New project aims at sustainable substrates

The institute is, together with 8 partners from neighboring countries, dealing with an important problem in the regular (greenhouse) horticulture. With the Interreg-project HortiBlueC, they demonstrate how you can achieve sustainable cultivation substrates with disease-resistant and plant-enhancing properties by using local waste-streams, while at the same time the use of artificial fertilizer, chemical crop protecting agents, and non-renewable materials such as turf and rock wool can be reduced. The (greenhouse) horticulture can be much more sustainable and make important steps in closing its circulations.

In July, Horti-BlueC will start. ILVO plays an important coordinating role, and will focus on the potential of biochar, chitin from shrimps, and plant fiber in new mixtures for cultivation substrates. The focus of the project is not solely on finding solutions to problems but also on the application of those solutions. Bart Vandecasteele (ILVO), project coordinator: “Horti-BlueC has to offer us means that can be used for a successful transition to circular horticulture in practice.”

At present the greenhouse horticulture produces many waste streams that are hard to recycle. One example of this are the cultivation substrates used (400m3 per year), which can contain a high concentration of nutrients and residue of crop protection agents. The resources currently used in cultivation substrates – such as turf, coco fiber, and rock-wool – are subject of discussion due to the impact on environment and climate. Bart Vandecasteele (ILVO): “Turf and rock wool are non-renewable and the production of rock wool costs a lot of energy. And although the use of turf in potting soil has many advantages, its extraction is a threat to pristine turf areas and its sensitive ecosystems and carbon supply. This results in a higher emission of greenhouse gasses.”

Horti-VlueC concretely researches the potential of 5 local waste streams from agriculture, horticulture, agro-feeding sector, fishery sector: plant fiber, used cultivation substrates, crustacean waste and heat from production and burning processes. and the wooden fraction of green waste for compost. These waste streams are present in abundance in the two Sea areas (Belgium, France, The Netherlands, and Great Britain): every year about 70,000 tons of crustacean waste is released, 1.2 million m3 used cultivation substrate, 800,000 tons wooden fraction, 200,000 tons plant fibers, and about 400 kg CO2 emission per hectare of greenhouses.

Crustacean waste (from shrimps) is a source of chitin that can be added to the substrate as an additive. Used cultivation substrate and green waste can be turned into biochar, which is rich in carbon. Both chitin as biochar can improve the fertility of the cultivation substrate and make the plants more resistant against specific leaf and soil diseases. In this way the use of chemical crop protection agents and fertilizers in the greenhouse horticulture can be reduced, and less residue is left behind in the cultivation substrates so they can be recycled after use. The production of biochar releases heat and CO2, which can be used in the greenhouses as a replacement for pure CO2 and heating with fossil fuels. Plant fibers can also be used as bulk material in cultivation substrates.

These insights have been gained during earlier projects. The new thing is that Horti-BlueC combines and demonstrates them in practice. There will be a demo of the use of sustainable, local, cultivation substrates, of the use of chitin and biochar as additives in cultivation substrates, and of a operational installation (ready for commercialization) which can produce both biochar as green energy. Besides, a decision model is being developed, an economical feasibility analysis is conducted, and a cost model is being set up for processing the 5 waste streams. This should stimulate the implementation of new techniques and the percolation of gained insights into practice.

Horti-BlueC is ambitious in its targets. The projects strive for the adoption of new techniques for circular greenhouse horticulture in which 30% less fossil fuels are used, 30% less chemical crop protection agents, 30% less turf and rock wool, and 20% less pure CO2. Bart Vandecasteele (ILVO): "We are aiming to solve the problem points but also of the application of those solutions. By locally developing plant enhancing cultivation substrates based on waste streams, a lot of climate gain can be achieved, and the horticulture can make another step in closing its circulations."

Horti-BlueC involves 9 partners from Belgium, France, the Netherlands, and the United Kingdom: Energieonderzoek Centrum Nederland, Université de Lille, RKS ADAS UK Ltd, Greenyard, Cato Engineering, NIAB EMR, University of Portsmouth, Proefcentrum Hoogstraten, and ILVO as project leader.

Horti-BlueC starts its activities in July 2018 and will finish in 2021. It is being financed by the Interreg 2 Zeeën program 2014-2020, with co-financing by the European Fund for Regional Development under subsidy contract number 2S03-046. ILVO also receives co-financing from the Province of Antwerp and Province East Flanders.