Shade Analysis
Efficient and optimal use of artificial light
The Turfpal Shade Analysis report provides quantitative, as well as a visual representation of the architectural impact on levels of natural photosynthetically active radiation across the playing field of a given stadium/pitch.
In order to achieve our main goal of having an optimal condition on the turfgrass at all times, we need supplementary lighting.
Accurate analysis helps with a much more efficient and optimal way to manage available artificial light units, using them in precise manner, while saving on energy consumption.
When we talk about The Shade Effect, we mean all obstructions between the sun and the turf grass. This can be everything from a tall building to mountains or more often, the stadium/arena itself. This Shade Effect causes a reduction in photosynthesis which in turn reduces the grass’ ability to produce the carbohydrates it needs for growth and development.
The shade stresses cause major problems in the maintenance of good quality turf grass. In modern sport stadiums, reduction of photosynthetic active radiation (PAR) influences significantly durability and performance of a turf surface. Associated with reduced levels of IR-radiance, frequently higher relative humidity, decreased air movement (due to the surrounding stadium), temperature fluctuations with these altered micro-environmental factors influence morphological and physiological grass responses.
With increased shade, a reduction in tiller density, leaf area index, dry weight, quantity of clipped material, and degree of coverage is observed in turf grasses. Furthermore, chlorophyll and carotenoid contents are changing, and root density is decreasing. Regardless of the grass species, the turfgrass needs the correct temperature, light (PAR), humidity and air circulation for optimal growth and recovery.
In the arena type stadiums, which include visual aesthetics and functionality in the most economical way, the roof structures create shade areas up to 90% on the football field in large parts of the year due to geographical locations. To play on healthy and the highest standard surface, one needs to compensate the missing sunlight with artificial light units to provide the most suitable grass growing environment with the light that will provide the useful PAR values and the intensity that can be adjusted according to the needs of the field.
Terminology
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PPF: amount of PAR photons emitted by a light [μmol/s] (Photosynthetic Photon Flux)
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PPFD: amount of PAR photons received by a plant [μmol/s/m^2] (Photosynthetic Photon Flux Density)
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“Standard” PAR (PPFD) = 400-700 nm (For the Growth)
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PAR (Photosynthetically Active Radiation): PAR light is the wavelengths of light within the visible range of 400 to 700 nanometres (nm) which drive photosynthesis. PAR is measured as photosynthetic photon density (PPFD).
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PPFD - measures the amount of PAR that actually arrives at the plant, or as a scientist might say: “the number of photosynthetically active photons that fall on a given surface each second”. PPFD is a ‘spot’ measurement of a specific location on your plant canopy. The units of PPFD are micromoles of photons per square meter per second (μmol/s/m²)
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PPF - measures the total amount of PAR that is produced by a lighting source each second. The unit used to express PPF is micromoles per second (μmol/s).
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DLI - (Daily Light Integral) is usually calculated by measuring the PPFD as it changes throughout the day, and then used to calculate total estimated number of photons in the PAR range received over a 24-hour period for a specific area, usually expressed as moles of light (mol photons) per square meter (m²) per day (d), or: mol/m²/d.
Minimum Light Requirement
Turfgrass species and cultivars vary in their tolerance of shade and light requirements. In this case at Brentford, where cool-season grasses are in use it will be appropriate to focus on cool-season grasses light needs.
Taking recent universities researches, the optimum summer DLI light requirements for cool-season grasses are about 23 Mol/m²/d, where the minimum winter DLI is about 14 mol/m²/d. These values take into account stadium environmental conditions and pitch traffic usage.
The light requirements are less in winter due to the cooler temperatures and the decreased photosynthetic rate of the cool-season grasses. The DLI required to maintain acceptable turf quality also changes with mowing height, with low mown turf requiring a higher DLI (Glenn, 2015).
Assuming an artificial light source delivers an average of 300μmol/s/m² - in a completely shaded place, to reach the daily dose of 23Mol/d/m², it is necessary to radiate for 21 hours a day. It is recommended to not exceed the period of artificial irradiation for more than 24 hours without at least a 6 hours dark break.
Methodology
We have developed a separate method where the Grading shade on the playing field is converted to grids specified with the size to the light footprint of specific single mobile lighting rig unit
Each single grid represents average satellite light measurement with an accuracy of one meter. The PSG software takes satellite PPFD measurements and shows average result, converted to averaged monthly DLI.
The PSG software bases its estimated measurements on specified geographic location with irradiance values based on a 10-year history for the selected location with exact latitude and longitude on the Earth along with the altitude/elevation above sea level. The results are presented as mean daily values on a monthly basis.
Get in touch if you would like an offer to have a Shade Analysis carried out at your stadium.
