Literature Review Carter McKinnon 1 Hydroponics as an alternative food production method Abstract: Current food movements in the United States seek local implementation of alternative food production methods as means of increasing the food security of a community, reducing food miles, and avoiding industrial food. Hydroponics is a popular breed of alternative system because it has the potential to be very sustainable. However, as I discovered, hydroponics and other urban food production methods are not inherently positive; careful management is required to fulfill the goal of besting industrial production methods and realizing the potential benefits of restructured food systems. Researchers should continue to pursue new technologies to optimize hydroponic methodology, but we should keep in mind the large array of factors that determine economic and environmental outcome in psuedonatural systems. Below I present the literature s consensus on two common topics: the yield of a hydroponic system, and the nutritional value of the product; and the theme of using hydroponics as an added profit (whether monetary or carbon-offsetting) to an existing system. I then present two important critiques of hydroponics and alternative systems in general: the ultimate sustainability of hydroponic systems, and the current disjoint relationship of hydroponics and organic food. Biomass yield and nutrition Because hydroponic growing methods utilize water as the medium instead of soil, the systems garner feeble public support: there is little acceptance of soil-less growing techniques in society and people are critical of their use. This applies to the production method itself as well as to the products. Many consumers prefer naturally produced food (De Wilt and Dobbelaar 2005) and refuse to buy products grown using hydroponic techniques (Specht, Siebert, and Hartmann 45). Despite the public reluctance, there is a considerable body of work that demonstrates the nutrient equivalence of hydroponic vegetables and soil-grown vegetables, and in many cases hydroponic systems were able to achieve higher yields than their soil counterparts. The Countryside & Small Stock Journal encourages livestock farmers to consider hydroponic growing of fodder, because of the fast potential savings and small-scale required: farmers will reap higher yields and save considerably on feed and energy costs Because hydroponic systems do not require large foot-prints, a field s worth of food can be produced in a building, barn, greenhouse, or basement (Anonymous 79).
Literature Review Carter McKinnon 2 In this case, sprouting seed in a hydroponic system for one week increased the protein content of the biomass by 50%; and hydroponic fodder is 80% digestible, compared to dry hay s 30% digestibility. Nutrient content has also been shown to be equivalent among hydroponic fertilizers (Savidov 20), with some plants achieving very high Brix 1 ratings (Shinohara, Aoyama, and Fujiwara 197). Adding value or purpose A common theme in hydroponic farming is its ability to thrive in symbiotic relationships with the production of other commodities, or the reuse/purification of waste. The added value of any biomass production makes these systems alluring to a myriad of industries. I found the following two examples to be the most thoughtprovoking. Aquaponics, a hydroponic technique utilizing fish effluent as a nutrient source in a continual circulating system was proven to be very effective by a team in Alberta, Canada, a region with large existing fish-producers. The team concluded that Crop production can reach higher levels in aquaponics compared to the average production in the industry based on conventional hydroponics technology, and, The rate of fish biomass production in aquaponics is comparable with conventional aquaculture operation (Savidov 20). This operation is inherently diversified because of fish and plant production, and neither product showed any disadvantages being a part of this type of system. This shows that hydroponics can add great value, and great carbon reductions to fish farming. Hydroponic growing also shows great promise as a means of water purification. Following the trend of wetlands as purifiers for wastewater in rural areas, researchers tested the idea of using hydroponic plant systems as a means of purification for urban areas. The results were hugely positive: The NFT system with wooly digitalis and foxglove significantly reduced the total organic load the process with plants was very effective in reducing SS 2, BOD 3, and COD 4 parameters. After 24 h the system reached the legal discharge levels (Vaillant, Monnet, and Sallanon 698). Though not all plants can survive on wastewater, there are many that can. Choosing species like foxglove (like this study did) can make the high initial cost of installation acceptable in the long run, because the resulting biomass can be sold as a 1 2 3 4 a measure of the nutrient density of vegetation, usually edible plants. suspended solids biochemical oxygen demand chemical oxygen demand
Literature Review Carter McKinnon 3 commodity or as compost. The two above cases represent a movement of adding hydroponic techniques to systems that inherently encourage their use to be sustainable as added profit. Sustainability A review of ZFarming 5 literature, including hydroponic farming, concluded the following on the sustainability of the practice: managing ZFarming is not unproblematic. For some of the envisaged applications, the technical solutions to recycling water, energy, and waste are known but need to be developed further we found further weaknesses [such as] the tendency of food activists and researchers to assume something inherent about the local scale (Specht, Siebert, and Hartmann 42). This study reviewed alternative methods of urban food production critically, and found that while these methods have great potential, the novelty of the techniques makes their continued used uncertain, and the real picture of their environmental impact is still ambiguous. However, the overwhelming opinion of the material I have read is that hydroponics offers the greatest potential benefit of any known food production method. By recycling waste and water, decreasing food miles, and using less energy in general, hydroponic growing is worth our time and money. Put simply in the Countryside & Small Stock Journal: [hydroponic systems have] no need for pesticides or herbicides, high yields in a limited space, and up to 90% less water required compared to soil production (Anonymous 79). No other technique that has shown commercial promise offers this feature set. Nutrient source concerns Hydroponics is considered a saving grace invention by food researchers/authors, somewhat ironically, because the technique almost never results in organic products. In order to maintain yields, industrial fertilizers are added habitually. And the challenge of organic growing with hydroponics is a struggle shared by a growing number of producers. The aquaponics study in Alberta found a supply of, organically certified minerals. Rock potassium sulfate containing up to 50% K2O and soluble kelp powder can be used as adequate organically certified potassium supplements. The aquaponics project offered a new opportunity to develop a whole new industry based on supplies for organic hydroponics. (Savidov 19) While this sound encouraging, hydroponic systems need more than minerals they need fertilizer (mainly, nitrogen). However, the direct use of organic fertilizer proved to be deleterious to plant growth. Therefore, organic fertilizer has been microbially pre- 5 zero acreage farming
Literature Review Carter McKinnon 4 processed before incorporation into hydroponic solutions (Shinohara, Aoyama, and Fujiwara 190). When the fertilizers are pre-processed, only 30% of its nitrogen is converted into nitrate, a necessary nutrient in hydroponic systems (Shinohara, Aoyama, and Fujiwara 192). The team studied the addition of microbial cultures directly to a hydroponic solution to test the direct addition of modern organic fertilizers (to avoid the step of pre-processing.) Even after testing 4 different culture sources (including sea water and compost), they concluded that The culture solution of microorganisms could be used as the hydroponic solution in our organic hydroponics system. The yield and quality of butterhead lettuce and tomato fruits were not significantly different from those in the conventional hydroponics system. Our method, which adds organic fertilizer directly into the hydroponic solution during cultivation, is convenient and practical. (Shinohara, Aoyama, and Fujiwara 202). Despite the current mixed-bag of methods, there is a considerable issue on the horizon if we choose to adapt hydroponic methods on a large scale. The demand for organic food is only getting louder. However, promising results have emerged from novel techniques, and organic hydroponics could be just around the corner. Conclusions Hydroponics is a pseudonatural way to produce food meaning it emulates some of nature s processes/components to grow vegetation without the need for soil or the outdoors; the benefits of which are numerous. The produce coming off of the nutrient film has been shown to be nutritionally equal to its soil-grown counterparts, and can produce yields relative to cost similar to conventional agriculture if not greater. Because hydroponics is principally alternative, it is common practice to choose alternative nutrient sources, often waste, in hydroponic systems, to utilize plant production as added profit. These characteristics describe hydroponics very positively, but under the surface, there are countless factors that decide the ultimate sustainability and environmental impact of alternative growing systems. Similarly, because hydroponic produce is rarely organic, the widespread use of the practice seems contradictory to larger goals of current food movements. When developing an alternative food network in an area, methods such as hydroponics seen as scientific and modern should not be chosen because of their sex appeal, because the ultimate impact of the system could be contrary to the goals of the user.
Literature Review Carter McKinnon 5 Works Cited Anonymous. "Fresh, Healthy Livestock Feed Everyday with Hydroponic Fodder Systems." Countryside & Small Stock Journal 97.2 (2013): n. pag. Print. Savidov, Nick. Evaluation and Development of Aquaponics Production and Product Market Capabilities in Alberta. Alberta: Crop Diversification Centre South, Alberta Agriculture, Food and Rural Development, 2004. Print. Shinohara, Makoto, Chihiro Aoyama, and Kazuki Fujiwara. "Microbial Mineralization of Organic Nitrogen into Nitrate to Allow the Use of Organic Fertilizer in Hydroponics." Soil Science and Plant Nutrition 57.2 (2011): 190-203. Print. Specht, Kathrin, Rosemarie Siebert, and Ina Hartmann. "Urban Agriculture of the Future: An Overview of Sustainability Aspects of Food Production in and on Buildings." Agriculture and Human Values 31.1 (2014): 33-51. Print. Vaillant, Nathalie, Fabien Monnet, and Huguette Sallanon. "Use of Commercial Plant Species in a Hydroponic System to Treat Domestic Wastewaters." Journal of Environmental Quality 33.2 (2004): 695-702. Print.