Essential Reinforcement of Natural Grass

More in this section

• Hybrid grass
• Play better and safer
• Resistant and long lasting
• Respect the planet and save money
• Essential Reinforcement of Natural Grass
• Protecting the Synthetic Turf

The innovative hybrid grass POWERgrass against older hybrid grass systems: definition and comparison of the limitations and advantages.

The request for hybrid grass is increasing so it is good to provide a clear definition and differentiate hybrid grass systems from reinforced rootzone systems in natural grass.

It is understood that for reinforced rootzone natural systems in natural grass mean: "the set of methods that use synthetic products to reinforce the rootzone of natural grass".

According to FIFA there four different types of natural grass pitch reinforcements:

• Filled carpet systems: carpet backing with fibres where the natural grass in.
• Fibre systems: fibres and elastic are mixed with soil and natural grass is grown in.
• Hybrid systems: fibres are injected or stitched into the surface and natural grass is grown between the synthetic fibres.
• Net-based systems: net is mixed into the rootzone and grass is grown in.

Filled carpet systems, Fibre systems and Net-based systems have in common that the synthetic reinforcement is buried in the rootzone meanwhile in Hybrid systems the synthetic fibres protrude on the surface where the grass is grown between. All of them increase the stability but have also some drawbacks as for example higher maintenance and renovation costs.

Analysing the etymology of the word “hybrid”, from the agronomic point of view, this term is improper because otherwise there had to be a genetic fusion and this is impossible. However, taking a cue from the automotive industry, it is conventionally accepted the term "hybrid car" for a car powered by two different energy sources such as gasoline and electricity. Taking a parallelism in the sports industry we can define a "hybrid grass" a mixed grass, natural and synthetic, where is possible to play either with or without the natural grass.

According also to FIFA the reinforcements that can improve stability of the pitch even without grass cover are recommended and in that direction has been developed POWERgrass hybrid grass system using a Filled carpet Hybrid system with high density of synthetic fibres protruding on the surface to grant an always playable pitch.

This also coincides with the market demand and it is the concern of many who make an extreme use of the pitch. In little substance, setting a new market standard we can define a Filled carpet Hybrid system: carpet backing with fibres where the natural grass is grown between the synthetic fibres. The system should provide proper growth conditions for natural grass from the very beginning and playable pitch without grass in those cases, for any reason (extreme use, weather conditions or human mistake), the natural grass is possibly damaged.

PowerGrass hybrid turf has also additional innovative features and offers better playing experience and better growth conditions than any other system of natural grass, reinforced or hybrid grass.

The reinforcement of natural grass is not so simple, first you must respect the rules of nature.

The grasses for sports are often cultivated on sand based growth mediums. Those mediums are preferred because they drain easily in case of heavy rainfall during the game and provide 45-55% of porosity with greater amount of meso- and macro-porous where roots, water and biochemical processes are present. The roots provide a support to natural grass plant meanwhile absorb water and nutrients present in the soil water. The nutrients are often applied is salt forms by fertilisation and need to be broken in simple forms that the plants can absorb. To perform their function both roots and useful bacteria (to mineralize the nutrients), need nutrients, water, oxygen and ideal temperature.

In Filled carpet systems, there is backing at 4-5 cm depth and the soil arranged above the backing is not sufficient to develop healthy root growth therefore the roots have to grow also through the backing anchoring also to it, in search of water and nutrients. For that reason it is not possible to use the classic backing in PP to tuft the fibres, then coated with latex or PU, to fasten the fibres to the backing.

Mind that excess of moisture in the soil may occur because of the presence of the wrong backing or because of bad water management. In some cases the excess of moisture associated with a rich biological activity consumes oxygen (O₂) in the soil, giving rise to an anaerobic activity that consumes the little oxygen left from the water (H₂O) and oxides of sulphur (SO₂ and SO₃) thereby releasing hydrogen (H) and elemental sulphur (S). Those two elements form a very powerful acid, a toxic poison, the hydrogen sulphide (H₂S) with a characteristic smell of rotten eggs. The persistence of these conditions results in a fatal poisoning of the grass that becomes red, rootless and dies.

Essential feature for good Filled carpet Hybrid systems

Apply only resilient synthetic fibres to make sure they maintain the upright position during installation and that are also easy to raise during the maintenance operations.

It’s necessary to apply an open backing and bind the fibre-tufts on the backing by different methods like woven grass, light coating, finger coating or hot melt without clogging the backing porosity. The backing has to remain open and soft to prevent surface hardness.

Another important issue regards the selection of the proper growth medium above the below the backing. The sand offers a high porosity growth medium where roots can grow easily, but after a certain number of hours of play, the surface becomes hard and requires decompaction. With the introduction of synthetic fibres in the sand to increase stability, after the first period, the surface becomes even harder and requires decompaction more frequently. The presence of the backing soon or later will contribute to provide surface hardness therefore without proper maintenance the natural grass tends to thin out.

Last but not least the way the system is installed is essential to avoid hardness and reduce future maintenance.

PowerGrass^® hybrid grass is not simply a product, it's a complete system

All details have been subject of reflection and a long study to understand the ideal characteristics of synthetic turf, the growth medium and the system as whole.

Following a long study and direct experience in the field that characterizes the partners involved in PowerGrass group we realized that it is crucial to develop an indivisible set of essential features to provide the ideal Filled carpet Hybrid system by:

1. the use of robust and resilient synthetic fibres and then binding the fibres-tufts to a breathable backing without clogging its porosity is imperative to infill the synthetic turf with sand based growth substrate, by brushing and harrowing the fibres so that they protrude above the surface of 20-30 mm and really protect the natural grass crowns; during the future maintenance is possible to remove the thatch (by scarifying with springs) or all the natural grass (re-turfing) without damaging synthetic fibres;
2. the use of a backing for synthetic turf, not biodegradable, open, with three-dimensional structure, thus breathable evenly across the surface; in details there are other aspects that characterize the synthetic turf backing, equally essential to provide an ideal system for professional games and for the natural grass growth, such as:
• the backing must be soft and flexible at each intersection between the holes, to allow a better interaction of the cleat of the player with the hybrid turf and prevent hardening of the surface;
• the backing must have high porosity for about 320,000 holes interconnected thanks to the three-dimensional structure that prevent water stagnation over the surface and allow gas exchange; at the same time, the size and shape of the holes is such as to a) allow the penetration of the roots from the beginning of the natural grass growth, then reinforce the anchorage of the turfgrass sods that dramatically increases the tear resistance caused by player's slide tackling and b) does not allow sand migration into the backing, to keep open and soft its interior structure;
• finally, the backing must be ladder-proof thanks to its knotted fibres at every intersection so its texture will not come apart upon applied multiple solid tines perforation, necessary to till and aerate the sand growth medium below the backing.

All of these features provide the ideal fabric for an excellent hybrid system, quite unique in the world, protected by 3 international patents and one recent application.

ZOEsand^®, the ideal soil conditioner to get the best outcome from POWERgrass hybrid grass system

An excellent hybrid grass system also requires an ideal sand-based growth medium to optimize sports performance and natural grass growing conditions and the development of the roots above and below the backing.

ZOEsand^® is the result of a long reflection and intuition thanks to a deep knowledge of both worlds: that of natural grass and artificial turf.

ZOEsand^® increases the porosity and moisture content of the sand-based growth medium, provides its isolation proprieties to reduce temperatures variations during hot summers and winter frost, attributes a cushioning effect to the playing surface and reduces soil compaction and the bulk density of the substrate.

The soil conditioner ZOEsand^®, contains coco peat, zeolite sand

Insight

and finally gentle fine cork. Integrate in the growth medium ZOEsand^® is just as important to enhance performance, resistance, duration, reducing dramatically maintenance costs.

• zeolite sand will increase soil fertility by increasing CEC (Cation Exchange Capacity) and will provide a water buffering effect;
• coco peat will restrain moisture and generate humus to increase soil fertility by increasing CEC (Cation Exchange Capacity)in the growth medium to provide carbon to microorganisms for long period;
• gentle fine cork is stable over 60% for about 100 years and is used to balance temperature and air/water content in the growth medium, reduce compaction and provide a softer playing surface;