Floating system for better nutrition
An innovative method of farming that improves the nutritional value of edible product. A survey conducted by the research group Experimental Company "La Noria".
The floating system (from the English to float, float) is an innovative technique of hydroponic cultivation.
It is a production system in static liquid medium in which plants are grown in polystyrene panels provided with slots which are filled with small quantities of inert substrate (vermiculite, perlite, etc..) Or in containers with recesses (number and size of the alveoli vary depending on the crop species), floating in tanks waterproofed of 30-40 cm in depth, filled with nutrient solution.
The use of the floating system, initially developed for the production of tobacco, has developed rapidly in the world of cutting other horticultural species (lettuce, spinach, chicory, lamb's lettuce), from bush (lettuce, endive, radicchio), from the root (radish) and aromatic (basil, arugula, chives, parsley, mint, sage, dill, borage).
This system of cultivation without soil has proved particularly suitable for the cultivation of vegetables for the IV range, because it is cheap (for manufacturing costs and management very limited), is able to ensure high levels of production and allows to obtain a product characterized with good quality features, clean and free of residual soil.
This technique has also been enhanced by the FAO (United Nations Organization for Food and Agriculture), which brought 
international attention through the exhibition of small units of cultivation, domestic level, the World Food Summit of 2002 in Rome. The idea is to promote, as part of Food for the Cities , the cultivation of vegetables in small enough units to achieve the objective of tire guarantee the availability of fresh vegetables daily, healthy and high nutritional value for family consumption and to provide a minimum income from the sale in the neighborhood.
In the cultivation in a floating system, in addition to the production parameters, growth and quality, was also evaluated the possibility of improving the nutritional value by means of enrichment of the product with nutrients "friends of Health" (iron, selenium, fatty acids w- 3). This represents an aspect of quality of leafy vegetables for the fresh-cut unexplored.
The capacity for accumulation of trace elements in vegetables is undoubtedly less than in other foods (potatoes, cereals), but getting a consistent increase of the content of some minerals is still beneficial, especially if you compare the bioavailability of the elements brought by the plant compared to supplements minerals.
A series of experiments conducted in greenhouses at the Experimental Farm "La Noria" Institute of Sciences of Food Production (ISPA), CNR, Bari, related to 4 species: spinach, lettuce mini-Roman lettuce and purslane, reared floating system, applying the treatments for the enrichment of edible product in the collection.
In particular, in spinach and lettuce mini-Roman were applied, respectively, 40 and 60 mg / L of Fe +3 by ammonium iron citrate (AFC), compared with the nutrient solution (SN) control containing 2 mg / L of Fe +3; in lettuce were administered 0 and 3 mg / L of Na 2 If by SeO 4, purslane were applied three reports NH 4: NO 3 (0: 100, 50: 50, 100: 0) in the SN to verify the influence on the accumulation of alpha-linolenic acid in the shoots.
In the leaves of lettuce iron is increased by 3, 2 to 4, 3 mg/100 g ww, and production increased by 18% with the adminis tration of iron, reaching 3, 7 kg / m 2. In spinach, compared to an average production of 1, 8 kg / m 2, was detected varies tion of the iron accumulated in the leaves (foil + petioles) of 30% up to the value of 2 mg/100 g ww
The application of AFC to the SN did not result in the appearance of toxicity symptoms in plants despite treatment and lasted 11 and 28 days respectively in lettuce and spinach.
The lettuce has produced an average of 3 kg / m 2, the accumulation of selenium in the leaves was 31 times compared to the untreated control, reaching a value of 193 mg/100 g of mp As regards the purslane, between the relationships NH 4: NO 3 studied, the most interesting answers enrichment in acid?-linolenic acid in the shoots were observed with administration of N-NH 4 in the SN (130 mg/100 g ww) compared to nitrate nutrition exclusively ( 69 mg).
But the best production results were obtained when nitrogen was distributed exclusively in the form nitrate (9, 2 vs. 8, 1 kg / m 2 of the ammonia form).
Overall, the iron content of 4, 3 mg/100 g of mp of lettuce is equal to 30% RDA indicated for iron, while it would be necessary to reduce the accumulation of selenium in valeria because its content was found to almost three times the RDA value.
Only for the acid to-linolenic acid content determined in purslane, on the shoot whole and not only on leaves, represents 10% of the quantity indicated RDA, which however refers to fatty acids w-3 in general.
As part of a program to encourage the consumption of vegetables, considered as foods rich in trace elements and substances protective of human health, the supply of enriched product would be a further incentive to the consumer. Especially when you consider the increased bioavailability of these elements when they come from plant sources and lower energy density of vegetables.
The incentive to the consumption of vegetables rich would be even higher if their properties were highlighted by a nutrition label. The possibility of a vegetable market with a nutrition label is attached to its packaging, like potatoes and onions or fresh-cut vegetables.
Micro system set up in floating gardens near the entrance of the building at the FAO World Food Summit (Rome, 10-13 June 2002)
Monia Charfeddine (monia.charfeddine @ entecra.it) - Research Unit for the cropping systems of hot-arid environments - CRA, Bari
Maria Gonnella (maria.gonnella @ ispa.cnr.it) - Institute of Sciences of Food Production - CNR, Bari
Julia Conversa (giulia.conversa @ agr.uniba.it) - Department of Agro-Environmental Sciences, Chemistry and Plant Protection - University of Foggia
Peter Santamaria (santamap@agr.uniba.it) - Department of Plant Production Sciences - University of Bari
Source: Agronotizie (CS) by Holly - Book Agrinnova.
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Tags: world hunger , floating system , research , cultivation techniques
December 17th, 2010 at 17:57
but these bowls with materials that are waterproof? not that can be toxic?
December 20th, 2010 at 24:38
The tanks are normally made of plastic, non toxic foods, such as hydroponic systems for home use.
December 20th, 2010 at 17:29
I read somewhere that you can use to waterproof polyethylene, what do you think? I'd like to create a space in my company for this type of cultivation serra.ma how do you control the various elements in the nutrient solution? that is usually EC value is measured, but this is just the value of its total, but if the plant absorbs more nitrogen than other elements such as how do you know? thanks
December 21st, 2010 at 17:23
Yes, I think that the EP is a suitable material.
We always measure the EC, does not change anything in this regard than the amateur hydroponic cultivation.
You can find some clarification to that effect
Here , where we talk about football.
The question does not change for the other elements, in practice deficiencies and nutritional problems in general are difficult to avoid and should be evaluated from time to time according to the symptoms (and even some 'trial and error).
A suitable growing environment (temperature, pH, ventilation, adequate irrigation) and a good fertilizer generally allow to obtain very valid results, and a bit 'of experience will do the rest
December 21st, 2010 at 19:44
thanks