial turf backing only within the visual marking region. The contrasting artificial turf fibers provide a visual contrast to the natural grass plants or natural turf within the visual marking region and the support region.

In another embodiment the artificial turf visual marking element further comprises green artificial turf fibers attached to the artificial turf backing within the structural support region. In another embodiment the density of the green artificial turf fibers within the structural support region decreases with increasing distance from the visual marking region.

In another embodiment a density of the holes within the structural support region increases with increasing distance from the visual marking region.

In another embodiment the contrasting artificial turf fibers are colored according to any one of the following colors: red, orange, cyan, blue, violet, light green, black, grey, white, blue-green, black, orange, light blue, pink, Day-Glo green, and combinations thereof.

In another embodiment the artificial turf backing comprises any one of the following: a woven fabric, a plastic material with punched holes, and a non-woven fabric. In another embodiment the contrasting artificial turf fibers and/or the green artificial turf fibers are attached to the artificial turf backing by any one of the following:

tufting, weaving, and gluing.

In another embodiment the structural support region comprises 10% or less of the artificial turf backing.

In another embodiment the structural support region comprises 25% or less of the artificial turf backing. In another embodiment the structural support region comprises 50% or less of the artificial turf backing.

In another embodiment the structural support region comprises 75% or less of the artificial turf backing.

In another embodiment the structural support region extends no further than 1 cm from the at least one visual marking region. In another embodiment the structural support region extends no further than 5 cm from the at least one visual marking region.

In another embodiment the structural support region extends no further than 10 cm from the at least one visual marking region.

In another embodiment the structural support region extends no further than 25 cm from the at least one visual marking region.

In another embodiment the structural support region extends no further than 50 cm from the at least one visual marking region.

In another aspect the invention provides for a method of installing an artificial turf visual marking element in a natural turf surface. The artificial turf visual marking element is according to an embodiment. Installation may occur into an existing natural turf surface, or it may occur prior to the planting and establishment of the natural turf surface. Both cases may be infilled onsite. Alternatively the infilling may occur offsite, and the natural turf seeded and established offsite, and then the finished product is installed onsite and made ready for play The method comprises digging an opening in a natural turf surface. For smaller regions the opening could for example be a trench. An alternative to trenching is excavating or stripping, particularly for larger areas. For example larger areas could be excavated or stripped using a machine that is typically, not always, designed to remove larger areas of natural turf. The method further comprises placing the artificial turf visual marking element in the trench or opening. The method further comprises infilling or burying the artificial turf backing in the trench or opening. The natural grass plants may then grow over the area that was just buried in the trench or opening. This may be accomplished for example by the region that was formerly the trench or opening being seeded with grass seed or the grass may naturally spread over the course of time to fill in the open spots or exposed dirt that are in the former trench or opening. In another embodiment the artificial turf backing has an underside. The underside comprises a linear alignment marking. The artificial turf visual marking element is rolled. The method further comprises marking a straight line in the trench or opening. The method further comprises placing the artificial turf visual marking element in the trench or opening. The method further comprises unrolling the visual marking region in the trench or opening such that the linear alignment marking is aligned with the straight line. This embodiment may be beneficial because it may be difficult to initially align the visual marking element properly on a sport field. If at least one hybrid turf portion comprises a line or a marking on its underside and is rolled, the person installing the hybrid turf portion can easily align an alignment mark on the underside with a mark in the trench or opening. This may be suitable for performing the initial alignment or even the final alignment of the artificial turf visual marking element with the turf surface.

It is understood that one or more of the aforementioned embodiments of the invention may be combined as long as the combined embodiments are not mutually exclusive.

Brief description of the drawings

In the following embodiments of the invention are explained in greater detail, by way of example only, making reference to the drawings in which:

Fig. 1 illustrates an example of an artificial turf visual marking element;

Fig. 2 illustrates an example of a turf surface;

Fig. 3 illustrates a further example of an artificial turf visual marking element;

Fig. 4 illustrates a further example of an artificial turf visual marking element; Fig. 5 illustrates a further example of an artificial turf visual marking element; Fig. 6 illustrates a further example of an artificial turf visual marking element; Fig. 7 illustrates a further example of an artificial turf visual marking element; Fig. 8 illustrates a further example of a turf surface;

Fig. 9 illustrates a natural grass turf surface before installation of an artificial turf visual marking element;

Fig. 10 illustrates an opening dug in the natural grass turf surface of Fig. 9;

Fig. 1 1 illustrates the placement of an artificial turf visual marking element in the opening of Fig. 10;

Fig. 12 shows the an artificial turf visual marking element of Fig. 1 1 after the

opening has been backfilled;

Fig. 13 illustrates an example of a turf surface that incorporates artificial turf visual marking elements;

Fig. 14 illustrates a further example of a turf surface that incorporates artificial turf visual marking elements;

Fig. 15 illustrates a further example of a turf surface that incorporates artificial turf visual marking elements; and

Fig. 16 illustrates a further example of a turf surface that incorporates artificial turf visual marking elements.

Detailed Description

Like numbered elements in these figures are either equivalent elements or perform the same function. Elements which have been discussed previously will not necessarily be discussed in later figures if the function is equivalent.

Fig. 1 shows an example of an artificial turf visual marking element 100. The artificial turf visual marking element 100 comprises an artificial turf backing 102. The artificial turf backing can be divided into a visual marking region 104 and at least one structural support region 106 which may at least partially surround the visual marking region 104. The artificial turf visual marking element 100 illustrated in Fig. 1 shows a cross-sectional view. The artificial turf visual marking element 100 may for example be used to make a line marking on a sport or athletic field. The artificial turf backing 102 is shown as having an underside 108 and a top 10. Within both the structural support region 106 and the visual marking region 104 it can be seen that there are a number of holes 1 12. The holes 1 12 may depend upon the type of artificial turf backing 102. For example the artificial turf backing 102 can be made from a solid material such as a sheet of plastic or other polymer material. In this case the holes 1 12 could be little holes punched or cut in the artificial turf backing 102. In other examples the artificial turf backing 102 may be a woven or non-woven textile material. The space between the fibers making up the artificial turf backing 102 in that case would then form the holes 1 12. The holes 112 allow clearance or the passage of roots from grass plants through the holes 1 12. On the top 1 10 it can be seen that there are a number of contrasting artificial turf fibers 1 14. The artificial turf fibers 1 14 may be contrasting such that they have a high visual contrast with natural grass plants.

Fig. 2 shows an example of a turf surface 200 that has been constructed by burying the artificial turf visual marking element 100 within natural turf. The turf surface 200 can be shown as comprising a natural turf portion 202 and a hybrid turf portion 204. The hybrid turf portion 204 was formed by burying the artificial turf visual marking element 100 of Fig. 1 within the earth 210. As illustrated in Fig. 1 the artificial turf backing 102 has a number of holes 1 12. In this example the natural grass plants 206 have a root structure 208 that grows through the holes 1 12. It can be seen that there are natural grass plants 206 growing throughout the hybrid turf portion 204. The growth of the foot structures 208 through the holes 1 12 helps to anchor the artificial turf visual marking element 100 within the earth 210. The contrasting artificial turf fibers 1 14 provide a visual contrast to the natural grass plants 206. This enables a permanent marking or graphics within the turf surface 200.

Fig. 3 shows a further example of an artificial turf visual marking element 100. The design shown in Fig. 3 is a variation of the design illustrated in Fig. 1. In this example again a cross-section of the artificial turf visual marking element 100 is shown. However, in this example the structural support region 106 only borders one portion of the visual marking region 104. The example shown in Fig. 3 may for example be useful in placing the artificial turf visual marking element 100 near a wall or other structure. The visual marking region 104 could for example be placed directly against a wall or other structure. In other instances it may not be necessary to have the structural support region 106 on both sides. For example at a side or end line one side may receive much less foot traffic or damage due to the playing of a sport.

The artificial turf visual marking element 100 shown in Fig. 3 can be used in the same way as is illustrated in Fig. 2.

Fig. 4 shows a further example of an artificial turf visual marking element 100. The artificial turf visual marking element 100 shown in Fig. 4 is a modification of the artificial turf visual marking element 100 illustrated in Fig. 1. In this example the holes 1 12 increase in frequency as the distance from the visual marking region 104 increases. This may be beneficial because it may provide more places for the roots, as illustrated in Fig. 2, to grow through the holes 1 12. This may provide better anchoring of the artificial turf backing 102 within the earth 210 as is shown in Fig. 2. The artificial turf visual marking element 100 shown in Fig. 4 may be substituted for the artificial turf visual marking element illustrated in Fig. 2.

Fig. 5 illustrates a further example of an artificial turf visual marking element 100. The artificial turf visual marking element 100 shown in Fig. 5 is similar to the design shown in Fig. 1. The design shown in Fig. 5 differs from that shown in Fig. 1 in that there are green artificial turf fibers 500 which are shown as being attached to the artificial turf backing 102 within the structural support regions 106. The addition of the green artificial turf fibers 500 may increase the durability of the turf surface in the vicinity where the artificial turf visual marking element 100 has been installed. The artificial turf visual marking element 100 shown in Fig. 5 may be installed into the earth 210 as is shown in Fig. 2.

Fig. 6 shows a further example of an artificial turf visual marking element 100. The artificial turf visual marking element 100 shown in Fig. 6 is a modification of the design illustrated in Fig. 5. In this example the visual marking region 104 is only surrounded on one side by the structural support region 106. The design shown in Fig. 6 is analogous to the design illustrated in Fig. 3. Fig. 7 shows a further example of an artificial turf visual marking element 00. The design illustrated in Fig. 7 is a modification of the design illustrated in Fig. 5. In Fig. 7 the density of the holes 1 12 increase as the distance from the visual marking region 104 increases. It can be seen that near the ends or borders of the structural support region 106 the density of holes has increased greatly. In this example also, the density of the artificial green turf fibers decreases as the distance from the visual marking region increases. In the example shown in Fig. 7 this has the effect as the distance increases from the visual marking region the amount of natural grass plants will increase. There will therefore be a gradual transition from artificial turf fibers to natural grass plants. This may be beneficial because the transition from the artificial turf fibers to natural grass plants will be gradual and less noticeable to players as well as to spectators viewing the turf surface. The design shown in Fig. 7 is analogous to the design illustrated in Fig. 4. Fig. 8 illustrates a turf surface 200 formed using the artificial turf visual marking element 100 from Fig. 7. Fig. 8 is analogous to Fig. 2. In Fig. 8 it can be seen that the artificial turf visual marking element 100 has been partially buried within the earth or ground 210. The turf surface 200 comprises a natural turf portion 202 and a hybrid turf portion 204. The hybrid turf portion 204 was formed by burying the artificial turf visual marking element 100 of Fig. 7. Examining the surface it can be seen that there is a region indicated by the visual marking region 104 where the contrasting artificial turf fibers 1 14 will be clearly visible. There is also a region where there is a mixture of green artificial turf fibers 500 and natural grass fibers 206. Near the edges of the artificial turf backing 102 within the structural support region 106 the density of the green artificial turf fibers 500 gradually decreases. It can be seen that there is an increase in the number of natural grass plants 206. This provides for a smooth transition from a mixture of natural grass plants 206 and the artificial turf fibers to just the natural grass plants 206 within the natural turf portion 202. Additionally in this example, within the artificial turf backing 102 the density of the holes 1 12 increases. The root structure 208 of the natural grass plants 206 then is also able to better anchor the artificial turf backing 102.

Figs. 9-12 illustrate a method of fabricating the turf surface 200 illustrated in Fig. 2. The method illustrated in Figs. 9-12 also equally apply to the use of the artificial turf elements 100 shown in Figs. 3, 4, 5, 6, and 7. Fig. 9 illustrates the initial step or start of the method. In this step there is just a plane natural turf 200 that consists of natural grass plants 206 growing in the ground or earth 210. The root structure 208 of the natural grass plants 206 can be shown as growing throughout the ground 210.

Fig. 10 illustrates the next step of the step. The next step is to dig 1000 an opening 1004. In this example, the opening is a trench. On either side of the opening 1004 can be shown the natural grass plants 206. In some versions of the method there may be an optional straight line 1002 which may be used for aligning the artificial turf visual marking element 100 as it is unrolled.

Fig. 1 1 illustrates the next step. In Fig. 1 1 the next step is to place 1 100 the artificial turf visual marking element into the opening 1004. Fig. 12 illustrates the next step in the method. In Fig. 12 the next step is to fill 1200 the opening. The opening is no longer present and in its place there is backfill material 1202. In Fig. 12 the natural grass fibers 206 have not grown over the artificial turf backing 102. This could be accomplished for example by sowing grass seed over the artificial turf backing 102 within the backfill material 1202 or it could be achieved by natural growth and spreading of the natural grass plants 206 over the artificial turf backing 102. The backfill material 1202 may for instance be any material in which natural grass plants 206 can grow. Typically a mixture of soil and sand will promote healthy natural grass plants 206. After the grass has grown over where the opening was and has grown in between the contrasting artificial turf fibers 1 14, the method will result in the turf surface 200 shown in Fig. 2.

Fig. 13 illustrates an exemplary turf surface 200 that is in the form of a soccer field. Figs. 14-16 show further variations of the example illustrated in Fig. 13. The examples illustrated in Figs. 13-16 also apply to playing fields or turf surfaces for other sports such as field hockey or American football. The field shown in Fig. 13 is shown as having markings for a touchline 1300, a center line 1302, a center spot 1304, a center circle 1306, two goal lines 1308, two goal boxes 1310, two penalty boxes 1312, two penalty arcs 1314, two penalty spots 1316, and four corner arcs 1318. The portions of the turf surface 200 which are just natural grass are indicated as being the natural turf portion 202. In this example it can be seen that the natural turf portion 202 makes up almost the entire turf surface 200. All of the above structures and lines mentioned are surrounded by dotted lines which are used to indicate the position of the hybrid turf portion 204. In the example of Fig. 13 then, all of the field markings are made using a minimal amount of the artificial turf elements 100. This preserves the natural feel and playing effect of using a natural turf surface. However, the artificial turf elements 100 provide long lasting markings for all of the above mentioned markings. This reduces greatly also the amount of maintenance needed before a game is played on the turf surface 200. Fig. 14 illustrates a further example of a turf surface 200. In this example the only hybrid turf portion 204 is a graphic in the center of the playing field. It can be seen that there is a large region of the hybrid turf portion 204 surrounded by the natural turf portion 202. This example may be beneficial when it is desired by the team to add a graphic or logo in the center or other portion of the playing field. The adding of a graphic may be much more labor intensive than simply adding lines or markings on the field. This may provide for a superior aesthetic to the field while reducing the costs of adding a graphic or logo.

Fig. 15 shows a further example of a turf surface 200. In this example only the goal box 1310 is made from the hybrid turf portion 204. In this example the entire goal box 1310 is made from hybrid turf. The interior region of the goal box 1310 is the structural support region 106. Within the goal box 1310 there is therefore a mix of both natural grass plants and artificial turf fibers. This may be beneficial because in the vicinity of the goal there is a larger amount of foot traffic and there may be more damage to the turf surface 200. This may provide for a means of not only marking the location of the goal box 1310 but also providing for a more robust and less maintenance of the turf surface 200. Fig. 16 shows a variation of the design shown in Fig. 15. Except in this example the entire region encompassed by the penalty arc 1314, the penalty spot 1316, the penalty box 1312 and the goal box 1310 are made from the hybrid turf portion 204. The rest of the field is made from the natural turf portion 202. The majority of the hybrid turf portion 204 in this example is the structural support region 106. This may be beneficial because the structural support region with or without green artificial turf fibers may provide for better wear and tear of the region surrounding the goal.

The examples illustrated in Figs. 13-16 may be mixed or matched as long as they are not mutually exclusive. Likewise, the artificial turf elements 100, as illustrated in Figs. 1 , 3, 4, 5, 6, and 7 may be used to construct the examples shown in Figs. 13- 16.

List of reference numerals

100 artificial turf visual marking element

102 artificial turf backing

104 visual marking region

106 structural support region

108 underside

110 top

112 holes

114 contrasting artificial turf fibers

200 turf surface

202 natural turf portion

204 hybrid turf portion

206 natural grass plants

208 root structure

210 ground

500 green artificial turf fiber

900 start of method

1000 dig opening

1002 optional straight line

1004 opening

1100 place artificial turf visual marking element into the opening

1200 infill opening

1202 backfill material

1300 touch line or side line

1302 centerline

304 center spot

1306 center circle

1308 goal line

1310 goal box 1312 penalty box

1314 penalty arc

1316 penalty spot

1318 corner arc