Academics at the University of Nottingham have patented a new concept that would see food production in deep farms in cities. The ideas are being promoted by University of Nottingham academics Professor Saffa Riffat, Fellow of the European Academy of Sciences and President of the World Society of Sustainable Technologies, and Professor Yijun Yuan, Marie Curie Research Fellow.

Deep farming technology would allow crop production all year-round. Up to 10 crop cycles per year could be achieved compared to 1-2 cycles for conventional agriculture. Put another way, 1 indoor acre is equivalent to 4-6 outdoor acres or more, depending on the crop.

As Deep Farms could be located close to urban centres, CO2 emission due to transportation of crops would be reduced. This is particularly important as the proportion of people living in cities continues to rise. Over the last 20 years, the percentage of people who live in cities globally has increased from 20% to nearly 50%.

Cost-effective deep shafts for crop planting would be constructed using new drilling techniques. Existing coal mine shafts, mines and tunnels, many of which are now abandoned could also be used for crop production.

A variety of crops could be grown in the Deep Farms using hydroponic planters (plant roots fed with nutrient-rich water) or aeroponics (growing plants in an air or mist environment). LED units would enable photosynthesis in the absence of sunlight. Groundwater could be used directly or water could be condensed from ambient air in hot/humid desert climates. A major benefit of this approach is that crop production is largely unaffected by climatic or seasonal factors - one of the greatest limitations of conventional farming methods.

New vertical shafts could be created for Deep Farms and also redundant coal mine shafts could be used for crop production. In the UK, for example, there are over 150,000 redundant coal mine shafts.

Carbon dioxide is required for plant photosynthesis and Deep Farms are well suited for carbon capture from ambient air. The CO2 could be released to achieve the concentration levels required by plants. 
Use of carbon capture systems has the added benefit of reducing CO2 concentration in the environment, as additional carbon is adsorbed in materials in the ground space. Advanced control systems including sensors and remote controls could be used to monitor crop production. Automated systems such as robots could be used for crop planting and harvesting. Electricity generated from renewable sources and off-peak power could be used to power the LED lighting for plant photosynthesis.

It is estimated that a small Deep Farm can produce 80 tonnes of food per annum. Some of the crops can be ready for harvesting within 2-3 weeks. The amount of energy it would require is equivalent to that consumed by 3 UK homes.

Deep Farms could be installed at various locations to create a ‘Deep Farming City’. This would facilitate the supply of a wide range of fresh crops to the local population.

For more information:
University of Nottingham
Professor Saffa Riffat 
+44 115 748 4479
www.nottingham.ac.uk