Zikhona Buyeye, a junior researcher on the Agricultural Analysis Council’s Pure Sources and Engineering Division, explores the significance of vertical farming buildings for small-scale vegetable manufacturing.
Picture: Oregon State College/Flickr
A fast Web search of the time period ‘vertical farming’ produces photographs of seemingly futuristic buildings housing an abundance of luxuriant flora. Whereas these complicated architectural designs and cutting-edge expertise might sound far-fetched, vertical farming is, actually, a system that may be realised sooner somewhat than later.
The keys to reaching this dream in South Africa could also be present in simplification and downscaling. Actually, extra sensible and simply implementable designs might present options to the nation’s meals safety issues, in addition to the rising prices of manufacturing and transporting meals.
Small-scale vertical farming buildings, which predominantly make use of hydroponics, provide an achievable technique of enhancing agricultural productiveness.
When vegetation are grown hydroponically, their roots are immersed in a nutrient resolution somewhat than in soil. The important thing parts of such a system are a nutrient-solution reservoir, a construction to deal with the vegetation, and a rising medium to anchor them. Optionally available components can embrace a nutrient recirculation pump, an air pump and develop lights.
Lively hydroponic techniques
Hydroponic techniques might be both lively or passive, and range in complexity. In an lively system, a pump is used to recirculate the nutrient resolution.
Widespread examples of lively techniques are the drip system, the flood-and-drain system, and the nutrient movie approach (NFT).
In a drip system, the nutrient resolution is pumped from the reservoir and drips onto the rising media, from the place it drains right down to the vegetation’ roots and is recirculated.
With a flood-and-drain system, the vegetation are stored in a reservoir that’s routinely flooded with the nutrient resolution. The answer is then drained, permitting contemporary air to flow into across the vegetation’ roots. The size of the flood- drain cycle is dictated by the vegetation’ necessities.
In an NFT system, the vegetation sit in a tray and a skinny movie of nutrient resolution is circulated continually round their roots. As this technique makes use of minimal quantities of water and vitamins, it’s extremely environment friendly.
Passive techniques
Passive techniques don’t use pumps, which signifies that the nutrient resolution is just not circulated across the vegetation’ roots. As a substitute, the roots are immersed immediately within the static nutrient resolution, as within the Kratky technique.
Alternatively, the nutrient resolution might be drawn to the plant roots with out utilizing a pump, as is the case in a wick system. Air pumps might be added to the reservoir to assist root aeration.
In small-scale vertical farming, hydroponically grown vegetation are sometimes housed in buildings manufactured from PVC pipes. Designs embrace vertical or horizontal A-frames, columns, stacked beds, vertical towers, and stacked trays. The kind of vegetation to be grown dictate the construction used.
Rising media
Since hydroponics and aquaponics use no soil, a substrate or rising medium is required to anchor the vegetation’ roots. You will need to select an inert substrate that retains moisture and permits for root aeration.
It’s not usually that these properties are present in a single rising medium, so a mixture of substrates are used to attain the specified final result.
Expanded clay pellets, vermiculite, perlite and rockwool are generally used rising media. Perlite and vermiculite are usually mixed in a 50/50 ratio, as the previous has a low water-holding capability but excessive air porosity, whereas the latter has a excessive water-holding capability.
Choosing the proper substrate is just not an actual science; it’s influenced by monetary and technical elements, and could also be primarily based on trial and error.
Totally different vegetation require totally different nutrient options. Gentle-duty fountain pumps can be utilized to flow into the nutrient resolution in small-scale techniques. Handbook or digital timers might be included into the design to manage water circulation in line with the vegetation’ water and oxygen wants.
Small-scale vertical farming
Small-scale vertical farming buildings can be utilized open air (offered they’ve appropriate protection), in tunnels, or indoors with various ranges of environmental management.
When vegetation are grown indoors, develop lights could also be added to the system to both complement pure mild or substitute it altogether. Handbook or digital timers can be utilized to regulate these lights.
Numerous varieties of develop lights can be found, with LED lights being the most well-liked with growers at current. LED develop lights might be manipulated to provide mild that’s solely within the photosynthetically lively radiation vary; in different phrases, solely the sunshine that’s obligatory for plant progress.
Compared with different develop lights, LEDs have an extended lifespan, are straightforward to regulate, emit solely a small quantity of warmth, and have very excessive working efficiencies. The price of LED develop lights is anticipated to lower with the event of the vertical farming business.
Rising vegetation vertically underneath managed environmental situations eliminates weather-related plant harm and permits for crop manufacturing all yr spherical. On the similar time, publicity to pests and plant illnesses is decreased.
Vertical farming might be carried out in city areas, thereby permitting the grower to be near his or her market. This implies a shorter provide chain and a decrease carbon footprint.
Rising vegetation in hydroponic, aquaponic and aeroponic techniques improves their high quality and yield, and reduces rising time and water use. Doing so vertically additional will increase yield.
Execs and cons
The event of the vertical farming business in South Africa might have social advantages, too, because it might result in employment alternatives. It additionally stands to draw extra younger folks to the agriculture sector.
For native farmers, the most important problem introduced by vertical farming is the results of the nationwide power disaster. An influence outage can result in wilting and drying out inside a short while, relying on the design of the construction used to deal with the vegetation.
Farmers ought to due to this fact contemplate investing in backup energy techniques or utilizing different sources of power, reminiscent of solar energy. The draw back is that each of those choices are capital-intensive.
Whereas the danger of pests and soil-borne illnesses is decreased, the circulation of the nutrient resolution will increase the danger of widespread plant harm as a consequence of water-borne illnesses. Preventative measures reminiscent of organic management, cleanliness and sanitation due to this fact must be rigorously utilized.
All issues thought-about, vertical farming has the capability to vary the course of meals manufacturing in South Africa. Implementing such techniques on a small scale might bridge the hole between our present struggles with standard farming and the advantages provided by complicated, large-scale vertical farms.
Typical agriculture stays a major contributor to local weather change. On the similar time, local weather change is making it more and more troublesome for farmers to provide good-quality crops with fewer inputs.
We have to make drastic modifications so as produce meals in a extra sustainable method. Maybe it’s time for small-scale vertical farming buildings to rise to the problem.
Electronic mail [email protected].
