Establishing grass health and condition with one device

The Labosport Redbox simultaneously maps the density and colour of grass surfaces objectively and consistently. The lightweight and easy to operate device improves the ergonomics of testing surfaces and works on any cool or warm season grass type. All numerical and visual data collected is stored in one folder and can be accessed by the client through an app from a client-specific dashboard.

The Normalized Difference Vegetation Index (NDVI) for grass density and grass colour indicates the health condition of both the grass plant and the grass surface. A healthy surface contributes to the game experience, reduces the risk of injury for players and animals, and looks more appealing and entertaining to spectators. A healthy grass surface requires less maintenance and isn’t as reliant on fertilisers or pesticides to maintain its pristine condition or keep it free from pests or infestations.

Three tests integrated into one

The procedures for carrying out the mandatory tests to establish the condition of a pitch are described in the pitch quality manuals that have been issued by the various sports governing bodies around the world. While most of them follow the same assessment procedures, the outcome relies heavily on the subjective assessment made by the testing technician. Establishing NDVI, grass density and grass colour is presently done through three different assessments, each requiring its own testing device and time to set up and execute the test. This makes the testing process demanding and time-consuming.

The Labosport Redbox speeds up the process and delivers objective and repeatable results. The box measures 26 x 26 x 35 centimetres and weighs approximately 2 kg. It incorporates an optical sensor and camera that simultaneously captures all required data at the push of a button. Each time a test is conducted, an area of 30 x 20 centimetres is assessed. “The optical sensor measures the NDVI by generating light waves in the red and near infrared part of the spectrum via LED, and the photodiode then captures the reflected waves and translates the input to measurements,” explains Arnaud Madier, a natural grass technician at Labosport. The reflected light waves indicate the photosynthetically active biomass of the plant, which, in turn, is indicative of the growth the plant is experiencing. The technology has built on the advantages of handheld devices that are currently being used all over the world. “The Redbox has the advantage that measurements that are taken are more stable and always measured from the same distance, which will contribute to the repeatability of the results,” explains Madier. To establish the colour and density of the vegetation, the camera inside the box takes near infra-red (NIR) pictures that establish the transmittance and absorbance by the grass plant as well as red and true-colour pictures to establish its health condition (see side bar). The pictures are stored in JPEG format. “With the camera and sensor firmly and strategically positioned inside the box, the tools are indifferent to external influences or variance in measuring conditions when collecting pictures and data,” Madier adds. All data is stored and analysed by a mini-PC with processing software integrated. “As the box covers the pitch, the picture quality is not affected or influenced by the brightness of the sun or clouds during an overcast day, hence you get a better picture of the true colour of the grass.” The Redbox is activated at the start of the testing session, and each time the button is pressed, it captures the data. This improves the ergonomics of the testing session for the technician, as they no longer have to carry multiple testing devices with them. With all data saved on RAM and collected in one folder for each session, it can also quickly be extracted via a USB connection.

Enabling data-driven maintenance

Grass technicians at the various Labosport offices and affiliated companies around the globe will use the Redbox from this year to establish the grass condition of, for example, football and rugby (stadium) fields, cricket ovals, racecourses and golf greens. It can also be used by individual grass management companies. “Using it in a methodological and repeated way will help you establish the fundamentals like the nutrient status of the plant. The data will help you to fine-tune the nutrient level to

reach peak grass performance and establish when exactly it is time to fertilize again,” Alex Glasgow of the New Zealand Sports Turf Institute points out. The objective measurement of the nutrient status should help minimise wastage or over-application of nutrients and satisfy regulatory requirements. “In most countries around the world, you are required to have a nutrient management plan. The objective data obtained by the Redbox provides evidence of why you are adding fertilisers, especially nitrogen,” he advises. Glasgow notes that the ideal band for nitrogen status is very narrow, hence accurate data is important for making the relevant decisions. “If you have a very good understanding of how the nitrogen status of the plant is changing and you are good in managing it to maintain peak-plant health, this will minimise the chances of disease. If the nitrogen status is too high, you’ll be susceptible to some disease and vice versa if the nitrogen level is too low, you’re susceptible to other diseases.”

Monitoring both progress and decline

Producing a healthy grass surface is a multi-piece jigsaw puzzle and the Redbox makes a major contribution by combining various pieces into one. “The more information you have on the variables you can control, the better the pitch is likely to perform,” Glasgow comments. When establishing new fields, people want to know if things are “on track” to be ready for use at the required time. The Redbox data will accurately track progress and predict the date when full cover will be achieved. Knowing the grass sward condition will be of particular use for stadiums that experience shade. “It will enable mapping the turf sward pattern during the winter months,” Glasgow points out. Mapping how those changes as the season progresses will identify if there is a need to start limiting use to ensure that a suitable quality sward is carried right through the season. “The objective data the Redbox obtains will make it easier to explain to administrators why it is necessary to restrict use or to justify more expenditure than usual to rectify damage to the pitch.”

A pro-active response

As winter conditions can be especially devastating for the health of a grass pitch, an accurate understanding of its condition during that time of the year helps to ensure you have a well-performing pitch at the end of the sporting season when the final outcome for the teams is being determined. “The combination of cold temperatures and lower natural light levels that we experience here in New Zealand, as well as in most European countries, result in the condition of the field declining during that time of the year,” the Technical Director Agronomy of the New Zealand Sports Turf Institute points out. “Winter shade is a big issue that everybody knows about, but it is often hard to convince management to take the appropriate action.” Charles Henderson of PSD Agronomy in the UK agrees with these observations. “The ability to map precisely the turf density or ground exposure and to have objective data on its health will be a major advantage to professional football grounds people and greenkeepers in the UK to create awareness with management.”

Besides being able to respond to extreme weather, Mathieu Léon of Labosport India sees another advantage the Redbox will deliver. “It will certainly help manage the use of water and pesticides as well as fertilisers. The first is increasingly becoming a scarce commodity around the world, while fertilisers have become very expensive in this region. The data will help balance the need for these, while dealing with the pressure of hosting high-profile games.”

Attractive to future-generations

In managing cost, Mathieu Léon foresees the Redbox will also add value to the make-up of the ground care team. “Those who decide to use the Redbox to do their own assessment can now hand the actual field assessment activity to a less experienced employee, freeing up time for the highly educated and well-experienced grounds-person or greenkeeper. This person can now spend more time analysing data, making historical comparisons and matching the required action with the resources, as well as identifying the most suitable time period for undertaking the activity.” Mathieu Léon believes that a more data-driven maintenance approach will also entice new people to join the grass care industry, thus easing the pressures the small group of highly experienced grass care technicians are experiencing. “The younger generation, in particular, have a zest for using data to make improvements. What they lack in experience or “feeling,” they will make up for by quickly identifying issues and matching the correct approach towards these.” The simplicity of its use, the accuracy of its assessments and the repeatability of measurements make the Labosport Redbox an essential tool to achieve a healthy grass pitch, no matter the pressure the grounds care team experiences.

 

What grass colour reveals

The colour of the grass is the first visual indicator of the health condition of the plant. It communicates the environmental conditions the grass experiences, for example, how much sunlight and rain it gets and what the soil is like. Different grass species have different colours and the colour of the grass can change slightly throughout the year. However, as long as the plant is healthy, the colour should be uniform and sustained, and the grass will also look shiny. Conversely, a suffering plant will present a heterogeneous and weak colour.

Grasses commonly used in sports surfaces produce lots of chlorophyll, which absorbs the light needed for photosynthesis to occur. The chlorophyll gives the grass the dark green colour that is often sought. When the grass experiences lots of sun during spring or summer, it might even go a darker green colour. Grass that can no longer extract the right nutrients from the soil will produce less chlorophyll and become yellowish. This can also happen when the grass is overwatered. Grass that is underwatered will often assume a blue-green colour before fading to a yellow-brown colour.

The presence of a red or purple tinge can indicate that the plant is under temperature or nutrient stress. Discolouration can also be due to leaf spot disease activity, where the presence of many leaf spot lesions gives the turf as a whole a different hue.

Leave a Reply