In my first post I stated that
without soil we would simply starve… well this may not be strictly true. Plants
require water, light, aeration, nutrients and support; they do not explicitly
require soil… this is just a medium that happens to bring all of these factors
together.
Hydroponics:
Plants can be grown in
nutrient-rich water, held in place by manmade support structures. Modern
hydroponic systems were developed in the 1930s but evidence suggests that the
Hanging Gardens of Babylon, which date back to ~600 B.C., depended on
hydroponic culture. Clearly, it’s not a new concept. Plants grown
hydroponically absorb nutrients more efficiently, thus increasing yield.
Aeroponics:
In the 1980s, scientists took
this one step further and began growing plants in air! They found that 'misting' water vapour and nutrients to the plant made it easier to aerate the root structure.
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Fig. 1 Diagram outlining typical ‘aeroponic’ setup (Source: www.soilless.org)
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Vertical farms:
If we used these approaches to
grow food indoors, stacked up in city
skyscrapers, we could eliminate the need for agricultural expansion and could protect ourselves against the limitations of agricultural intensification (soil
degradation and climate change). We could also prevent fertilizer runoff, use
less water and reduce the need for transport from distant rural farms, which
adds cost, consumes fossil fuels and causes significant spoilage. In 1999, Dickson Despommier
proposed a ‘vertical farm’ design, which he claimed could produce 2,400 acres
worth of food in one 30-story high, five acre plot, using no soil and running
entirely off renewable energy. He argued that although upfront costs may be high,
once operational these farms would be able to produce food that is cheaper than
current supermarket prices. Nevertheless, vertical farms are unlikely to be
able to supply our entire global food demand alone. Therefore, in my opinion soil is
still essential.
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Fig. 2 The front cover of the most recent edition of Dickson Despommier’s
book called ‘The Vertical Farm’. (Source: Amazon)
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