How can we produce enough food to sustain a growing population? Growing plants without soil could be the answer. As the world population approaches 7.5 billion, and world prosperity and the desire for more resource-intensive food also increase sharply, it is clear that agriculture needs to be more productive.
One way to meet future food needs could be hydroponics: to grow plants without soil, instead of using a nutrient-rich solution to supply water and minerals to their roots. It is already being used to increase agricultural production and grow plants in habitats that would not normally sustain them.
Even though it sounds like something out of science fiction, it's nothing new. The Aztecs built floating farms around the island city of Tenochtitlan, and explorer Marco Polo wrote about seeing floating gardens during his travels through 13th century China. By the 1930s, Pan American Airways had established a hydroponic farm on a remote Pacific island to allow its flights to be filled with food en route to Asia.
Today, farmers are slowly increasing their use of hydroponics, and researchers are watching more closely how they could solve future food problems. In the future, some of its applications may be out of this world.
How Hydroponics works?
In conventional agriculture, the soil supports a plant's roots - helping it to stay upright - and provides the nutrients it needs for growth. In hydroponics, plants are artificially supported and a solution of ionic compounds provides nutrients.
The thought behind this is simple. Plant growth is often limited by environmental factors. By applying a nutrient solution directly to the roots of a plant in a controlled environment, the farmer can ensure that the plant always has an optimal supply of water and nutrients. This nutritional efficiency makes the plant more productive.
The solution can be provided in different ways. A plant can be:
- placed in an inert substance (such as volcanic glass perlite or rock wool) and its roots periodically flooded with solution
- placed in an inert substance and rained by a solution dripper
- suspended with its roots in the air, then sprayed with fog of solution
- placed on a slightly sloping film that allows the solution to flow on its roots
All these systems are mechanized in one way or another, usually using a pump or vacuum cleaner, to deliver the solution from a separate store. The solution is also generally aerated to ensure that the roots receive enough oxygen. The absorption of minerals requires energy and is powered by respiration.
is Hydroponic Hard?
The operation and maintenance of a hydroponic system can be complex. Plants require more than a dozen essential nutrients, and the optimum amount of each varies according to the species, the stage of growth and local conditions, such as the hardness of the water.
In addition, some nutrients are absorbed faster than others, which can cause an accumulation of positive or negative ions in the solution, which affects the pH. This can hinder the absorption of other nutrients, partly because their absorption depends on the pH, but also because the excess amounts will prevent the absorption of others. Too much ammonia, for example, decreases the absorption of calcium. Too much calcium prevents the absorption of magnesium.
In addition to this, some compounds react with each other to form substances that are more difficult to absorb, so they must be provided separately. Hydroponic farmers should have a firm understanding of how plants and nutrients interact, and should monitor their solutions closely and respond to any change in concentration. Your other option is to buy expensive automated systems to do this for them.
Farmers must also protect their nutrient solutions so that they are not contaminated with unwanted substances. Enclosing hydroponic systems inside buildings or greenhouses is a common way of doing this. It also allows them to control and optimize other environmental influences on the growth of plants, such as temperature, light and CO2, to further increase yields.
When people talk about hydroponics today, at least in agriculture, they usually mean not only growth without a single partner, but the collective control of all these factors. However, this combined practice is more precisely known as controlled environment agriculture.
Hydroponic crops
Theoretically, hydroponics can be used for any crop. However, the technique is mainly used with plants that grow effectively under hydroponic conditions, such as salad leaves, cucumbers, peppers and herbs. Most often, it is used to grow tomatoes.
Farmers tend to use hydroponics with varieties of tomatoes that have particular characteristics, such as carrying larger fruits and growing indeterminately (which means they grow continuously, producing fruit repeatedly along the length of the crop). their stem).
Disease resistant varieties are also popular because they allow plants to live longer and produce more.
Urban agriculture
The vast majority of plants are still grown using soil, but hydroponics is on the rise. In 2013, Thanet Earth, the largest greenhouse complex in the United Kingdom, based in Kent, used controlled environment agriculture to produce around 225 million tomatoes, 16 million peppers and 13 million cucumbers, which is equivalent respectively to 12, 11 and 8 percent of all the annual production of Great Britain. of these crops. Currently operates four greenhouses, and has plans to build another three.
Worldwide, it was estimated that the hydroponic agricultural industry had a value of $ 21.4 billion in 2015, and its value is expected to grow by 7 percent per year. Slowly but constantly, agriculture seems to be changing.
But equally, there are major global changes on the horizon, and these could greatly accelerate the use of controlled environment agriculture. By 2050, 3 billion more people may be living on Earth, with more than 80 percent of the world's population living in urban centers. We are already using the vast majority of suitable land for cultivation, so it is necessary to find new areas of cultivation, especially in arid regions.
A highly commented solution is vertical urban agriculture: the creation of hydroponic farms stacked inside buildings, including tall skyscrapers. This would solve the problem of running out of available agricultural land, and would also place farms at the center where crops are needed: our most populated cities of the future. Vertical farms are already being built in Michigan and Singapore, and even in disused bomb shelters in south London.
