Through sand channels, we want to get nutrients into the soil at greater depth'
Growth medium compost as the basis for a good turf
On the road to chemical-free management, VGR is developing a maintenance method that consists of cultivation techniques and natural soil-improving products. The slogan is: soil as the basis for a good turf. VGR is therefore working on trials with compost as the basis for good soil. Golfclub Midden-Brabant, one of VGR's original customers, is involved in one of these trials, in which the VGR product Groeigoed is applied to a green and the tees to improve the quality of the turf.
For twenty years VGR has been using a combination of appropriate precision mechanical treatments and natural soil improvement products to develop a chemical-free maintenance method that also requires less fertilization and watering. The compost product Groeigoed is part of this method, which is continuously under development.
Groeigoed
The Groeigoed products consist of composted green waste and are produced at the VGR location in Almkerk, the Netherlands. The VGR Group consists of three mutually reinforcing units: VGR Composting, VGR Equipment and VGR Services. The green maintenance activities of VGR Equipment, mainly on sports facilities, generate green waste streams. VGR Composting facility processes these to new soil improvement products and wood shreds. These products are used by VGR Equipment to improve the growing conditions of the green areas that are to be maintained.
The Groeigoed compost is dried in a natural way in Almkerk and enriched and stabilized by fermentation. A fine Groeigoed fraction is used for lawns, and a coarser fraction for sports fields. Both Groeigoed products are fully matured. Once the dry material is injected into the soil by the Topchanger, it is gradually converted by the soil life into nutrients that can be absorbed by grass plants. 'Composting is an organic process that provides a natural means of improving soil resistance and grass plant growth,' said Arwin Verschoor, soil specialist at VGR.
'Composting is an organic process, which provides a natural means of improving soil resistance and grass plant growth'
Customer from the very beginning
At Golfclub Midden-Brabant, the VGR TopChanger has already injected Growth Goods at depth into the soil on several occasions. This golf course became a customer just after VGR was founded, twenty years ago. Verschoor started with dethatching and aeration, and later expanded the activities to include cleaning ditches and pond edges and overseeding bare areas. In recent years, VGR has been scarifying the course with the contoured Maredo MT200 Flex verticutter.
Head greens keeper Koen Verhelst, also working for Golfclub Midden-Brabant for almost twenty years, explains how the Groeigoed products are applied on this golf course. 'On the tees, we repair the playing damage on the divots every week with a mixture of sand and Groeigoed.' Ruud de Deugd, who worked with Verhelst from VGR: 'In the green of hole 4 we injected a mixture of 95% sand and 5% VGR Groeigoed, very fine, high-quality compost (1-2 mm). By injecting this stable organic matter, we are trying to get the food web of soil life going, to make the soil more resilient.' The ratio of the mixture with Groeigoed compost can be adjusted to suit. Verhelst has already told us that the germination of the grass is good and the dehydration of the seedlings is low because the compost retains moisture.
Trial on green 4
In 2019, a trial began on a green 4 at Golfclub Midden-Brabant, together with VGR and consultant Casper Paulussen. At a depth of 10 to 15 cm, a mixture of sand and a fine fraction of matured Groeigoed compost, which was specially developed for golf greens, was injected. When this course was laid out twenty years ago, the greens consisted of 100 percent sand. We noticed that they were subject to considerable leaching as a result. As a result, the CEC is extremely low in this green. In the top layer, the organic matter content is fine, but at a depth of 1.10 m it is low, less than 2 percent. Through the sand channels that the TopChanger creates to reach further into the soil, we want to get nutrients into the soil at a greater depth. By creating a more active soil life, we want to allow the thatch layer to break down naturally. Green 4 suffers a lot from dollar spot. With the fungi and bacteria from the compost, we want to strengthen the grass plant in the fight against diseases and ensure a faster recovery of dollar spot. We have to be patient to see results. This kind of development is gradual and must be done meticulously, in conjunction with the fertilization schedule Paulussen wrote for us. Because of the injection and aeration with the TopChanger, we can apply compost to only 3 percent of the green area. So it takes several turns of tilling to get compost into the soil over the whole green. Golfclub Midden-Brabant wants to continue this trial on green 4 until approximately 2023. Through the application of compost, we hope to eventually have to apply less fertilizer and use less water and pesticides.' Because there was a lot of damage from grubs on the fairway in 2020, the golf club, on the advice of advisor Ernst Bos, is also going to work with compost there.
By introducing stable organic matter, we are trying to get the food web of soil life going'.
Synergy
Verschoor puts the fact that only 3 percent of the total green area can be covered in compost into the right perspective: 'The difference between 3 percent and nothing is a lot. The advantage of enriching every 3 percent with compost is not only the added 3 percent, but also the progressive effect through the synergy that is created in the soil. As the bacteria and fungi in the compost do their work, the activity of the soil life goes up considerably and increases the soil resistance. It brings the soil back into balance and the turf benefits from that.'
This article was written by Karlijn Raats (NWST) and published in the magazine Greenkeeper.
