Read the full story from NPR.
Dave Chapman and dozens of other long-time organic farmers packed a meeting of the National Organic Standards Board in Jacksonville, Fla., this week. It was their last-ditch effort to strip the organic label from a tide of fluid-fed, “hydroponic” greenhouse-grown vegetables that they think represent a betrayal of true organic principles.
One of the issues raised in the NPR story is whether traditional organic farming is less resource intensive than hydroponic growing methods. Because I’m a librarian and I was curious, I did a little bit of digging and found the following articles analyzing the life cycle impacts of hydroponic and conventional agricultural growing methods.
Steven W. Van Ginkel; Thomas Igou; Yongsheng Chen (2017). “Energy, water and nutrient impacts of California-grown vegetables compared to controlled environmental agriculture systems in Atlanta, GA.” Resources, Conservation and Recycling 122, 319-325. DOI: 10.1016/j.resconrec.2017.03.003
The Central Valley in the State of California alone produces most of our nation’s fruits and vegetables and represents just 1% of the nation’s farmland. Since California’s recent drought was the worst in the last 1200 years, supply of these products may decrease and new sources are needed. To understand the efficacy of growing fruits and vegetables more locally, the energy, water and nutrient impacts of growing fruits and vegetables in local hydroponic and aquaponic controlled environment agriculture systems are compared to vegetables grown in California and shipped to Atlanta, GA. Hydroponically and aquaponically grown fruits and vegetables have areal productivities 29 and 10 times higher than CA-grown vegetables while hydroponically grown vegetables consume 30 times more energy than the CA-grown vegetables. There appears to be no difference in energy consumption between aquaponically- and CA-grown vegetables. On average, 66 and 8 times more water is used in CA-grown vegetables compared to the hydroponic and aquaponic growing techniques. Approximately double the nitrogen needed by plants is applied to CA-grown fruits and vegetables which suggests nitrogen is lost in runoff causing eutrophication downstream. There are 20, 348 and 10 times twenty times more rainfall, nutrients in domestic wastewater and vacant land needed to supply the water, nutrient and space requirements for vegetable production in Atlanta, GA.
Barbosa, G.L.; Gadelha, F.D.A.; Kublik, N.; Proctor, A.; Reichelm, L.; Weissinger, E.; Wohlleb, G.M.; Halden, R.U. (2015). “Comparison of Land, Water, and Energy Requirements of Lettuce Grown Using Hydroponic vs. Conventional Agricultural Methods.” International Journal of Environmental Research and Public Health 12, 6879-6891. DOI: 10.3390/ijerph120606879. Open access.
The land, water, and energy requirements of hydroponics were compared to those of conventional agriculture by example of lettuce production in Yuma, Arizona, USA. Data were obtained from crop budgets and governmental agricultural statistics, and contrasted with theoretical data for hydroponic lettuce production derived by using engineering equations populated with literature values. Yields of lettuce per greenhouse unit (815 m2) of 41 ± 6.1 kg/m2/y had water and energy demands of 20 ± 3.8 L/kg/y and 90,000 ± 11,000 kJ/kg/y (±standard deviation), respectively. In comparison, conventional production yielded 3.9 ± 0.21 kg/m2/y of produce, with water and energy demands of 250 ± 25 L/kg/y and 1100 ± 75 kJ/kg/y, respectively. Hydroponics offered 11 ± 1.7 times higher yields but required 82 ± 11 times more energy compared to conventionally produced lettuce. To the authors’ knowledge, this is the first quantitative comparison of conventional and hydroponic produce production by example of lettuce grown in the southwestern United States. It identified energy availability as a major factor in assessing the sustainability of hydroponics, and it points to water-scarce settings offering an abundance of renewable energy (e.g., from solar, geothermal, or wind power) as particularly attractive regions for hydroponic agriculture. View Full-Text
The following review article includes a discussion of hydroponic vs conventional growing methods in the context of urban agriculture.
Benjamin Goldstein, Michael Hauschild, John Fernández, Morten Birkved (2016). “Urban versus conventional agriculture, taxonomy of resource profiles: a review.” Agronomy for Sustainable Development, 36 (1), article 9. DOI: 10.1007/s13593-015-0348-4.
Urban agriculture appears to be a means to combat the environmental pressure of increasing urbanization and food demand. However, there is hitherto limited knowledge of the efficiency and scaling up of practices of urban farming. Here, we review the claims on urban agriculture’s comparative performance relative to conventional food production. Our main findings are as follows: (1) benefits, such as reduced embodied greenhouse gases, urban heat island reduction, and storm water mitigation, have strong support in current literature. (2) Other benefits such as food waste minimization and ecological footprint reduction require further exploration. (3) Urban agriculture benefits to both food supply chains and urban ecosystems vary considerably with system type. To facilitate the comparison of urban agriculture systems we propose a classification based on (1) conditioning of the growing space and (2) the level of integration with buildings. Lastly, we compare the predicted environmental performance of the four main types of urban agriculture that arise through the application of the taxonomy. The findings show how taxonomy can aid future research on the intersection of urban food production and the larger material and energy regimes of cities (the “urban metabolism”).