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Indian Farmer 6(4): 286-292; April-2019 Kumari and Kumar
286 | P a g e
Aeroponics: A Review on Modern
Agriculture Technology
Reena Kumari1 and Ramesh Kumar2
1Senior Research Fellow, Department of Vegetable Science, Dr YS Parmar University of
Horticulture and Forestry, Nauni, Solan (HP), 173230
2Principal Scientist, Department of Vegetable Science, Dr YS Parmar University of Horticulture and
Forestry, Nauni, Solan (HP), 173230
*Corresponding Author: reena.sarma92@gmail.com
Abstract
Aeroponics is a promising soilless farming method for solving future food crisis and is relatively a
new way of growing plants that is getting increasingly popular with many people because of the
speed, cost and novelty. Aeroponic farming is a form of hydroponic technique and a type of
vertical farming. The word aeroponic is derived from the Latin word ‘aero’ (air) and ‘ponic’
means labour (work). This farming system empowered the producer to precisely control root
zone nutrients, water regimes, and environmental conditions and have complete access to the
roots throughout the life of the crop. This aeroponic farming is superior in terms of excellent
aeration, water use efficiency, less time and space requirement, seasonal independence, disease
free plant propagation, and large scale plant production etc. than the conventional methods of
propagation. Aeroponic techniques have proven to be commercially successful for propagation,
seed germination, seed potato production, tomato production, leaf crops, and micro-greens.
Vegetable crops like potato, yams, tomato, lettuce and some of the leafy vegetables are being
commercially cultivated in aeroponic system. Aeroponics appeared to be a highly feasible method
for the production of both aerial parts and roots.
NEED OF AEROPONICS
The current world population of 7.2 billion is projected to increase by almost one billion
people within the next twelve years, reaching 8.1 billion in 2025 and 9.6 billion in 2050.
With the increasing population growth the demand for the more food and more land to
grow food is ever increasing. As the world population continues to grow, the rising
demand for agricultural production is significant. Prime agricultural land can be scarce
and expensive. Aeroponics is a technological leap forward from traditional hydroponics.
Aeroponics-farming are also needed due to the many drawbacks of the traditional field
farming system. Some of the drawbacks of the traditional farming system are 15 hours
to harvest the crops, long time to harvest hence being sold for more expensive prices to
earn back the time. Another factor is soil used in traditional system, decomposition of
organic materials takes up long time. There is a high risk of getting soil disease.
Pesticides are used, which is harmful for health. Whereas, in a developing country like
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India, it is very important to use resources like water, sunlight, soil and money very
efficiently.
HISTORY
Aeroponic research began in the 1920’s and progressed steadily as a soilless growing
method. In the early 1940s, the technology was largely used as a research tool rather
than an economically feasible method of crop production. W. Carter in 1942 was the
first researched air culture growing and described a method of using water vapor at the
plants roots to deliver nutrients to facilitate examination of roots. In 1944, L.J. Klotz was
the first to discover vapor misted citrus plants in a facilitated research of his studies of
diseases of citrus and avocado roots. In 1952, G.F. Trowel grew apple trees in a spray
culture. The first commercial aeroponics setup was the Genesis Rooting System,
commonly called the Genesis Machine, by GTi in 1983. The device was controlled by a
microchip and simply connected to an electrical outlet and a water faucet. During the
1990s, NASA carried out a series of tests in space and on earth growing biomass with no
soil and very little water and this method proved to be very productive. NASA research
has shown that aeroponically grown plants have an 80 per cent increase in dry weight
biomass (essential minerals) compared to hydroponically grown plants. Aeroponic
techniques have been given special attention from NASA since a mist is easier to handle
than a liquid in a zero-gravity environment.
INTRODUCTION
Aeroponics is an alternative for people with limited spaces to grow plants. An
aeroponic system is defined as an enclosed air and water/nutrient ecosystem that
fosters rapid plant growth with little water and direct sun and without soil or media. It
is an effective and efficient way of growing plants for it requires little water (requires 95
per cent less water than traditional farming methods) and needs minimal space than
even the most efficient system hydroponic system.
Plant grown in these aeroponic system also been shown to uptake more minerals and
vitamin, making the plants healthier and potentially more nutritious. The suspended
aeroponic plants receive 100 per cent of the available oxygen and carbon dioxide to the
roots zone, stems, and leaves, thus accelerating biomass growth and reducing rooting
times. The higher biomass yield of aerial parts from the aeroponic treatment indicated
that this production technique should not be limited to root crops, but should be
considered for other types of crops as well. Furthermore, using aeroponics, planting
densities can be increased since plant-to-plant competition for nutrients and water is
essentially eliminated. Any species of plants can be grown in a true aeroponic system
because the micro-environment of an aeroponic can be finely controlled.
Aeroponic systems for seed production have been established following increased
demand for more efficient high quality seed production methods. Aeroponic bio-
pharming is used to grow pharmaceutical medicine inside the plants. Using aeroponics
for cloning improves root growth, survival rate, growth rate and maturation time.
Studies have shown that, the mean tuber yield under aeroponics is better than when the
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same material is left to produce tuber under conventional means. Some researcher
reported that, the aeroponics system increased stomatal conductance of leaf,
intercellular CO2 concentration, net photosynthetic rate and photochemical efficiency of
leaf.
TYPES OF AEROPONICS:
a. Low-pressure Units: In most of the low-pressure aeroponic gardens, roots of the
plant are suspended above a reservoir of nutrient solution or a channel which is inside
and is connected to a reservoir. The nutrient solution is delivered by a low-pressure
pump through jets or by ultrasonic transducers, which drips or drains the nutrients
back into the reservoir. When plants grow to maturity, then the units suffer from dry
sections of the root systems and thus adequate nutrient uptake is avoided. These types
of units lack features to purify the nutrient solution, removal of debris and unwanted
pathogens because of cost. These units are usually suitable for bench top growing. And
it is also used for the demonstration of principles of aeroponics.
b. High-pressure Devices: In high-pressure aeroponic devices, mist is created
by high-pressure pump(s). And it is generally used in the cultivation of high value crops.
This method includes technologies for air and water purification, nutrient sterilization,
low-mass polymers and pressurized nutrient delivery systems.
c. Commercial System: The commercial system has high-pressure device
hardware and biological systems. An enhancement for extended plant life and crop
maturation is included in the biological systems matrix.
Working:
Aeroponic system is an endless process in a confined space and therefore it cuts
down agricultural labour. Aeroponics are based on the possibility of cultivating
vegetables whose roots are not inserted in a substratum (the case with hydroponics) or
soil, but in containers filled with flowing plant nutrition. The basic principle of
aeroponic growing is to grow plants suspended in a closed or semi-closed environment
by spraying the plant’s dangling roots and lower stem with an atomized or sprayed,
nutrient-rich water solution.
The set up for aeroponic includes a proper monitoring and control system for
water and nutrients distribution for utilizing the aeroponic cultivation at its best.A
distribution system of pipes, spray nozzles, a pump and timer distributes the spray from
a nutrient solution storage tank is required. It uses a small internal micro jet spray that
sprays the roots with fine, high pressure mist containing nutrient rich solutionsfrom the
nutrient reservoir as a fine mist in the rooting chamber.There is a programmable cyclic
timer which is used to trigger the high-pressure aeroponic pump to go on. Nutrients are
mixed in with water in a reservoir basin, this is than filtered and pumped into a
pressurized holding tank that is intermittently misted on to the root system.
Developed root hairs help in absorbing nutrients from the moisture. It is also
easier to administer all sorts of nutrients to the plant, via the root system.Since the
spray particles are small in size, there is negligible wastage of nutrient solution. And
with an ample amount of oxygen supply, root rot is completely avoided.
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The misting is usually done every few minutes around the hanged roots. The
system normally turned on for only a few seconds every 2-3 minutes. Because the roots
are exposed to the air, the roots will dry out rapidly if the misting cycles are interrupted.
A timer controls the nutrient pump much like other types of hydroponic systems, except
the aeroponics system needs a short cycle timer that runs the pump for a few seconds
every couple of minutes. However, the chamber must be lightless materials from
everywhere, so that the roots are in darkness functionally good also to inhibit algal
growth that impedes the growing plants and pollute the system.
The droplet size of a nutrient mist is a crucial element in aeroponics. An
oversized droplet may reduce the oxygen supply. An undersized droplet may stimulate
root hair growth which prevents lateral root growth which influences the efficiency of
an aeroponic system. The water droplets must be big enough to carry the nutrients to
the roots in sufficient quantity, but small enough to not immediately precipitateout of
the root mass. Unused solution drips downinto the baseof the unit is strained, filtered,
and pumped back into the reservoir. Aeroponics system is that of easy monitoring of
nutrients and pH. In aeroponics there is the minimal contact between the support
structure and plant, due to which the unconstrained growth of the plant is possible.
DIFFERENT COMPONENTS OF AEROPONICS:
1. Nutrients used in aeroponics: Mainly N-NH4 (0.54 g/L), N-NO3 (0.35 g/L), P(0.40
g/L), K (0.35 g/L), Ca (0.17 g/L), Mg(0.08 g/L), Na(0.04 g/L), Fe (0.09 g/L), Zn (0.03
g/L) and B(0.03g/L) are commercially being used in most of the crops.
2. Water used in aeroponics: Water to be used in aeroponics should have a low EC,
not exceeding one mS/cm. Water pH is also a useful indicator. Water sources with a
pH of over eight are questionable for aeroponics. It is useful to have a water
chemical analysis; even if EC and pH measures fall into acceptablelevels.The other
problem we may have to face is water biological contamination. Water from deep
wells isusually not contaminated. Water from superficial wells, especially near
urban areas, is likely to be contaminated with coli form bacteria, including
Pectobacterium. Water from suspicious sources shouldhave a microbiological
analysis. Special filters can minimize this risk. If available, water should be
filteredbefore going into the nutrient tank. Boiling is also another alternative if no
other is available.
3. The plant material used in aeroponics: Optimum plant material should be used
for aeroponics. In vitro plants are preferred because of sanitaryreasons. However,
they need to be handled with proper care by experienced technicians. These
plantsshould be the appropriate age and size and should go through a thorough
acclimatization periodbefore going into the greenhouse. Other plantmaterials, such
as rooted cuttings and tuber sprouts, should be clean and disease free. The presence
ofany kind of symptom should be sufficient reason to discard the whole batch of
plants. This should benoticeable when transplanting into the boxes. The
underground part of the tissue coming from thesand trays should be completely
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clean and sand free. Before placing into aeroponics, plants should be managed in a
clean greenhouse environment.
SOME OF THE KEY BENEFITS OF AEROPONICS:
Round the year cultivation: Since plants are grown in a controlled environment
crops can be grown year-round without being dependent on the weather or
atmosphere conditions outside.
Fast plant growth: Plants grow fast because their roots have access to a lot of
oxygen.
Easy system maintenance: In aeroponics, all you need to maintain is the root
chamber (the container housing the roots) which needs regular disinfecting, and
periodically, the reservoir and irrigation channels.
Less need for nutrients and water: Aeroponic plants need less nutrients and water
on average, because the nutrient absorption rate is higher, and plants usually
respond to aeroponic systems by growing even more roots.
Mobility: Plants, even whole nurseries, can be moved around without too much
effort, as all that is required is moving the plants from one collar to another.
Requires little space and high yield: Aeroponic systems can be stacked up in
layers to build vertical farms that take up much less space than traditional farming
methods.
Great educational value: Plants and root growth study in laboratories is easier for
students and researchers.
Proper root growth: In this system, plant roots have proper space to grow well. So
they don’t stretch or wilt.
No transplantation shock: Plants can be shifted to any growing media system
without any transplantation shock after root development.
Easier fruit harvest: Fruits produced from the system are easier to harvest.
Disease free produce: Due to clean and sterile growing conditions, plant diseases
and infections reduce up to agreat extent.
Production at moon stations: Using this technique, fruits can be grown at zero
gravity i.e at moon stations.
Potentially healthier and nutritious plants can be grown at homes; indoors or at roof
top.
Nurseries can propagate seeds and cuttings into healthy, harvestable plants in a
fraction of time of traditional methods.
Aeroponics systems can reduce water usage by 98 per cent, fertilizer usage by 60
per cent, and pesticide usage by 100 per cent, all while maximizing crop yields.
Power loss for a small period does not cause any damage to plants.
Key drawbacks of aeroponic technology
Every system has its drawbacks, and aeroponics is no exception.
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Dependence on the system: A typical aeroponics system is made up of high pressure
pumps, sprinklers and timers. If any of these break down, your plants can be
damaged or killed easily.
Technical knowledge required: Initially some training is required for system
maintenance. You need a certain level of competency in running an aeroponic
system. Knowledge of nutrients amounts required by your plant is essential, because
you don’t have any soil to absorb excess/wrong nutrients supplied.
Sanitary conditions of the root chamber: The root chamber must not be
contaminated, or else diseases may strike the roots. So you need to disinfect the root
chamber every so often. Hydrogen peroxide is often used as disinfectant.
High cost: Most aeroponic systems are not exactly cheap. Aeroponic systems may
cost many hundreds of dollars each.
Power loss: For a long time period power loss may cause irreversible damage.
CONCLUSION
Water plays an important role in the world economy. Approximately 70 per cent of the
fresh water used by human goes to agriculture. Out of that 45 per cent is wasted due to
gaudy irrigation techniques. By using aeroponic systems, we can save 98 per cent of
total water because of recirculatory system. Fresh, clean, healthy, efficient and rapid
food production can be obtained from aeroponic systems throughout the year. This soil-
less culture can overcome all the constraints that are present in soil culture production.
Enhanced disease-free yield leads India to be at top growers and exporters in near
future. Aeroponic system has the potential to produce enhanced vegetative growth
without use of any artificial hormones, pesticides or insecticide. Aeroponics is still a
good way to learn how to master plant growth and learn about their needs, within a
controlled environment. For urban dwellers that live in apartments, sometimes
aeroponics is the only practical way to garden. And on arid lands, aeroponics
circumvents this problem, and provides the best means of growing plants effective.
FUTURE PROSPECTS
Soilless cultures consider as a new developed technique for agriculture development
but it is not simple technique. However, there is lack of technical background of the new
technique among growers and horticulturists in many countries and well trained
employs are needed. Moreover, most substrates are internationally markets, so they are
expensive. Therefore, it is better to look locally about not expensive good substrates.
The growers can adept the soilless systems according to their needs, the place of the
system and according to their potential cash. The system in any case need to take strong
care and observation for the parameters needed for the good growth of the plants such
as nutrient concentrations, light, oxygen around the plants root zone, water quality, pH,
disinfection, temperature of the solution and more. Aeroponics helps conserve water,
land and nutrients, so the aeroponics system is the way of the future, making cultivation
of crops easier.
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