Simplified Hydroponic Floating Systems for Vegetable Production in Trujillo, Peru F. Orsini, M. Fecondini, M. Mezzetti, N. Michelon and G. Gianquintoa Dept of Agro-Environmental Sciences and Technologies University of Bologna viale Fanin, 44, Bologna Italy Abstract Simplified hydroponic systems are a sustainable way for fruit and vegetable production in/for the cities. Small scale farming, both on a family and a community basis, may allow to achieve the goals of both improve nutrition and reduce poverty. A project for the development of soilless cultivation in mother groups was carried out between 2002 and 2004 in Trujillo, northern Peru. In this work we will present some results of a simplified soilless floating system, adopted for the cultivation of radish, lettuce, baby leaf lettuce, leaf beet and garden beet. The growing system, composed by a 1 square meter wooden structure, made waterproof through the application of a plastic film, and filled with nutrient solution hosted the floating alveolate polystyrene trays where plants were grown. The growing substrate was rice hulls. Yield of cropped species was about 3.2 kg m-2 cycle-1 (radish), 10.7 kg m-2 cycle-1 (lettuce), 6.3 kg m-2 cycle-1 (baby leaf lettuce), 5.4 kg m-2 cycle-1 (leaf beet), 3.6 kg m-2 cycle-1 (garden beet). An analysis of the economic value of gardening is also provided. INTRODUCTION Improving health condition allows to develop a more sustainable and stable economic growth at both family and community level. In peri-urban and rural areas of Latin America, health matters are frequently related to a lack of micronutrients and vitamins in the diet of the population (FAO, 2008). It is known that vegetables play a fundamental role in the human nutrition as source of minerals, vitamins and other antioxidant compounds, but in Brazil, as well as in other Latin America countries, the consumption of vegetables is very low as compared to Europe and North America. The low level of vegetable consumption is due to a lack of tradition in its cultivation and use, or simply because people have not enough money to purchase these products. On the other hand vegetables are agricultural products of high economic value, so may represent a means to enhance the income of small farmers. Thus, increasing the cultivation and the use of vegetables has potential to improve health condition and reduce poverty. Floating system is known as one of the simplest hydroponic systems and is particularly adapt to leafy vegetables. Among cropping systems floating is gaining interest for these kind of productions because it allows to overcome agronomic problems such soil-born disease, it is dynamic and flexible allowing to increase number of cycles and, thus, production. Furthermore, also quality can be enhanced because of the better hygienic-sanitary characteristics and the possibility to modulate plant nutrition so that nitrate continent is reduced (Zanin et al., 2009, Fontana et al., 2004). MATERIAL AND METHODS A project of international cooperation was conducted in 2003-2005 in the periurban area of the city of Trujillo, in the north of Peru. The activities were funded by the Veneto Region (Italy) and carried out by our research group in collaboration with the NGO Cesvitem, which already operated in the area with mother groups (so called Clubes de Madres) from several years in the framework of a project called pininos. Clubes participating to the pininos project would receive support in the measure of half the price a
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Proc. IInd Int’l Conf. on Landscape and Urban Hort. Eds.: G. Prosdocimi Gianquinto and F. Orsini Acta Hort. 881, ISHS 2010
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of the meal of the children attending the refectory, whereas the remaining half was partly provided from governmental support and partly from the mothers. This project consisted in the reduction of the food requirement of the group by the introduction of small scale hydroponic cultivation for the production of vegetables. Experiments were carried out between August 2003 and August 2004 in Trujillo (Peru), 8° 7' 0 S, 79° 1' 60 W. The research was conducted on commercial varieties of lettuce (Lactuca sativa Mill.), leaf beet (Beta vulgaris ssp. vulgaris convar. cicla), garden beet (Beta vulgaris ssp. vulgaris. convar. vulgaris var. vulgaris) and radish (Raphanus sativus), sold in the local market. The nutrient solution, called La Molina, was based on a standard solution prepared by the Horticultural Dept of La Molina University of Lima, using commercial hydro-soluble fertilizers. All fertilizers were locally available. The growing system was composed by a wood container of about 1 square meter, waterproofed with plastic film. A total of forty growing units were used for the experiments, ten for each crop. Seed were directly sown in the growing system and water was given with a watering can till the roots reach the nutrient solution. Plant density was 70 plants m-2 for lettuce, leaf beet and garden beet, and 100, 230 respectively for baby leaf lettuce and radish. During the growing period, EC and pH of the drainage nutrient solutions were daily measured (using Hanna HI99/000) for each crop. RESULTS AND DISCUSSION The Growing System Floating system allowed good production of different leafy vegetables and moreover advantages of this system was its lower starting and running costs (Table 1 and 2), which are respectively 70 Nuevo Soles (17 Euros) and about 7 Nuevo Soles (1.70 Euros) per month. La Molina nutrient solution gave good results, confirming previous experiences in the similar climatic condition with leafy vegetables (Rodríguez-Delfín et al., 2001). Electrical conductivity was 1.5 dS cm-1 at the beginning of the growing cycle, nutrient solution was concentrated when it reaches about 0.9 dS cm-1, pH ranges from 5.3 to 6.6. Yield of Hydroponically Grown Vegetables, Unit Cost and Income Table 3 reports results obtained in the trial. Lettuce yield was 10.7±0.2 kg m-2 and harvesting was 70 days after sowing (DAS). Therefore production can reach 51.4 kg m-2 yr-1, which is a good result considering that transplanting could improve this data by a better use of production modules area. Bradley and Marulanda (2001) produced 65 kg m-2 yr-1 using a similar system in Colombia. Mean yield of radish was 3.2±0.1 kg m-2, with about 10 cycles per year means 32.0 kg m-2 yr-1. Bradley and Marulanda (2001) reported 38 kg m-2 yr-1 for this crop. Garden and leaf beet last 4 month from sowing to harvesting, the latter produced more than the former (respectively 5.4±0.6 and 3.6±0.2 kg m-2 which corresponds to 21.6 and 14.4 kg m-2 yr-1). According to the income and the related unit cost per year, this production system seems to be feasible for leafy vegetables production in Trujillo context and moreover it is particularly adapt for being managed by not professional farmers. According to the presented data, lettuce, although with an higher unit cost, is by measure the most rentable crop (Table 3). The construction and the maintenance of the growing system were easily carried out by the groups involved in the project (Fig. 1). The time of return of the investment (Fig. 2) is extremely short (considering an interest rate of 5%) for lettuce, all costs are easily covered within the first year of activity whilst it takes longer for radish, leaf and garden beet (within two and three years). This data suggest that one crop (lettuce in this case) can be grown with market purpose and its good price and productivity could sustain crop diversification for family feeding.
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Literature Cited Bradley, P. and Marulanda, C. 2001. Simplified hydroponics to reduce global hunger. Acta Hort. 554:289-296. Caldeyro-Stajano, M. 2003. The family grown hydroponics vegetable garden as a food security and nutrition strategy for urban low income population. a case study from Uruguay. Social uses of simplified hydroponics by different population Practical hydroponics and greenhouses, 73. Av. online at http://www.chasque.net/frontpage/asudhi/Pagina-Ingles/Simplified%20HydroponicsRocha.PDF. Caldeyro-Stajano, M., Cajamarca, I., Erazo, J., Aucatoma, T. and Izquierdo, J. 2003. Simplified hydroponics in Ecuador. Practical hydroponics and greenhouses, 71. Available online at http://www.hydroponics.com.au/php/viewtopic.php?t=74. Caldeyro-Stajano, M. 2004. Simplified hydroponics as an appropriate technology to implement food security in urban agriculture. Practical hydroponics and greenhouses, 76. Available online at http://www.cipotato.org/urbanharvest/documents/pdf/SHAU_Foodsecurity.pdf. FAO 2008. FAO nutritional country reports on www.fao.org , last connection 01/12/08. Fontana, E., Nicola, S., Hoeberechts, J., Saglietti, D. and Piovano, G. 2004. Managing traditional and soilless culture systems to produce corn salad (Valerianella olitoria) with low nitrate content and lasting postharvest shelf-life. Acta Hort. 659:763-768. Rodríguez-Delfín, A., Chang, M. and Hoyos, M. 2001. Lettuce production in a peruvian modified dft system. Acta Hort. 554:273-278. Zanin, G., Ponchia, G. and Sambo, P. 2009. Yield and quality of vegetables grown in a floating system for ready-to-eat produce. Acta Hort. 807:433-438.
Tables Table 1. Cost of the material for the construction of a simplified hydroponic system on substrate. Growing system Wood Nails and metal wire Plastic film Polystyrene panels Pins Transport Total
#S 41,31 2,19 5,06 18,90 1,77 2,38 71,61
€ 9,67 0,51 1,18 4,42 0,42 0,56 16,76
Table 2. Running costs of 1-year cultivation of a simplified hydroponic system on substrate (excluding labour cost). 1-year cropping costs Water Analyses Seeds Substrate Fertilizers Total
#S 1,70 0,21 0,81 4,53 7,25
€ 0,40 0,05 0,19 1,06 1,70
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Table 3. Yield and gross income per year of the leafy vegetables tested in the hydroponic gardens in Trujillo. Plant density
Yield
(plants m-2) (Kg m-2) Lettuce 70 10.7±0.2 Radish 230 3.2±0.1 Leaf Beet 70 5.4±0.6 Garden Beet 70 3.6±0.2 Baby Leaf Lettuce 100 6.3±0.4
Num. of cycles Yield per year Unit Cost (cycles yr-1) 5 12 4 4 -
Figurese
Fig. 1. Installation on a simplified floating system.
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(Kg m-2 yr-1) 51.36 38.40 21.60 14.40 25.20
#S/Kg 2.3 1.2 2.0 2.0 -
Income per year #S € 118.1 27.6 46.1 10.8 43.2 10.1 28.8 6.7 -
Fig. 2. Return time of the investment for the crops adopted, excluding labour cost (r = 5%).
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