In the 21st century, an unfortunate combination of increasing populations and dwindling resources means that we are experimenting more than ever with how to produce our food. Modern farming practices tend to be resource-intensive, requiring inputs such as chemical fertilisers and pesticides, huge swathes of land and fossil-fuel dependent techniques.
Another finite yet crucial resource that modern farming seems to be depleting is soil. There is obviously nothing new about farming with soil, but as the world’s soils are becoming increasingly degraded (about 5-7 million hectares of soil a year, according to the FAO) farmers are turning to new approaches which use less, or no, soil.
One of these ‘soil-less’ methods is hydroponic farming. The word “hydroponic” comes from the Greek words hydro (“water”) and ponos (“labor”). In hydroponics, rather than planting foods in the ground, the plants’ roots are kept in a nutritious solution. Nutrients that soil would be able to produce organically, such as calcium and magnesium, are added to the solution according to what the plant needs most. The plants are generally grown indoors, using artificial light, and stacked vertically on shelves.
The benefits of going soil-less
Hydroponics comes with its benefits. Avoiding use of soil means it also eliminates the risk of causing soil erosion. Since it is well adapted to vertical farming, it also means that it is likely to take up less space than conventional farming, and therefore use up less land. The few hydroponic systems that I have come across also invariably make use of disused buildings in urban centres, making use of infrastructure that would otherwise be wasted. Other benefits have been cited as being its efficient use of water, less (or no) weeds, lower risk of pests and diseases, faster growing times and better control over the growing environment.
Since then, farming has also seen the arrival of aeroponics (which uses the same concept but roots are suspended in the air and surrounded by a nutrient-dense mist). Another variety has been aquaponics, where aquaculture is combined with hydrponics in a symbiotic environment (each party feeds on the others’ waste). This system more closely mimics natural systems,
Taking the field out of farming
Permaculture approached to sustainable food systems tend to place soil at the heart of the matter, and advocate that in order to create the most nutritious food, you must ‘feed the soil, not the plant’. New techniques such as hydroponics effectively cutting out the middle man and feeding the plant directly, taking the ‘field’ out of farming. Whilst such soil-less systems may afford the farmer more control over the growing environment, they are also more restricting. Temperature needs to be maintained below 75 degrees Fahrenheit, meaning that air conditioning is often needed, making it instantly more energy intensive, especially when considering the energy required for artificial lighting.
There have been many arguments over whether these new soil-less techniques of farming can be deemed ‘organic’. The general premise of ‘organic’ has, until recently, meant that food was grown in biologically active, fertile soil. This has meaning for more than just the quality of our food, but also huge benefits for the soil’s system as a whole.
A systems approach to sustainable food cultivation is concerned with the soil system as a whole, on which we all depend regardless of how much food we can grow using hydroponics. By prioritising soil health, we can ensure that soil is healthy enough to perform its many other functions beyond food production, such as supporting tree and vegetation growth, not only us but life itself. Soil itself contains almost one third of the earth’s organic life, it is the largest store of carbon and plays the important role of filtering and cleaning water in the hydrological cycle.
Are soil-less practices avoiding our responsibility of protecting the earth’s soils? Whilst we may continue to produce food, we may still be causing damage to the world’s precious soil reserves through other pollution, agriculture for biofuel and general continuation of our many other unsustainable behaviours.
Soil in a sustainable food future
Ultimately, as I often profess, a mix of all approaches is likely to be the healthiest and most sustainable option. However, it is important that we remember to take a step back and consider how it may be designed, built and operated.
The goal of any efforts towards a sustainable food system should be to grow the most nutritious food possible with the least negative and environmental and social impact. To be truly sustainable, we need to take a systems approach. What resources does the hydroponic and similar systems use? How are they produced and are they finite? What are the social implications? Is it available to everyone or does it require extortionate capital investment? I feel that there may exist an element of risk that efforts to create more from less may steer too close to the factory model that has been so damaging to the global food system. However, as long as it is supported as a supplement to, not an alternative to, healthy and sustainable soil farming, techniques such as hydroponics can offer an exciting addition to a sustainable food future.
Technological developments which attempt to make this a little more slick, faster, more streamlined, may be very impressive and have many benefits, I am inclined to say that Nature knows best. After its millennia of trial and error and evolution, I think it is safe to say that Nature’s design is as better than anything we will ever be able to come up with. Soil and plant life hold a magnificent symbiotic relationship- nothing is wasted.