Soilless Agriculture a New and Advanced Method for Agriculture Development: an Introduction
Kaei-Kazzaz1 and AA El-Kazzaz2*
1Agricultural Engineer, Head of Hydro Valley Company, Cairo, Egypt
2Department of Plant Biotechnology, National Research Centre, Egypt
Submission: December 19, 2016; Published: January 04, 2017
*Corresponding author: AA EI-Kazzaz, Department of Plant Biotechnology, National Research Centre, 12622, Dokki, Giza, Egpyt,
How to cite this article: Kaei-Kazzaz, A El-Kazzaz. Soilless Agriculture a New and Advanced Method for Agriculture Development: an Introduction. Agri Res & Tech: Open Access J. 2017; 3(2): 555610.. DOI: 10.19080/ARTOAJ.2017.03.555610
Agriculture out of the soil is to use any means that will cultivate and plant development without entering the soil as a mediator for agriculture, where cultivated plants in isolation from the soil as long as the system used allows to strengthen the plants and provide water needed for growth and nutrients as it is the system followed for growing plants in the natural soil environment with irrigated nutrients intravenously instead of plain water and may be used a solid material such as gravel, sand, peatmoss, perlite and vermiculite in some cases as supporting mediators. Agriculture outside of soil is including hydro agriculture (Hydroponics), aqua agriculture (Aquaponics), aerobic agriculture (Aeroponics) as well as agriculture using supportive mediators. Benefits of soilless cultures include the reservation of cultivated lands for main crops; save not less than 90% of irrigated water; use nearly recycled fixed amount of water; most vegetable crops succeed and give the highest productivity in soilless agriculture than the ordinary agriculture; It can be run in various places such as balconies, roofs of buildings, various greenhouses and lands unsuitable for cultivation; the provision of fertilizer materials, where it’s used rationed amounts calculated accurately nutrients according to the plant requirements; Ease of dealing with plants and ease of conducting the required protection operations against various pests; Despite the increase in the constituent unit cost of soilless culture, but the large amount of production offset this cost in a short time. Soilless culture is a method of cultivation of new and advanced and requires us to search for human cadres have the ability to qualify for this work and is a rare, unfortunately.
Although several published works on cultivation plants in soils, few of these concentrate on planting plants in soilless cultures. The presented work is an overview of the systems of agriculture out of the soil. However, soilless agriculture offer a way to overcome the shortage of the normal amount of water needed to grow plants. Agriculture without soil, in fact, historically dates back to several hundred years BC since the civilization of ancient Egyptian, the Chinese and other cultures . The Aztecs started a method of suspended gardens based on hydroponics at Lake Tenochtitlan during the 10th and 11th centuries [2,3]. There are various techniques of soilless agricultures have being recently used. Such techniques are including Hydroponics, Aquaponics, Aeroponics as well as agriculture using supportive mediators. The soilless agricultures can be accessed on various kinds of places such as balconies, roofs, greenhouses and lands unsuitable for cultivation. Such kinds of agriculture operate under control conditions in order to obtain higher productivity and higher incomes. Despite the rise within the constituent cost of soilless culture, however the massive quantity of production offset this value in an exceedingly short time. Soilless culture could be a technique of cultivation of recent and advanced and needs to go looking for human cadres have the power to qualify for this work and could be a rare, sadly. In this regard, it will be reviewed these techniques briefly focus on the following paragraphs.
As it was remembered in introduction, soilless agriculture was used and recorded in several ancient civilizations but no information was recorded about it. However, the earliest published work on growing terrestrial plants without soil was the 1627 book, Sylva Sylvarum by Sir Francis Bacon, father of the scientific method, which he nominated it “water culture”.
However, Robert Boyle, the Irish scientist, in 1666 had been
described the first experiments on growing plants with their
roots submerged in water. In 1699, John Woodward published his
water culture experiments with spearmint and found that plants
in less-pure water sources grew better than plants in distilled
water. Mineral nutrient solutions for soilless culture of plants
were first perfected in the 1860s by the German botanists, Julius
von Sachs and Wilhelm Knop through experiments conducted at
1842 and 1895 respectively. The first proposal for a commercial
water culture system was made in 1929 by Professor William
Frederick Gericke of the University of California at Berkeley. The
term ‘‘hydroponics’’ was coined by Gericke 1937 to describe
the growing of crops with their roots in a liquid medium.
Moreover, in 1940 Gericke wrote the book, Complete Guide to
Soilless Gardening. However, two others of plant nutritionists
at the University of California named Dennis R. Hoagland and
Daniel I. Arnon since 1938 had developed nutrition solution
named Hoagland solution used for hydroponics until now. Since,
1930, on Wake Island, a rocky atoll in the Pacific Ocean used as
a refueling stop for Pan American Airlines, Hydroponics was
used to grow vegetables for the passengers. Hydroponics was a
necessity on Wake Island because there was no soil, and it was
prohibitively expensive to airlift in fresh vegetables. In the 1960s,
Allen Cooper of England developed the Nutrient Film Technique.
In recent decades, many companies world widely are appearing
and strongly working in soilless agriculture. Moreover, NASA
has done extensive hydroponics research for their Controlled
Ecological Life Support System (CELSS) [1-6].
Soilless culture is a man-made suggests that of providing
plants with support and a reservoir for nutrients and water. In
this regards, Savvas et al. , reported that Soilless culture can be
defined as “any method of growing plants without the use of soil
as a rooting medium, in which the inorganic nutrients absorbed
by the roots are supplied via the irrigation water”. The only and
oldest technique for soilless culture may be a vessel of water
during which inorganic chemicals melted (nutrient solution) to
produce all of the nutrients that plants need. Typically is known
as solution culture or water culture.
The function of soilless cultivating method is stimulating
plant growth while controlling the quantities of water, mineral
salts and most important, dissolved oxygen. The basic concept
is quite simple. When roots are suspended in moving water,
they absorb food and oxygen rapidly. If the oxygen content
is insufficient, plant growth will be slow. But if the solution is
saturated with oxygen, plant growth will accelerate. Therefore,
the grower’s task is to balance the combination of water,
nutrients, and oxygen, with the plan’s needs, in order to
maximise yield and quality. For the best results, a few important
parameter need to be taken into account; temperature, humidity
and CO2 levels, light intensity, ventilation, pH and the plant’s
genetic make-up. Essentially this is what any conscientious
gardener would do. Agriculture outside of soil is including hydro agriculture (Hydroponics), aqua agriculture (Aquaponics),
aerobic agriculture (Aeroponics) as well as agriculture using
supportive mediators. However, In Soilless culture plants did not
need soil but they need to be supplied with minerals Nitrogen
(N), Potassium (K), Phosphorous (P), Calcium (Ca), Magnesium
(Mg), Sulphur (S), Iron (Fe), Manganese (Mn), Copper (Cu), Zinc
(Zn), Molybdenum (Mo), Boron (B), Chlorine (Cl) and vitamins
also they need water, light, carbon dioxide, oxygen at their root
zone. It is an art.
There are two main types of soilless culture; closed soilless
culture and open soilless culture.
Closed soilless culture type: In closed soilless frameworks
the dissolved supplements are recycled and the supplement
concentrations are observed and balanced in like manner.
Keeping the supplement adjust in such hydroponic frameworks
is a test and the dissolved supplements must be examined
and dissected in any event once every week. The dissolved
supplements must be balanced by results. If there is not oversaw
appropriately, the dissolved supplements may escape of the
balance. Closed soilless frameworks incorporate both basic and
advanced soilless culture frameworks.
Open soilless culture type: In open soilless frameworks a
new dissolved supplements is involved for every irrigation cycle.
The dissolved supplements are normally conveyed to the plants
utilizing the dripping framework. In open soilless frameworks a
sufficient keep run-off must be kept up with a specific end goal to
keep supplement adjust in the root zone. Every soilless culture
utilizes just the substrates and dribble frameworks are has a
place with open soilless culture. However, there is a drip system
used as closed system in case of use reservoir for recirculating
the nutrient solution.
The following systems are belonging to closed soilless
culture in brief
Hydro agriculture (Hydroponics): Hydroponics (i.e., “water
working”) is simply the growing of plants without soil. Plants
don’t need soil, but they do need the vitamins and minerals that
soil can provide for them. Plants also need light, water, carbon
dioxide and oxygen at the root zone. In hydroponics, plants are
grown in an inert medium such as rocks or coco coir fiber, and
they are fed a solution containing a perfected mix of primary,
secondary and micro-nutrients. Almost any kind of plant can
be grown hydroponically, including veggies, herbs, fruits and
flowers. Hydroponics is world widely used by farmers and
Hydroponics provides an advantage over soil growing for
several reasons [7,8]. Plants can be grown year-round since
climate conditions can be controlled in a greenhouse. Because their roots do not need to reach for nutrients, the plants can
be grown closer together. The plants grown are significantly
larger because of so many available nutrients and not having
to waste time growing extensive root systems. This makes the
yields bigger. The nutrient solution also keeps the same amount
of nutrients available all the time, whereas soil tends to “wear
out” as the nutrients are taken up. The combination of all these
things makes hydroponics plants more productive than soil
growing plants. Many farmers in various places are beginning to
switch over to hydroponics for all of these reasons. The concern
about water use is also big reason hydroponics is becoming
more popular - it significantly conserves water over the usual
growing methods. The following Figures from 1 to 5 show
some of the kinds of hydroponics mainly used, but any person
can put his own design according to his need and the kind of
plants according to the main target and the aim of hydroponics
function. The following is a brief of five systems are mainly used.
Wick system: The wick system (Figure 1) is the simplest of
all types of hydroponic systems. That’s because traditionally it
doesn’t have any moving parts, thus it doesn’t use any pumps or
electricity. However, the wick is the connecting part between the
potted plant and food solution in the existing reservoir. Because
it doesn’t need electricity to work, it’s also quite useful in places
where electricity can’t be uses, or is unreliable. The wick system
is an easy type of system to build when first learning about
hydroponics, and/or you just your want to get your feet wet first.
This type of hydroponic system is also often used by teachers in
classrooms as experiments for kids. In wick system the plants
are cultivated in substrate.
Nutrient film technique (NFT): The nutrient film technique
(Figure 2) is recirculated design to run highly oxygenated
dissolved nutrients continuously over the roots of plants
through a set of channels, typically grown in baskets hanging in
a PVC pipe. The solution is pumped from a holding tank, through
irrigators at the top of every sloping pipe and the run-off from
the bottom of the channels is returned to the tank. Thus, the
nutrient solution is continuously recycled. It is possible to make
the angle of the pipe smaller and add an overflow pipe similar to
what’s in an off and flow system. This would serve to provide a
reservoir of nutrients that would remain in the event of a power
or pump failure. Because of the confined space of a PVC pipe and the requirement for nutrients to continuously flow over the
roots, the nutrient film technique is particularly well suited to
plants that have small root balls such as lettuce, strawberries,
Water culture or deep water culture (DWC): Water
culture or deep water culture is the straightforward form of
hydroponics systems (Figure 3). Plants are floating by float
platform on a bath of hydroponic nutrient solution. Oxygen is
supplied by an air pump that runs continuously. A water culture
system can easily be set up in glass basins, (fish ponds), plastic
boxes, ice boxes, Concrete basins or in engraved basins covered
with polypropylene sheets. Since the plants are floating and
continuously in contact with the nutrient solution, there is no
risk of damage to plants in the event of a power outage or stop
the air pump. The most convenient plants in this system are
Lettuce, strawberries, and herbs grow particularly well in this
Drip system: Drip hydroponic system (Figure 4) is at least
two containers, one on top or higher than the other. Plants
are located in the top container, while the nutrient solution is
in the bottom container. The nutrient solution is pumped up
to drips located by the stem of each plant with a water pump,
and an aquarium air stone is used to oxygenate the water. The
nutrients filter down to the plant roots and are passed back to
the bottom container. Typically both the water and air pumps
run continuously with this type of system. A crop of almost any
plant will grow well with this system. Plants with large root balls
are particularly suited to drip systems. However, the plants are
grown in supportive mediators.
Ebb and flow systems: Ebb and flow system (Figure 5) is
another inexpensive type of hydroponic setup. The setup is very
similar to the drip system, where there are two containers, the
one on top containing the plants in pots with substrate, and
the one on the bottom containing the nutrient solution. Rather
than the nutrient solution being passed slowly to drippers at the
stem of each plant, the nutrients are pumped in large volumes
into the top container, flooding the container. An overflow pipe
determines the height of the nutrients, typically to where the
roots begin at the base of the stem, with excess liquid being
recirculated through the overflow pipe back to the bottom
container. With ebb and flow system, the pump is switched on
and off intermittently (perhaps 30 mins on, 15 mins off), to flood
the grow tray periodically. When the pump is switched off, all of
the nutrients are siphoned out of the grow tray via the pump line.
The emptying period allows for oxygen to reach the roots, and
for this reason an air stone is not absolutely required for ebb and
flow systems. As with drip systems, almost any plant will grow
well with this type of system. Plants with large root balls are also
particularly suited to off and flow systems.
The aeroponics system is belong to closed soilless culture
system (Figure 6) is probably the most high-tech type of
hydroponics system . In this system sealed root chambers
used as reservoir for nutrient solution and the plants above
the reservoir cover (polystyrene or other material) must be
supported or hanged through holes in the expanded cover, hence
the roots hang in the air under the reservoir cover and are misted with nutrient solution found in the reservoir by stressful pump
to cover all area around the root with nutrient solution mist. The
misting is usually done every few minutes around the hanged
roots. 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
In this system, nutrient solution sprayed as a fine mist in
sealed root chambers. The plants are grown in holes in panels
of expanded polystyrene or other material. The plant roots
suspended in midair beneath the panel and enclosed in a
spraying box. The box sealed so that the roots are in darkness
(to inhibit algal growth) and in saturation humidity. A misting
system sprays the nutrient solution over the roots periodically.
The system normally turned on for only a few seconds every 2-3
minutes. This is sufficient to keep roots moist and the nutrient
There are three sorts of aeroponics frameworks. The first
framework is high pressure aeroponics frameworks don’t
generally utilize a water pump because of the various cycle
(on/off) times required. They as a rule comprise of a two sided
tank with an elastic divider. The supplement arrangement is in
one side and air in the other. At that point an air compressor is
utilized to pressurize the tank. A water line from the supplement
arrangement side races to the clouding heads, and a solenoid
is utilized to open and close a valve in the water line at exact
times utilizing a cycle clock. The genuine aeroponics framework
utilizes high pressure (60-90 psi). The second framework is low
pressure aeroponics frameworks (soakaponics) are what the
vast majority are alluding to when they say aeroponics. Low
pressure frameworks utilize standard submersible water pumps,
yet at the same time require a decent measure of water weight
or the water will simply stream out of the sprinkler/mister
heads. The more sprinkler heads you’re utilizing, the more water
pressure you will require. Sadly submersible pumps don’t give a
psi rating to look at. They just give you gallons every hour (GPH) and head tallness, and GPH is a measure of volume, not pressure.
Your best pointer of water weight is the “head stature” rating.
It takes pressure to pump water up, so the more GPH it can
pump higher, the more water pressure it will have. In any case,
the vast majority allude to low pressure splashing frameworks
as aeroponics frameworks as well. The third framework is
Ultrasonic foggers that make a fog in aeroponic frameworks.
While they do make a fog with a little water bead measure, there
is next to no genuine dampness in the fog/mist. The fog made
from ultrasonic foggers likewise tends to drop to the base of the
holder. Ensuring the roots is totally secured by the fog constantly.
Another issue with utilizing foggers is that the plates tend to stop
up with mineral form. The main plates that have appeared to
work with any dependability are the more costly Teflon heads.
They can once in a while be cleaned utilizing white vinegar, or
dilute and pH, and wiping them off with a Q-tip. A few producers
have joined utilizing ultrasonic foggers alongside the low weight
aeroponic plan in a similar framework .
Aquaponics is a system of aquaculture (Figure 7) in which
aquatic animals such as snails, fish, crayfish or prawns are
grown in tanks with combination of hydroponics in which
plants are grown in water in a symbiotic environment [9-
11]. In aquaculture, the aquatic animal’s excretions are raised
and accumulated in the water, increasing toxicity according to
ammonia foundation as toxic byproducts for aquatic animals;
hence, the aquaculture must be cleaned from that toxic material.
In an aquaponics system, water from an aquaculture system is
passing to hydroponics system where the toxic by-product are
broken down by Nitrifying bacteria that live on the surface of
the grow bed media initially into nitrites and subsequently into
nitrates, which are utilized by the plants as nutrients, and the
water is then cleaned and passing back to the aquaculture system.
However, the used water passed through a biofilter a place where
the nitrification bacteria can grow and convert ammonia into
nitrates, which are usable by the plants. As existing hydroponic
and aquaculture cultivating procedures constitute the foundation
for all aquaponics frameworks, the size, complication, and sorts of foods grown in an aquaponics framework can differ as much as
any framework found in either particular cultivating discipline.
These are the most commonly used type of aquaponics systems;
1- Media filled beds are the simplest form of aquaponics, they use
containers filled with rock medium of expanded clay or similar.
Water from a fish tank is pumped over the media filled beds,
and plants grow in the rock media. This style of system can be
run two different ways, with a continuous flow of water over the
rocks, or by flooding and draining the grow bed, in a flood and
drain or ebb and flow cycle. 2- Nutrient Film Technique (NFT)
is a commonly used hydroponic method, but is not as common
in aquaponics systems. In NFT systems, nutrient rich water is
pumped as very thin film down small enclosed gutters. Plants sit
in small plastic cups allowing their roots to access the water and
absorb the nutrients. NFT is only really suitable for certain types
of plants, generally leafy green vegetables, however, larger plants
will have root systems that are too big and invasive, or they
become too heavy for the lightweight growing gutters. 3- Deep
Water Culture (DWC), works on the idea of floating plants on top
of the water allowing the roots to hang down into the water. This
can be done in a number of ways. This method is one of the more
commonly practiced commercial methods. DWC can be done
by floating a foam raft on top of the fish tank; however a more
common method is to grow the fish in a fish tank and pump the
water through a filtration system, and then into long channels
where floating rafts filled with plants float on the water surface
and extract the nutrients. However, this system is considered as
closed soilless culture whereas a recirculating system for the
nutrient solution is occurred.
Figure 7 clears the target steps of Aquaponics culture with
hydroponics deep water culture (Can be replaced by NFT system
or Media filled beds system or all systems together can be
Growth medium is the substitute for soil in soilless culture
systems. In this system, a solid medium provides support for the
plants. The functions of growth medium are to provide the roots with oxygen bring the water and dissolved nutrients in contact
with roots via irrigation system through the media, allowed to
run to waste to recirculate the solution through the system and
to steady the plants as supportive mediators so that they do not
fall over. There are various substrates (Figure 8) that used as
growth medium are consisting of inorganic (natural; expanded
clay, glasswool, gravel, perlite, pumice, rockwool, sand, sepiolite,
vermiculite, volcanic tuff and zeolite or synthetic; foam mats,
hydrogel and plastic foam) or organic (bark, coconut coir, coco
soil, fleece, marc, peat, ruffia bark, rice husk, sawdust and wood
The substrate culture systems divided according to
drainage procedure into the following two major systems .
As remembered before, in most soilless cultures that used
substrates without reservoir for recirculating the nutrient
solution are belong to open soilless cultures, therefore, more
care about the feeding the plants must be taken because the
irrigation water with the supplements dominantly lost. The
open substrate culture seems to be more promising due to its
high adaptability to the farmers’ conditions [14,15]. In countries
where hydroponics is applied commercially, open hydroponics
cultivation systems have created pollution problems resulting in
a consequent transition to closed systems. The closed substrate
systems increase water, nutrient and pesticide use efficiency and
decrease their impact on the environment but a specific system
needs to be developed for each crop [16,17].
Properties of substances used in soilless culture: There
are many stuffs are used for building the growing systems
for soilless culture, such as asbestos, aluminum, concrete,
corrugated sheets, polyethylene, polypropylene, polystyrene
foam, PVC, steels and any material that comes to mind. All these
stuffs must have sustainability characteristics .
Technical specifications of the materials used to create
the systems: However, the specifications of these materials
must exhibit the followings; 1- No outflow during installing and
usage process and possibility of evaluating possible outflows.
2- No damaging volatilization of damps or substances. 3-
Resistance to vapor that used for sanitation, UV radiation and
pesticides. 4- Ensure rewind materials to suppliers for recycling.
5- Low costs. 6- Have no reactions with each other’s or any used
solutions (inert). 7- Also, Metallic materials must be coated with
weatherproof materials against interact with any solid materials,
liquid or gaseous.
Technical specifications of supportive substrates: Often
hydroponics as a technique of soilless culture is using only water,
with no substrate. This is true for NFT or Aero-hydroponics,
which use no media, or just enough to act as a plant support. But
growers working with Drip Irrigation, Deep Channel NFT, or Ebb
and Flow, will use more or less supportive substrate depending
on the growing system they choose. Supportive substrates must
have the following properties 
1- Aeration and drainage. 2- Applicable in natural form
without need for processing. 3- Can be mined or produced by
the industry. 4- Cation exchange capacity (buffering action). 5-
Easy to use and Environmental and health hazards. 6- Free from
grit, heavy metals and radioactive pollutants and Cleanliness. 7-
Has constant quality (no decrease of physical properties during
use). 8- Having a lifespan for at least three years. 9- Hydrophilic.
10- Inert (no reaction with the nutrients). 11- Low cost. 12-
Low density. 13- Have neutral pH. 14- Porous. 15- Recyclable
or destroyed without hazard. 16- Resistant for sterilization
several times without structural quality change. 17- Pest free.
18- Stability of organic matter. 19-Have water retention capacity
and water to air ratio.
Another essential aspect to keep in mind is the close
relationship between the supportive substrate and the irrigation
cycles applied whereas some of them will retain much more
moisture than others. Many supportive substrates are in the
markets that meet the above demands with label specifications.
Many factors, such as nutrition, light, heat, air, pH and salinity
affect plant growth, whether it was developing in the soil or soilfree
systems. In agriculture without soil Systems, nutrition and
water are permanently available to the plants, whether inside or
outside doors and therefore the plants never stressed. However,
in outdoor, the sun light and air are obtainable but for indoor
systems, adequate light sources such fluorescent lights, grolights,
Metal halide lamps or sodium vapor lamps must be used.
All soilless culture systems must provide available oxygen using
good air circulation at the root zones to keep them alive. Healthy
roots which are white in color are responsible for absorption
of nutrients and water for growing the plant. However, it must
be good air circulation for the indoor systems around the plant
leaves to carry out the photosynthesis. However, root zone must
be worm enough to keep the root zone to 20-22 C° as possible to
prevent ant disorder can be done for the cultivated plants.
The success or failure of agriculture without soil depends
on the existence of balanced nutrient solutions and appropriate
for all stages of plant growth. Agricultural fertilizers are
sold through stores that sell agricultural products and must
choose the right fertilizer for soilless cultures that contain all
13 elements necessary for plant growth. It is crucial to follow
instructions of the dilution rate recommended on the label and
to test the recommended solution to be sure the pH is between
5 and 6. Simple pH test kits and pH modifiers are available
wherever fish supplies are sold. Depending on the stage of plant
development, some elements in the nutrient solution will be
depleted more quickly than others. Therefore, it is appropriate
to measure the lack of elements of the farming system without
soil every two weeks, and to provide this shortage, also, make sure that the nutrient solution is kept at the original volume. It
must compensate the lack of water as the result of in the output
cultivated plant consumption and as a result of evaporation
during cultivation time in the system. Due to lack of water in the
system, the concentration of nutrients is increase and can harm
the root system and its function, therefore, it must compensate
for this deficiency by adding new clean filtered water to raise
the nutrient solution to its original concentration. Be sure to use
nutrients designed for Hydroponics in a Hydroponic system. The
composition of elements in nutrients designed for soil is very
different from that for Hydroponics because soil grown plants
get most of these elements from the soil. With Hydroponics there
is no soil to get the elements from, so the two are very different
in composition because they are not designed to be a complete
plant food and they may not water-soluble. For example,
Nitrogen in the form of urea is not immediately available to a
plant in hydroponics because urea is not soluble in water. For this
reason Nitrogen must be delivered in its Nitrate form in order to
be utilized in hydroponics. One thing that is often over looked
when it comes to nutrients is the nutrient solution temperature.
The roots of plants grow underground in nature and to duplicate
what they would receive in nature it is very important to keep
the root zone to 20 - 22 °C. That’s not to say if the nutrient temp
reaches 23 °C or 23.5 °C the plants will die, but it should be kept
as close to 20 – 22 °C as you can. Plants with nutrient tempters
too high can have problems including (but not limited to) flowers
turning yellow and falling off, damaged fruits and a lack of new
One of the main elements of the success of farming systems
without soil is water availability and quality. There are many
sources for water availability from lakes, rainwater, rivers and
underground reservoirs or from other treatments. However,
water must be of high quality free of pathogens as determinant
factors for the success of agriculture without soil .
One of the disadvantages of the closed systems is the risk of
a rapid dispersal of soil-borne pathogens by the recirculating
nutrient solution. To eliminate these pathogens, several
disinfection methods can be used and the followings are some
Ozone treatment can be used to disinfect the drain water.
Ozone is the second most powerful sterilants in the world and
its function is to destroy bacteria, viruses and odors. An ozone
supply of 10 g/h/m3 water with an exposure time of 1 h is
sufficient to kill all pathogens .
Another way to disinfect the drain water is the use of UVradiation.
Ultra-violet radiation (or UV) is a proven process for
disinfecting water, air or solid surfaces that are microbiologically contaminated. For eliminating bacteria and fungi an energy dose
is recommended of 100mJ/cm2. For viruses a dose of 250 mJ/
cm2 is recommended. The advised dosage of 100mJ/cm2 to
control Fusarium gave adequate control at 14% transparency.
However, at 8% transparency 110mJ/sq.cm was needed; and
at 4% transparency, more than 174mJ/sq.cm was required.
For Fusarium control, the grower has the option of diluting the
water, or increasing the UV radiation [21-23].
When heat treatment is applied, a solution is heated for
about 30 seconds to a temperature of 95˚C. At this temperature
all pathogens are killed . A disadvantage of heat treatment
is the consumption of gas. Also warm drain water contains less
For several years commercial growers have used a slow
sand filtration installation to eliminate pathogens [23-27]. Sand
filtration is frequently used and a very robust method to remove
suspended solids from water. The filtration medium consists of a
multiple layer of sand with a variety in size and specific gravity.
Sand filters can be supplied in different sizes and materials both
hand operated or fully automatically.
In agriculture, the principle application is as a biocide,
signifying ‘life-executing’ specialist. It is utilized to split down
the foul develop in hydroponic lines that frequently contains
microorganisms, contagious spores and different organisms. It
is likewise utilized effectively for sterilization of seeds, blooms,
organic products, vegetables, hardware and packing materials.
Sooner rather than later it might be utilized for malady control
as a part of nurseries. The official term for this procedure is
Anodic Oxidation (AO), and the machine that makes electrolysed
water is an AO-unit. Different names for electrolysed water
incorporate EW, hydrolysed water, electrically enacted water,
electrochemically delivered water, actuated water, dynamic
water (and that’s only the tip of the iceberg) .
Hydrogen peroxide treatment is a much less expensive
contrasting option to ozone, UV and layer filtration sterilization.
Be that as it may, it is a feeble oxidator. While the execution
is enhanced by including a powerless corrosive, it is still not
sufficient to take out all pathogens. High measurements (400
ppm) are expected to take out infections, however it was found
that a little rate of nematodes survived treatment (0.3%), and
these were fit for tainting plants. There are a few hydrogen
peroxide items available have great impact for particular
pathogens including Pythium and Fusarium .
Membrane filtration can be separated into inverse osmosis
(RO), hyper-, nano-, ultra- and micro-filtration relying upon the pore measure of the membrane. They are costly and inclined
to gagging after some time. Remedy pre-treatment of supply
water is fundamental to expand the life span of membranes. The
predetermined necessities were that the micro-filtration unit
should have been ready to treat no less than 20,000L/day and to
screen to a pore size of 0.2 microns. Microfiltration is practically
identical in expenses to synthetic treatment alternatives however
without the potential perils and without affecting on the nutrient
solution. In any case, microfiltration seems uneconomical for
smaller enterprises .
Chlorination is the most widely recognized type of cleansing
utilized by hydroponic cultivators. It is cheap and promptly
accessible. Chlorine is the only biocide that can be lawfully
added to nutrient solution. Calcium hypochlorite (Ca(OCl2)),
normally known as ‘pool chlorine’, is the most widely recognized
disinfectant utilized by the producers. Without going into the
science, chlorine’s capacity to slaughter smaller scale living
beings comes about because of its solid oxidizing power and
the interruption of the working of the miniaturized scale living
beings. However, if the chlorine sufficiently strong, it will
execute all pathogens with which it comes into direct contact.
This is useful for cleaning water and recouped nutrient solution.
However, the used concentration must be acquired because if it
is used at highly strength, it will also attack and kill plant roots.
Moreover, it is not systemic so it won’t kill systemic pathogens
which have attacked plant roots creating sickness .
Production augmentation: The application of soilless
culture approximately increases the yields as the result of the
precise control of the growth elements to the plants such as
nutrition, pH, oxygen, carbon dioxide, light and temperatures.
However, increasing the yield using soilless cultures will help the
offset the initial and any additional costs of the soilless cultures.
Soilless culture produced vegetables can be of high quality and
need little washing.
Water control: In most kinds of soilless culture the uses
of irrigation water are accurately controlled with extremely
less amount as compared with normal irrigation in the case of
traditional soil cultures. It save much needed labor and time for
checking, cleaning irrigation nozzles and frequent examination
of trippers which easily can be blocked by calcium carbonate
or other compounds that can be eliminated by acidification of
nutrient solution or by pretreatment of irrigation water and that
need more costs, labor and time.
Monitor of plant nutrition: The nutrition elements are
used as solution forms in accurate amounts as the plant needs and not in Hugh amounts as in the normal plantation. In soilless
culture, the harmful elements to plants above certain dosages
can be kept within safe dosages. However, there is distribution
uniformity of nutrition elements only for all the plants in water
cultures. PH and E.C. of the nutrient solution can be controlled
according to the requirement of the crop and environmental
conditions and that is strongly difficult and expensive in the case
of normal soil cultures.
Purge practices: Soilless culture is occurred under
controlled conditions and that led to avoid spreading of weeds,
diseases and insects therefore no need for using the pesticides
which finally pollute the environments as used in soil cultures
and that mean less labour and less costs.
Monitor root surroundings: In soilless culture, it is easily
to control the surrounding environmental and root temperature
and supplying roots by oxygen.
Crop diversity: In soilless culture, the interval time between
crops is nearly null set because the absence of cultivation
operation as in soil cultivation therefore, multiple crops
cultivated per year and that mean increasing income.
Agriculture of land inappropriate: Agriculture without soil
provides an idealistic process for plant cultivation when there is
no appropriate land empty of pathogens and salinity is available.
Alleviation of labor requirements: In soilless culture, all
cultural practices of soil cultivation such as soil sterilization,
weed control and others can be excluded in soilless culture and
that save the labor input and the needed time of work.
High capital investment: The initial cost of building the
system of soilless culture is high, but the fast and big yield
production offset such costs rapidly in the firstly 3-4 years from
the beginning of the system if all things running ok.
The shortage of technicians and skilled labor: Agriculture
without soil suffers from a shortage of workers and trained
The risk of Pathological Injuries: Morbidity in open
systems of soilless culture is few whereas in closed systems be
great and that need a big care and strong sanitation.
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
In conclusion, one might say that, there is extensive advance
has been made as of late in the improvement of monetarily
suitable soilless systems and there is a generally wide business
applications now in Countries that applied farming innovations.