Today, food production has a huge climate and environmental footprint. This also applies for vegetable production, where growers need to make sure that their plants have sufficient fertilizer up to harvest so that cabbage and other crops are attractive and appetizing when they land in the shops.

"There’s a great risk of nitrogen leaching when you grow on open fields. For this reason, we’re interested in being able to supply more knowledge to growers about how they can produce more vegetables without unnecessarily burdening the environment," says Associate Professor Hanne Lakkenborg Kristensen, a biologist who is the head of the Plants, Food and Sustainability research group at the Department of Food Science at Aarhus University (AU).

Her group is researching into environment, climate and biodiversity aspects in cultivating open-grown vegetables. The group is currently examining the benefits of joint-crop cultivation for certain crops. Hanne Lakkenborg Kristensen expects many synergy effects from growing alternating rows of beetroot and white cabbage. For example, white cabbage roots can reach deep into the ground and pick up nutrients under the root zone of beetroot. Furthermore, beetroot and white cabbage may together constitute a good environment for beneficial insects.

New types of fertiliser are another focus of the research group. Today, manure is an important source of good cabbage and root-vegetable yields, including in organic production, but research results from the Department of Food Science have demonstrated that clover and other legumes, which the growers themselves can cultivate, can also be good fertilizer. This means it may be possible for growers to stop using animal nutrients in production.

Green manure and fixed tracks

The Aarstiderne food company is one of the partners from the business community which have been involved in several research projects at the Department of Food Science.

According to Aarstiderne’s head of agriculture and environment, Svend Daverkosen, this collaboration is absolutely essential for the company:

"We live on innovation. So we must always be at the forefront with new types of crops and new cultivation systems. When we collaborate with Aarhus University, we gain knowledge about cultivation, which we try out on our experimental fields at our headquarters in Barritskov, and then take further to our many suppliers," he says.

Svend Daverkosen recognizes that, as a project participant, he has to offer time and often patience to the research projects. Especially when the research team has to take hundreds of soil samples and a process has to be repeated many times. “But this is all forgotten when results fall into place, because they have great value for our business,” says Svend Daverkosen, and he gives an example:

"Since 2014, we've only been using green fertilizers on our experimental field. This is the result of a research project we were part of, in which we tried out the method in practice and developed machinery to handle the new way of fertilizing. Now we’re self-sufficient in fertilizer."

One of the most recent research projects completed by Hanne Lakkenborg Kristensen's Plants, Food and Sustainability group has demonstrated that the tracks farmers’ tractors leave on fields have an impact on soil quality and yields:

"We’ve been able to demonstrate that, if the growers use a fixed track in organic vegetable production, the soil between the tracks, i.e. where the crops are growing, becomes more fertile. We could also see that it stimulated root growth and the nitrogen cycle was better, benefiting the sustainability of the ecosystem. I’m proud of this, not least because it’s a relatively easy cultivation method for growers to implement," explains the research director. 

The research is being supported by, among others:
• The green development programme (Grønt Udviklings- og Demonstrationsprogram (GUDP)) )) under the Ministry of Environment and Food of Denmark,
• Coordination of European Transnational Research in Organic Food and Farming Systems (CORE organic)
• Innovation Fund Denmark

Greenhouses cannot replace fields

Now and then, Hanne Lakkenborg Kristensen is asked:

"Can’t the vegetable production of the future be sheltered from climate change in greenhouses?”

The associate professor doesn’t think so:

"We need different cultivation methods as we eat more and more vegetables, but I find it hard to imagine that we'll allow greenhouses to dominate the Danish landscape. Moreover, a large number of our vegetable crops, such as root vegetables and cabbage, thrive best in the open. Therefore, I expect that the growth in green food production in Denmark will primarily take place in open fields," explains Hanne Lakkenborg Kristensen.

If her prediction is correct, that our eating habits will become ever-more green at an unprecedented pace, sustainable food production will already be very visible from our train or car window in just a few years.

"It's not my place to decide how much focus there should be on the green agenda, but there’s a lot going on right now. If this continues, within five to ten years, we’ll see fields with a high diversity of sustainably cultivated vegetables that can make delicious meals," says Hanne Lakkenborg Kristensen.  

Contact

Associate Professor Hanne Lakkenborg Kristensen, research director
Department of Food Science - Plants, Food and Sustainability
Aarhus University

Email: hanne.kristensen@food.au.dk
Mobile: +45 2069 8054