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International Malaysia-Indonesia-Thailand SIC, Vol 2 (2017), 1-4 Symposium on Innovation and Creativity (iMIT-SIC), Vol 2 (2017) pp 1- 4 e-ISBN: 978967xxxxxxx

NEW EMERGING HYDROPONIC SYSTEM Y.N. Chow1, L.K. Lee2, N.A. Zakaria1, K.Y. Foo1* 1

River Engineering and Urban Drainage Research Centre (REDAC), Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Penang, Malaysia. 2 School of Industrial Technology, Universiti Sains Malaysia, 11800 Gelugor, Penang, Malaysia.

Email: [email protected] (K.Y. Foo)

Abstract: Today, controlled environment agriculture, notably greenhouse food crops production has emerged to be the most intense forms of agricultural enterprises to overcome the multidimensional manifestations of climate change, fresh water scarcity, and pressing need of the growing food demand. Hydroponic culture, a soilless cultivation technology with the application of nutrient medium, has become the fastest growing and second generation of crop production system in agricultural industry. These hydroponic systems are enclosed in greenhouse-type structures to provide temperature control, reduce evaporative water loss, preventive control of disease and pest infections, and protection against the changing weather. In this work, the application of nutrient film technique for selected food crop models cultivation under controlled environment, for the investigation of different toxic heavy metal pollutants on the food crops quality and yield has been attempted. The physical growth of food crops has been elucidated, in relation to the seed germination, and elongation of roots and shoots. The physiological alterations of photosynthesis pigment content, proline accumulation, lipid peroxidation, and enzymatic antioxidants in food crops were evaluated. Results showed that the roots and shoots length were significantly retarded parallel with the concentration of water pollutants and duration of exposure. These metal ions induced lipid peroxidation, disruption of chlorophylls, and stimulate the accumulation of proline and alterations of antioxidant enzymes: catalase, guaiacol peroxidase, and ascorbate peroxidase. These findings justified the feasibility of hydroponic cultivation technique, and the possible impacts of wastewater reuse irrigation practice on food crops. This project could be a preliminary step for the development of hydroponic agricultural system, an emerging concept in the future urban agriculture planning. This current research would contribute to the nation and scientific communities, in terms of potential reuse of treated wastewater for food crops production, governance of national water and land footprint, substantial reduction in the excessive application of agrochemicals, and potential improvement of the quality of food crops and environmental sustainability. Keywords: Agriculture, Food-water nexus, Hydroponic, Phytotoxicity, Wastewater irrigation

INTRODUCTION Today, the agenda of food security has prevailed to be a global concern, with the speculation that the world food production would need to increase by 70 % in the next 40 years to meet with the demand from the population of exceeding 9.1 billion by 2050 (FAO, 2009). In parallel to the urbanization and new city development, urban cultivation system, also known as hydroponic system, is now seen as a viable solution to the limited land area suitable for agriculture, and a more rational use of water resources, to provide better opportunities for a sustainable food supply in both developed and developing countries (Besthorn, 2014; Podmirseg, 2013). Hydroponic system is a new cultivation technology that applies nutrient solutions without the soil substrates, but with the presence of artificial supporting medium

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(Bhattarai et al., 2008). It offers the ability to reuse water and nutrients, ease of environmental variability control, higher production yield, and successive prevention of soil-borne diseases and pests (Lommen, 2007; Molitor, 1990) (Table 1). The evolution has been more prominent, with the novel development of vertical agricultural structures, that has attracted supporting attention from different global regions, South Korea, China, Japan, Singapore, Italy, Holland, United Kingdom, Jordan, Saudi Arabia, United Arab Emirates and Canada which are moving ahead towards vertical farming projects (Besthorn, 2014). Accordingly, there are approximately 20 million hectares of lands irrigated with untreated, partly treated, diluted or treated wastewater, with China, Mexico, India, Chile and Pakistan recorded the highest intensity of untreated and treated wastewater use. In Pakistan, about 26 % of national vegetable production is irrigated with wastewater while in Hanoi, 80 % of vegetable production from urban and peri-urban areas is irrigated with diluted wastewater. Across the major cities of West Africa, between 50 and 90 % of vegetables consumed by urban dwellers are produced within or close to the city, which much of the water used for irrigation is polluted. It was estimated that 700 million consumers depend on the vegetables grown in untreated or partially treated wastewater, and the health risks for those involved in the production chains are questionable (Hamilton et al., 2007; Jiménez and Asano, 2008; Keraita et al., 2008). These scientific evidence has quantified the aggregate contribution of wastewater to food supply. These available wastewaters may contain nutrients that favour the crop growth, but could possibly exceed the physiological demand to administer toxic effects, and might be subjected to bioaccumulative impacts throughout the food chains. Literature researches have reported the mutagenic, teratogenic, neurotoxic and carcinogenic effects, even at a trace concentrations in the human body. Agriculture remains an important sector in Malaysia, contributing 9.3 % to the national GDP in 2014, with 97 % of the irrigation water derived from the polluted rivers. However, a valid food or irrigation policy for the effective control of wastewater irrigation have not been established. The objectives of this fundamental research are to (1) assess the feasibility of hydroponic system for food crops cultivation; (2) examine toxic pollutants uptake of plants grown from polluted irrigation water, (3) evaluate the effects of wastewater reuse in irrigation on growth and yield of food crops, (4) investigate the health risks associated with the bioaccumulation of pollutants in food cropsand (5) establish a pollutant transfer model predicting the translocation of toxic substances from the contaminated wastewater, by the application of hydroponic techniques.

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Table 1. Advantages and limitation of hydroponic systems in comparison to soil-based culture. Issues Water

Hydroponic system - Efficient water usage - Irrigation water can be recycled or reused - No nutrient waste due to water runoff - Irrigation water is supplied directly to root areas - Possibility of controllingwater holding ability by using different kinds of medium Land usage - Less affected by soil and and effect of external factors environment - İndoor system and ease of nutrient control - Excellent control of environment temperature, humidity and lighting time Fertilizers - Even distribution and nutrient - Efficient use of fertilizers and solution cost saving - Ease of pH control Quantity and quality of crop

- Stable and even amount of crop production

Soil culture - Insufficient water usage - Irrigation water cannot be recycled or reused - Eutrophicastion of the environment due to surface run-off - Difficulties of the control of water-holding capacity

References Midmore and Deng-lin (1989)

- Limited by different soil types - Subjected to the changing external environment

Gibeaut et al. (1997); Jones (1997); Norén et al. (2004); Norstrӧm et al. (2004)

- Uneven distribution - Excessive use of fertilizers - Variation of pH with the changing weather and external factors - Unstable crop production, and subjected to pests/soilborne pathogens

Rolot (1999); Resh (2013)

Cornish (1992); Sarooshi and Cresswell (1994); Rolot (1999); Resh (2012)

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METHODOLOGY The food crops cultivation will be conducted by hydroponic technique in the greenhouse, using bean and vegetation as the model plants. A summary of the proposed assessments are depicted in Figure 1.

Figure 1. Flow chart of methodology

FINDINGS Table 2. Effects of heavy metal pollutants on food crops models in relation to physical and physiological properties. Analyses Physical growth Seed germination Root and shoot elongation Physiological processes Total chlorophyll, chlorophyll-a, chlorophyll-b, carotenoid Lipid peroxidation Proline Guaiacol peroxidase, POD; ascorbate peroxidase, APX; catalase, CAT Bioaccumulation of metals ions Metal uptake and translocation

Findings Reduced seed germination rate Impaired physical growth Diminished photosynthesis pigments levels Induced lipid peroxidation Accumulation of proline content Altered antioxidant enzymes activities

Accumulation of metals ions and distributed to aboveground plant parts

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CONCLUSIONS The current research findings have verified the feasibility of the newly adopted hydroponic systems under controlled environment for food crops cultivation. The effects of heavy metals contaminated irrigation water have been shown to reduce plants physical growth, disrupt the photosynthetic pigments synthesis, oxidation on the membraneous lipid molecules, and accumulation of proline as the metal scavenger and osmoregulator, and alterations in antioxidant enzymes activities. This study could contribute to the country and Malaysian populace by proposing the water quality guidelines for the safe use of wastewater in agriculture irrigation. Eventually, this could help in integrating water reuse into the core water governance frameworks and concurrently reduces the water footprint of food production in Malaysia. The proposed research project also presents a blueprint for food safety policies for the protection of human health. The concept of hydroponic cultivation systems could be integrated into the vertical farming, to support the sustainability of food-water security, land usage, and publich health.

REFERENCES Besthorn, Fred H. "Vertical farming: Social work and sustainable urban agriculture in an age of global food crises." Australian Social Work 66, no. 2 (2013): 187-203. Bhattarai, Surya Prasad, Clemence Salvaudon, and David J. Midmore. "Oxygation of the rockwool substrate for hydroponics." Aquaponics Journal, no. 49 (2008): pp. 29-33. Cornish, Peter S. "Use of high electrical conductivity of nutrient solution to improve the quality of salad tomatoes (Lycopersicon esculentum) grown in hydroponic culture." Australian Journal of Experimental Agriculture 32, no. 4 (1992): 513-520. Daniel, Podmirseg. "Contribution of vertical farms to increase the overall energy efficiency of urban agglomerations." Journal of Power and Energy Engineering 2, no. 04 (2014): 82. Food and Agricultural Organisation, 2009. 50.pdf Gibeaut, David M., John, Hulett, Grant, R. Cramer, and Jeffrey, R. Seemann. "Maximal biomass of Arabidopsis thaliana using a simple, low-maintenance hydroponic method and favorable environmental conditions." Plant Physiology 115, no. 2 (1997): 317. Hamilton, Andrew J., Frank Stagnitti, Xianzhe Xiong, Simone L. Kreidl, Kurt K. Benke, and Peta Maher. "Wastewater irrigation: the state of play." Vadose zone journal 6, no. 4 (2007): 823-840. Jiménez, Blanca, and Takashi, Asano, eds. Water reuse: an international survey of current practice, issues and needs. London: IWA, 2008. Jones, J. Benton, 1997. Hydroponics: A Practical Guide for the Soilless Grower. St. LuciePress, Boca Raton, Fla. Keraita, Bernard, Blanca Jiménez, and Pay Drechsel. "Extent and implications of agricultural reuse of untreated, partly treated and diluted wastewater in developing countries." CAB reviews: Perspectives in agriculture, veterinary science, nutrition and natural resources 3, no. 58 (2008): 1-15. Lommen, Willemien JM. "The canon of potato science: 27. Hydroponics." Potato Research 50, no. 3 (2007): 315-318. Midmore, David, and Wu Deng-Lin. "Work that water! Hydroponics made easy." Waterlines 17, no. 4 (1999): 28-30. Molitor, Hans. "The European perspective with emphasis on subirrigation and recirculation of water and nutrients." In Symposium on Bedding and Pot Plant Culture 272, pp. 165-174. 1989. Norén, Hanna, Per Svensson, and Bertil Andersson. "A convenient and versatile hydroponic cultivation system for Arabidopsis thaliana." Physiologia Plantarum 121, no. 3 (2004): 343-348.

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Norström, Anna, Karin Larsdotter, and Gunnel Dalhammar. "Theoretical energy requirements for maintenance of green plants in hydroponic wastewater treatment." Vatten 3 (2004): 187-191. Resh, Howard M. “Hydroponic Food Production: a Definitive Guidebook for theAdvanced Home Gardener and the Commercial Hydroponic Grower.” (CRC Press, Boca Raton, Fla, 2013). Rolot, Jean Louis, and Hugues Seutin. "Soilless production of potato minitubers using a hydroponic technique." Potato Research 42, no. 3 (1999): 457-469. Sarooshi, Ruhi A., and Cresswell Geoff C. "Effects of hydroponic solution composition, electrical conductivity and plant spacing on yield and quality of strawberries." Australian Journal of Experimental Agriculture 34, no. 4 (1994): 529-535.