There is an urgent need to develop new methods for sustainable food production. This includes a greater emphasis on urban agriculture such as vertical farming which, properly designed and planned, could provide the sustainable means to improve food supply we need. Ideally, urban agriculture fits neatly alongside or within existing buildings in a self-contained and sustainable manner without competing for resources. Such urban plots can be at ground level or on rooftops. They can use greenhouses in order to take advantage of the sun’s energy, or grow indoors with the help of artificial lights.
Vertical Farming is promising because it requires no soil, and can save space and energy – and improve crop yield. It takes advantage of the vertical space of city buildings rather than turning over wide expanses of land to agriculture and uses advanced greenhouse technology: hydroponics or aeroponics, and environmental controls that regulate temperature, humidity and light to produce vegetables, fruits and other crops year-round.
In large cities such as New York, Chicago, Tokyo and Singapore, these ideas are taking root. Singapore has taken local urban farming to a high level – Skygreens has built the world’s first commercial vertical farm in large three-storey greenhouses, providing a sustainable source of fresh vegetables.
Vertical farming’s biggest limitation is energy consumption. Considerable energy is required to power a closed, indoor greenhouse facility’s artificial lighting, heating and cooling, and hydroponic or aeroponic growing systems. The amount of energy required per unit of product is an important factor for ensuring not only that the farm is sustainable, but that it is economically viable. Recently, more and more studies have focused on pairing solar panels and wind turbines with greenhouses to provide self-generated renewable electricity on-site.
But the single technology that will be key to making vertical farms possible is lighting. New LED light technology is the key that makes it possible to build vertically integrated farms. This kind of artificial light has an extremely high photoelectric conversion efficiency, consuming only one eighth the power of incandescent lamp, half of the power of fluorescent lamp, and using a lower supply voltage (6-24V) that makes it safer to work with and reduces transmission losses.
LED lights can be tuned to emit only a narrow wavelength of light, they can be combined to create perfect lighting that provide light on the ideal spectrum for a plant’s growth. Evidence is emerging that specific wavelengths of light have distinct effects on crop yield, quality, and even pest and disease resistance.
There is potential for these multifunctional techno-greenhouses built around LED grow lights to increase the quality of the food we eat and the amount that we can grow with the same land and resources: the very 21st-century problems we now face – and through technology are getting closer to solving.
source: livescience.com By Chungui Lu