Peter van Bodegom about sustainable horticulture

In recent months, greenhouse growers - but not only they - were once again confronted with the facts. As a result of geopolitical developments, the price of gas quadrupled. This made it all the clearer that greenhouse horticulture must look for other sources of energy. A number of companies have already switched to geothermal energy (heat from deep underground), others are experimenting with the temporary storage of (solar) heat.

Prolonged drought

"Another challenge is the greater probability of prolonged drought as a result of climate change," says Van Bodegom, professor of environmental biology at Leiden University's Institute of Environmental Sciences. 'How to ensure the availability of sufficient, fresh water during those periods? In addition, the sector still has to deal with leakage of pesticides into ground and surface water. The environmental pressure that this causes calls for more sustainable crop protection, for example, by making even greater use of biological control."

The latter ties in nicely with another challenge to improve biodiversity in the greenhouse area. Many horticulturalists prefer to see a strictly mown green belt around their greenhouses because they are afraid that a lusher vegetation will lead to more insect pests in the greenhouse. Van Bodegom: "We are working with a Community of Practice of greenhouse farmers to develop an alternative to the short-mown grass. With which vegetation can we promote a functional biodiversity of species that attract pest controllers? Very interesting. The horticulturists are experimenting, real field trials in other words, and our students will be evaluating the impacts."

Export of innovations

The underlying question in these is where we want to go with Dutch greenhouse horticulture. Van Bodegom: "The sector is now a supplier of bulk products, such as tomatoes, cucumbers and peppers, mostly for export. It is also an exporter of innovations, i.e. new varieties and smart technical systems. The question is whether it can continue to fulfil both roles. I can imagine that the sector chooses to become the testing ground of the world by focusing on developing and exporting sustainable innovations and knowledge, while bulk production takes place elsewhere."

When we ask him what greenhouse horticulture in Holland will look like in ten years' time, Van Bodegom says, he doesn't want to pin himself down on one scenario. "However, there are a number of themes that keep recurring. I have already mentioned energy, water, the environment and biodiversity, but also the question of how we can grow even healthier products, which have a high nutritional value and are also tasty."

Vertical farming

The answer to these challenges can take various forms. An interesting development is vertical farming," says Van Bodegom, "a completely closed cultivation system under artificial light, with reuse of water and fertilizers, and without or with very little use of pesticides. Productivity is very high because you can grow in several layers and harvest several times a year. The question is how to properly fit such closed farms into the region."

Another possibility is the open sustainable greenhouse, optimally integrated into the ecological and social environment. "The biological control in the greenhouse is supported by the functional biodiversity outside the greenhouse. Water consumption is coordinated with the environment, for example by capturing peak discharges to be used as irrigation water later. Solar panels on the greenhouse provide electricity to the surrounding area and excess heat is used for homes and buildings in the area."

'The combination of students from different schools that allow for integrating more practical and more conceptual knowledge is more likely to lead to practical solutions that are also sustainable in the long term.'

Network

The activities of the Centre for Sustainability are not limited to philosophizing about the future of greenhouse farming. The Centre is part of a number of networks - or rather, a large network with a number of nodes. One of those nodes is ACCEZ, an acronym that stands for the program 'Accelerating Circular Economy Zuid-Holland'. This partnership of the province of South Holland, the LDE Alliance, Wageningen University & Research and the employers' association VNO-NCW focuses on developing knowledge as the basis for policy to accelerate the circular economy in South Holland.

Another hub is the World Horticultural Centre (WHC) in Naaldwijk, an important meeting point for the business community and as such a source of research and educational questions. Van Bodegom: "Together with InHolland University of Applied Sciences and the 'green' Lentiz secondary vocational education (MBO), we have started a learning community. It connects students to companies to help them to solve problems they encounter. The combination of students from different schools that allow for integrating more practical and more conceptual knowledge is more likely to lead to practical solutions that are also sustainable in the long term."

Down to earth

That combination of conceptual and practical thinking is illustrative of the role the Centre for Sustainability wants to play. Van Bodegom: "On the one hand, we want to contribute to the development of an integral vision on the future of the entire chain, from supplier to consumer. On the other hand, we try to be down to earth, to provide concrete answers to the questions that parties in the supply chain are struggling with."

A major advantage here is that the expertises of Leiden, Delft and Erasmus are well aligned. Van Bodegom: "In Leiden we emphasize the environmental and biodiversity impact of the entire chain. In Delft the emphasis is on the 'translation' of that systems approach into technical systems, while Erasmus concentrates mainly on the business perspectives. In this way, we can make a good contribution to a resilient greenhouse horticulture sector in South Holland that is prepared for an uncertain future."