Norwegian researchers are testing a new greenhouse cultivation method which emits very little gas. Norwegian, and global food production, is, after all, a major source of emissions. That's mainly because growers use artificial fertilizers and non-recyclable raw materials.
Ketil Stoknes very recently received his doctorate from Oslo University's Life Sciences Institute. He names some examples, saying, "Today's industrial food production is mostly a linear system. That's an inefficient process that produces a lot of waste."
Zero-emission greenhouse horticulture
Stoknes has been developing and testing a specific farming method. It can significantly reduce the number of raw materials used and the amount of emission in greenhouse horticulture. "My primary goal is to transform food wastage into new foods."
"The cycle is as closed as possible. We tested the method in a pilot greenhouse in Tønsberg (on the Oslo fjord). There, we can now convert food and vegetable waste into other things. These include bio gasses, edible mushrooms and vegetables, and potting soil."
Closed, controlled system
This biogas system produces pure biomethane and organic fertilizer. These can be used, respectively, by busses and trucks, and grain farmers. The greenhouse receives CO2 that's purified from the raw biogas and the same organic manure.
"This organic fertilizer can be used to grow mushrooms and tomatoes," says Stoknes. "Afterward, the medium is pasteurized and can be sold as, for example, potting soil. But, most importantly, everything happens in a closed, controlled environment. It's a greener alternative than traditional fruit, vegetable, and mushroom farming. In this trial run, we're using no fertilizer, only organic waste."
Inspired by Mars technology
Ketil was inspired by NASA's plans to construct closed system colonies on Mars. "We have the same experience as the Mars scientists. It's vital to have vast biological diversity in a closed system like that. Not only plants but, for instance, also micro-organisms. These are found in cultivation mediums and the earthworms you find in compost. So, everything balances itself out. Organisms can make corrections if the system gets out of whack."
This new cultivation method is called digeponics (from Digester hydroponics). It's a further development of the aquaponics growers currently use in greenhouses. "The new thing is that we've found a sustainable farming method that uses ecosystems and waste. That's resulted in a partnership between the waste, scientific, and greenhouse horticultural sectors."
These new greenhouses still need some power. That's used to control the temperature. Their energy consumption is, however, greatly reduced. The walls have two layers of plastic. You fill the space in between with soapy water. That prevents air movement, so creating extra isolation. The pilot greenhouse has produced its first crop of emission-free tomatoes. These are being sold in Meny supermarkets in Norway as 'Climate tomatoes'.
Stoknes stresses that this new method doesn't suit all kinds of foodstuffs. For now, farmers will still have to cultivate grains and potatoes 'normally' in soil. But, this new method offers cities the chance to become self-sufficient. They can have greenhouses full of fruit, vegetables, and mushrooms.
"In Bergen, for example, they can't easily use food-produced organic fertilizers. Farmers in that region have more than enough manure from livestock production. So, they could build greenhouses that use these new cultivation methods. Then, that city would be well on its way to becoming self-sufficient," he concludes.
Source (incl. explanation in the video): forskning.no