Viewpoints

Can greenhouse horticulture help climate smart agriculture?

Dutch Greenhouse. Image via Flickr: -JvL-
Dutch Greenhouse. Image via Flickr: -JvL-

Greenhouse horticulture plays a big part in keeping a consistent supply of food on our tables.

But as mitigation of and adaptation to climate change in the agricultural sector becomes increasingly important, so too, does innovation in reducing greenhouse horticulture emissions.

Climate Smart Agriculture Booster, a Climate-KIC supported collaboration between organisations including Potsdam, CDP and Wageningen University has the aim of advancing the technologies and policies to foster “climate smart” agriculture to mitigate, adapt and sustainably produce.

Earlier in the summer, it brought together group of California and Netherlands based organisations together from across the sector to host a series of webinars to discuss development in the sector.

In this episode, greenhouse horticulture innovators discuss up-to-minute examples of leading technologies including hydroponics, energy-efficient LED lightening, resource use efficiency, automation and regulation, how fast innovation is taking place, and the challenges faced.

What technology is there for climate smart agriculture?

Dr Heiner Lieth, Professor of Environmental Horticulture, UC Davis, gave examples of a hybrid greenhouse/solar photovoltaic system, that give plants in nurseries some shade from hot conditions, and allow excess energy to be sold on for a profit.

A second he gave, was a prototype indoor plant factory, where LED lighting is making it possible to grow many more crops indoors without changes in sunlight or climate, without pesticides, and with very high water-use efficiency.

He also outlined how there were lots of learnings in water and fertiliser use in greenhouse horticulture, that could be transferred to field production, noting an example of soil-less outdoor strawberry production.

How can we reduce the use of fertiliser, water?

Dr. Silke Hemming, Wageningen University, responsible for research into greenhouse technology explained how the country is making progress towards independence from chemical fertilisers, by introducing insects to eat pests rather than pesticides.

She added how a closed greenhouse which recaptures the water lost through transpiration of the crop, might yield ten times more produce per cubic metre of water than a Mediterranean field — a concept useful for production in drier places like California.

What about energy reduction?

Leo Oprel, Dutch Ministry of Economic Affairs, spoke of the success of the ‘Kas Als Energiebron’ plan to make energy supply to greenhouse horticulture sustainable. The Dutch have already met goals for 2020 energy reduction, and have an ultimate goal of zero net emissions by 2050.

One example of how they have achieved this is through close work with industry stakeholders, and paying a subsidy to encourage innovators, with first adopters to new energy technology receiving 40 per cent of the cost.

What’s in it for the industry?

Joep van den Bosch, Chief Innovation Officer, Ridder-Hortimax Group, which designs, builds, and maintains greenhouse technology solutions says the sector wants to save money.

Technology can minimise water use; re-circulation can reduce the need for fertiliser by 30 to 40 per cent — enough for a grower to get their investment in the re-circulation technology back, a return on investment that increases the production per square metre.

As well as saving money by reducing water and fertiliser, local production means crops can be picked ripe, and stay fresh on the supermarket shelf for longer, meaning customers come back for more. An added benefit of local production means reduced emissions from transport.

What about vertical farming?

Van den Bosch thinks the technology isn’t quite there yet. The cost is two or three times higher than conventional greenhouses, natural light is cheaper than using fossil fuel powered LEDs, and the cost of cooling in a hot place is prohibitive, and unless you’re using robotics, it’s much more efficient to harvest in 2D. However, In 10 to 20 years he envisages companies might be selling ‘recipes’ that would enable indoor farms to be run by people with little or no growing knowledge.

How is the industry adopting these ideas?

David Bell, Chief Marketing Officer, Houwelling’s Group, explained how year-round growth by being based in sunny California leads to lower emissions than growing elsewhere.

At the group’s site in California, its closed loop hydroponic irrigation and re-circulation enables them to reduce water use to one-sixth of that of a field and allows them to measure and reduce fertiliser. The company chose to use three gas engines to make the products for the greenhouse.

Carbon dioxide feeds the plants, replacing the use of liquid carbon dioxide, and electricity not used for heat or operating the greenhouse sold to the the grid. Condensed water is also produced, providing some 14,000 gallons of water each day for the greenhouse. Solar panels offset some of the energy use of the cooling fans and carbon dioxide circulation system.

At its newer site in Utah, the company has gone one step further, rather than burning its own gas, it has situated its greenhouse next to an existing gas power station. Similarly, it uses carbon dioxide flue gases from a power plant for energy storage and carbon dioxide fertilisation.

However, Bell believes the US industry is not following its lead as regulation isn’t up to speed (the Utah greenhouse isn’t allowed to capture rainfall from the roof). “It’s been a difficult and expensive execution for the company.”

Mitigation, adaptation and sustainable production in greenhouse horticulture

Lowering of agricultural emissions has been achieved in The Netherlands and California through the reduction of transport by local growth, reduction of the use of fertiliser, the circulation of carbon dioxide (even using carbon dioxide from industrial plants for better plant growth), and through finding alternatives to energy from fossil fuel.

With climate adaptation, re-use of water can really make a dramatic impact, especially in water scarce place like California, and indoor farming has great potential to avoid crops being damaged by extremes of weather.


Listen to the full webinar, ‘Business Opportunities of Greenhouse Horticulture as a Comprehensive Climate Smart Agriculture Solution’, here

To see an overview of the entire webinar series, click here.

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