05-10-2020   |    iFarm

Since Aristotle, people believed that plants exclusively feed on organic matter. Only in the 18th century did these ideas begin to be questioned. Scientists discovered that in fact plants’ primary source of nutrition is inorganic in nature. Similar myths exist today. One of them is that soilless cultivation is an artificial process, during which tasteless vegetables, berries and greens grow rapidly almost on "steroids". We compared hydroponics — one of the most common and sustainable soilless crop cultivation technologies, with traditional farming to identify their key differences and similarities.

A bit of history

The concept of "hydroponics" was introduced in the 1930s by the American biologist William Gericke.

During the Second World War, the first hydroponic plantations were launched using this technology. Since the 1970s, hydroponic systems of various modifications have begun to appear in different parts of the world. Today NASA is working on an inflatable expandable greenhouse where hydroponics will be used. It is planned to be installed on Mars so that the first settlers can provide themselves with fresh vegetables, berries and herbs like on the Earth.

Hydroponics combines several methods of plant cultivation in artificial environments: wick and drip irrigation systems, flooding irrigation, nutrient layer method, etc. On iFarm vertical farms, we use the flow hydroponics method: seeds are sown in one of the types of substrate (peat or mineral wool), and nutrient solution is served into the pots from below.

A huge advantage of hydroponics is its controllability. The technology makes it possible to create ideal conditions for plants in terms of nutrition, lighting, temperature, and environment. In an optimal microclimate, they reveal their maximum potential, useful properties, have a prominent taste and aroma.

Nutrient intake

All elements of root nutrition are absorbed by plants either from the soil or a mixture of water-soluble fertilizers only in the form of ions.

Growing in soil

The content and availability of macro and microelements (nitrogen, potassium, phosphorus, magnesium, iron, etc.) in the soil is influenced by the temperature of air and soil, the amount of solar energy and moisture, the pH of the environment. Natural conditions are very unstable: air temperature and pressure fluctuate during the day, the sun is often covered with clouds, there may or may not be any rain for several days. All this affects the availability of nutrients for plants, causing a deficit of one or more of them, which in turn reduces yields and product quality. To accelerate plant growth and ensure yields, people began to use mineral or organic fertilizers.

Hydroponics
The microclimate inside a vertical farm is stable and the plants get nutrition in the amount they require. "We do not accelerate the growth of plants, but create conditions in which they can fully develop, without experiencing a lack or excess of nutrients and stress from changes in the environment. All this allows you to get tastier and earlier harvests," said Natalia Smirnova, a plant nutrition specialist at iFarm. iFarm labs select balanced nutrition for all crops grown on vertical farms. In fact, macro- and microelements are the same, but the delivery methods to the root systems may differ.

iFarm agrochemists select a balanced diet not only for each crop, but also for a specific phase of its development (the amount and ratio of consumed macro- and microelements depends on it). They can adjust the supply of nutrients to plants to get fruits not only with specified taste characteristics but also with a specific concentration of iron, silicon, vitamins, carotene, and other components important for human health.

The quality of vegetables, berries, or herbs does not depend on the method of their cultivation, but on the conditions the plants grew in, regardless of the environment being natural or artificial. Products that taste like "plastic" are often obtained using a large number of fertilizers, growth stimulants and pesticides, helping fruits to gain weight faster and increasing their shelf life. They are usually harvested without being given time for natural ripening or accumulation of nutrients (although two or three times per season).

Natalia Smirnova

Candidate of Biological Sciences,
iFarm plant nutrition specialist

Protecting from pests and diseases

In the closed ecosystems of vertical farms pests cannot infect the plantings (there is no need to fight them, that is why production is pesticide-free unlike traditional field farming or greenhouses). You can lose crops only due to disturbances in plant nutrition.

Growing in soil

10 billion microorganisms live in 1 g of black soil. Some of them are pathogens (fungi, viruses, and bacteria) that cause various diseases in plants. In order to protect crops and keep harvests, agricultural producers are forced to use chemical agents (pesticides: herbicides, fungicides, insecticides) in the fields while growing. In addition, ripe fruits are also processed for safety during transportation. Pesticides remain on products even after washing in water and, once they enter the human body, can cause diseases of the gastrointestinal tract, oncology, reproductive and endocrine disorders, etc.

Hydroponics

Vertical farms using iFarm technologies have a closed microclimate. An energy-efficient air purification and disinfection system ensures complete absence of outside air, any pollution, pests or diseases. The substrate that holds the roots of plants is purchased from leading international manufacturers. iFarm agronomists always check suppliers' quality certificates and test substrates in laboratories. For the nutrient solutions, we use treated water, purified in a special system that eliminates any impurities letting in only oxygen and water molecules through a membrane. There is simply no need to use pesticides.

Soilless cultivation also allows to carry out an early analysis of the root systems, giving a chance to evaluate every single plant’s condition. On vertical farms, root access is always open.

Water consumption

Vertical farms use 90% less water than greenhouses. Special engineering solutions can help to further improve this number to save even more water, allowing the plants to receive precisely required amount of moisture.

Growing in soil
Producers annually calculate the irrigation norm rate — the amount of water plants require to fully grow. It depends on the climate, soil properties, crop characteristics, cultivation technology. However, it is difficult to calculate accurately due to the unreliability of weather forecasts. As a result, plants may receive too little or too much water. Failure to comply with irrigation norms washes away the upper layers of the soil: irrigation erosion annually carries away 100−150 t/ha of soil, 0.8−1 t of humus, 100−120 kg of nitrogen, and 110−165 kg of phosphorus. On such soils, crops grow unevenly, and yields decrease.

Hydroponics
Thanks to the automated microclimate, the amount of water required by plants to fully develop is determined with an accuracy of a milliliter. iFarm engineers have also developed a dehumidification system to collect moisture evaporated by plants, filter, decontaminate and reuse it to water crops. This will help save even more water, which is incredibly useful in regions where water resources are limited (when grown in soil, moisture released by plants simply evaporates).

www.nutrienhorticulture.com.au

The advantages of hydroponics (climate controllability, pesticide-free production, preservation of the environment) stimulate the growth of the global vertical farming market. According to Research and Markets, in 2017 it was about $ 2.3 billion, and by 2023 it will grow to almost $ 7.5 billion, adding more than 20% annually.

Source and Photo Courtesy of iFarm