In This Issue
Summer Bridge on Smart Agriculture
June 15, 2022 Volume 52 Issue 2
People everywhere rely on agriculture in one form or another – for food, animal feed, fiber, and other necessities. The summer 2022 articles describe precision indoor farming and alternative protein food systems, advances in food processing, genome editing, digitalization, sustainable and regenerative agriculture, the role of a circular economy, and the important role of policy.

Precision Indoor Farming and Alternative Protein Food Systems

Tuesday, June 14, 2022

Author: K.C. Ting, Michael B. Timmons, and Ricardo San Martin

Research and new technologies are needed to develop precision plant growth and other systems alternatives for food production.

Food and agriculture systems (FASs) are physical and conceptual models of people’s use of natural and human-made resources to produce food, feed, fiber, fuel, and furnishing. It has become increasingly important for FASs to be socially, economically, and environmentally sustainable.

Continuous modernization of FASs takes advantage of scientific and engineering advances to ensure both quantity and quality of products and services. FAS development has particularly benefited from advances in the following areas: machine intelligence enabled by automated perception, reasoning/learning, communication, and task planning/execution; biological science, biotechnology, and bioprocessing; understanding, control, and management of environmental factors; and engineering of systems informatics and analytics.

Two rapidly evolving forms of high-tech food and agricultural production systems are worthy of attention: the precision indoor farming system (PIFS) and alternative protein food system (APFS). PIFS, mostly used for plant and/or aquaculture production, is arguably the most technology-intensive form of agriculture. APFS offers solutions to the challenges inherent in large-scale meat production.

Precision Indoor Farming Systems

A precision indoor farming system comprises numerous interrelated components, from the plants and animals to the enclosing structure(s), growing facility, equipment, environmental and operational control apparatus, information gathering and processing devices, and labor and management practices. PIFSs have evolved from production under simple, modified environments to precise, controlled environments. We focus on their application in plant and aquaculture systems.

Controlled Environment Plant Systems

The most advanced form of controlled environment plant system (CEPS)—also known as a vertical farm, plant factory, and phytomation (Ting et al. 2021)—falls within the concept of PIFS. The ability to optimally integrate indoor and outdoor environments, plant culture, human workers, machines, social acceptance, market demand, and economic viability is essential to a successful advanced CEPS (Gómez et al. 2019; -Shamshiri et al. 2018; Ting et al. 2016). Figure 1 shows various forms of the CEPS.

Ting figure 1.gif
FIGURE 1 Forms of plant production ranging from open-field farming to precision indoor farming systems. Adapted with permission from Ting et al. (2021); photos courtesy of Guoqiang Ren.

Advanced Greenhouses and Urban Farms

Basic greenhouses provide modified and protected environments for crop production under cover. Past and future improvements emphasize measures such as recycling glazing materials, minimizing discarded waste and chemicals, maximizing usable products, using waste energy, and adopting consumer-centered production planning.

Notable differences between advanced and basic greenhouses are stronger and larger outer structures, computer control of production environments, innovative crop growing systems with various soilless forms, AI-supported operations, and sophisticated mechanization/automation for task planning and execution. Advanced greenhouses allow maximization of nutrient use for crop growth and reduced distance between crop production facilities and markets.

Urban farms and other food systems have been promoted as an important component of new urban infrastructure. Technology needs for their support include system of systems (SoS) engineering solutions for plant production, environmental controls, materials handling, process control, and decision support. With these features these innovative food production systems may enhance social, economic, and surrounding environmental conditions in urban centers (Despommier 2010; Nelkin and Caplow 2008).


In addition to being well suited for integration in urban farming systems in “smart cities,” the CEPS shares the concept of advanced manufacturing facilities and is capable of producing plant-based materials for food as well as pharmaceutical and chemical feedstocks. And it is particularly useful in areas where conditions are not conducive to conventional crop production.

A CEPS can readily implement the most modern automation, crop culture, environmental control, and systems integration methods and technologies (Ting 2013). Their high degree of closure allows not only the use of sun-independent light (i.e., sources completely powered by electricity) to provide precise quantity and quality of photons to plants but also the application of advances in artificial intelligence.

In terms of sustainability, CEPSs may facilitate the breeding of seeds to maximize crop productivity and meet production targets, the use of green building principles in facility design, autonomous capabilities including robotics, marketing strategies that respond to customer interests, and just-in-time operations that minimize inventory (van Delden et al. 2021).

For all these reasons, the CEPS is an ideal form of agriculture that will both benefit significantly from and promote the convergence of science, engineering, and technology to transform FAS (Benke and Tomkins 2018; Kozai 2018; Kozai et al. 2016). To ensure its effectiveness, it would be beneficial to create a comprehensive, concurrent analysis cyber platform, using an SoS approach, to enable solution-based decision support for collaborations among cross-disciplinary experts and multisector stakeholders.

Controlled Environment Aquaculture and Aquaponics Systems

The production of fresh and saltwater seafood in a precision indoor farming system is done in recirculating aquaculture systems (RASs), which discharge less than 50 percent of their standing water volume to the environment (river, lake, or ocean) per day (Timmons et al. 2018, p. 769).[1] Their normal hydraulic retention times (15–45 minutes) and fish tank geometric designs are similar to those of a flow-through system, but in a RAS most (>95 percent) of the discharge water from the fish tanks is returned to the tanks after treatment to remove ammonia, settlable solids, and carbon dioxide and to restore oxygen and other water quality parameters. 

Advanced greenhouses offer computer control
of the environment, soilless crop growing systems, and automation of task planning and execution.

A deterrent to widespread RAS adoption is cost: for yearly production capacity it exceeds $15 per kg for a salmonid species, compared to net pen systems ($3–$5). RAS production costs are higher because of the energy consumed to pump water in the recirculating process (10 kWh per kg of fish produced). Systems have been designed and built to require less than 50 percent of the energy used by traditional RAS, thanks to mixed cell raceway technology (Timmons et al. 2018, pp. 122–28) and low-head pumps (Ledford 2021) that move 11,000 lpm per kW of power input (figure 2). Production systems designed as a combination of RAS and outdoor bioflock systems can be the most cost-effective.

Consumer Concerns

Consumer concerns that farmed fish tend to have lower levels of beneficial omega-3 fatty acids than wild fish (WRI 2019, chapter 23) are valid. But the old adage that “we are what we eat” holds true for farmed fish: if a RAS fish is fed a diet nutritionally similar to that of a pig or chicken, it will have a similar polyunsaturated fatty acid (PUFA) profile. The beauty of a RAS-produced fish is that any PUFA profile can be created—such as one with a high ratio of omega-3 to -6 that is beneficial to human heart health. But the costs associated with creating PUFA profiles may deter consumers unwilling to pay higher prices for such seafood.

Ting et al figure 2.gif

Consumers also raise concerns about the wellbeing of RAS-raised fish, citing animal welfare and the use of antibiotics—high rearing densities can cause fish stress, and disease may result from poor water quality (Scott 2021). In all fish systems, control of the vectors that introduce disease is essential to minimize outbreaks. A RAS facilitates control of the two most important vectors, the water and the fish. Placing all new animals in quarantine to ensure that no diseases are present is critical to prevent outbreaks in any farm setting and particularly for a RAS.


RAS-cultured fish coupled to a hydroponic vegetable system—a combination called aquaponics—is probably the most sustainable method of food production available. Generally, fish capture 50 percent or less of the macro- and micronutrients ingested (Timmons et al. 2018, p. 200). In aquaponic systems, hydroponic plants, through their root structures, receive all their required nutrients from the nonassimilated nutrients generated from the RAS. Comparisons of hydroponics (based on inorganic nutrients) and aquaponics (natural organic nutrients supplied by the fish) demonstrate the viability of aquaponics (Anderson et al. 2017; Rodgers et al. 2021; Timmons et al. 2018, chapter 19).

Alternative Protein Food Research

Growing global consumption of animal-based products, particularly red meat, significantly contributes to greenhouse gas emissions and poses tremendous burdens on the resource-intensive and complex systems of raising and slaughtering animals. Alternative protein food systems promise to remedy these issues, though significant challenges must first be overcome, as described below.

Three routes for the development of APFS are being explored: production of animal cells via fermentation (“cultured” or “cultivated” meat), use of plant components (e.g., proteins, fats) to produce plant-based foods (PBF), and precision fermentation. Each has advantages and challenges.

Cultured Meat

Cultivated meat is edible animal tissues or cells produced in a controlled environment, bypassing the body of the animal in favor of direct, additive construction from genes. The process results in a food product that is similar or equivalent to conventional meat products in sensory and nutritional character.

Producers of cultivated meat are motivated by several factors:

  • climate change and the need to develop alternative food production systems that result in familiar consumer goods,
  • reduction in the resources used and animals needed to feed a growing global population, and
  • innovation to help meet the expected doubling of meat demand by the year 2050, absent any significant intervention in human diet preferences.

Although it is possible to grow mammalian, avian, fish, or crustacean cells in small bioreactors for demonstration purposes, both fermentation theory and industry experience indicate that this approach may not yield economically viable whole-animal replacements because of limitations inherent to the growth of mammalian cells: low cell numbers (e.g., 2 × 107 cells/ml), high capital equipment costs to contain contamination, and expensive media.

Furthermore, analysis shows that metabolic enhancements, different bioreactor configurations, or cheap media derived from plant hydrolysates are not enough to yield cost-competitive products (Humbird 2021). This probably explains why some companies are shifting to the production of animal cells as ingredients (e.g., lipid cells) to enhance the organoleptic properties (e.g., taste, smell, mouthfeel) of PBF. A major research effort led by Tufts University may help improve the economics of this approach (Nicholas and Silver 2021).

A further complicating factor is that cultivated meat products, unlike other products discussed here, are subject to a distinct US regulatory paradigm based on a risk assessment process that did not exist before 2018. In contrast, plant-based products have well-established regulatory systems that allow a more direct pathway to market than cultivated meats.

Plant-based Foods

In recent years several companies have shown that plant-based ingredients can be processed to mimic ground beef burgers in both taste and texture (e.g., Impossible Foods). Expanding the range of products to other categories—such as whole-cut meat, fish, cheese, eggs, and yogurt—requires sophisticated research based on a deep understanding of the scientific principles involved in creating such foods and knowledge of protein, lipid, and carbohydrate chemistry, micro-structure, rheology, emulsification, and cooking behavior (McClements and Grossmann 2021).

The necessary expertise is mostly proprietary in companies, with little sharing of open-source knowledge. Major US universities with food science programs, such as the University of California, Davis, and Cornell, are not yet fully active in this space. Fortunately, this is rapidly changing with the work led by Julian McClements at the University of -Massachusetts at Amherst and Atze Jan van der Goot at Wageningen -University in Holland.

Precision Fermentation

This newer approach consists of expressing unique animal proteins, fats, or pigments into microorganisms grown in fermenters—for example, for replacement of palm oil (Karamerou et al. 2021) and casein (Hettinga and Bijl 2022). Because fermentation is expensive, it is not expected that this technology will yield bulk food ingredients but rather functional ingredients to be used in combination with cheaper plant-based matrices.

Besides cost, important hurdles include the need to obtain proteins with the right functionalities, such as susceptibility to posttranslational modifications.

Challenges to Alternative Protein Food Production

As detailed above, APFS production at scale is limited to PBF, particularly ground meat analogs. Despite media attention, the penetration rates of meat analog products remain low (Van Loo et al. 2020) and USDA data indicate that overall meat consumption has not declined with the introduction of alternatives.[2]

Production of animal cells as ingredients may enhance the organoleptic properties 
(e.g., taste, smell, mouthfeel) of plant-based foods.

Besides customer adoption, the plant-based food industry must address important production challenges to achieve greater impact:

Limited number of protein sources: At present, the industry uses a handful of proteins (e.g., soy, pea, and wheat gluten) available at scale. However, these proteins lack the functionality to produce important products such as eggs, yogurts, or cheese. Significant research is needed to obtain novel sources at scale with the right functionalities. Proteins from algae and green leaves (e.g., rubisco) show good functionalities, but their very low extraction yields result in high-cost proteins (Tamayo Tenorio et al. 2018).[3]

  • Limited range of plant lipids: The plant-based industry relies heavily on the few plant lipids that have high melting points, such as coconut fat, which is sourced mainly from the Philippines and Indonesia (Pham 2016). Lipid replacements must be developed for more sustainable products and the supply chain must be strengthened.
  • Standardization of plant ingredients: Extraction and purification methods affect ingredient -functionality and organoleptic properties. There is an urgent need to standardize plant ingredients from different -origins.
  • More efficient processing technologies: The current approach to produce plant ingredients is to deconstruct grains such as soy to produce protein-rich fractions. This generates significant waste that is used as animal feed. Newer technologies must be developed to incorporate less refined fractions into PBF (van der Goot et al. 2016).
  • Sustainability and health claims: The industry and -mission-oriented organizations have crafted a strong narrative (normally through non-peer-reviewed white papers) about the health and sustainability advan-tages of PBF. External, nonbiased peer-reviewed research must verify these claims and the research methods employed, and the FDA and USDA should take an active role to verify the validity of health claims/impacts.
  • Novel production technologies: Most plant-based -products rely on extrusion to reconfigure the protein fractions. This is an expensive and complex process that works with only a very limited range of raw materials. Technologies for developing highly structured foods, like steak or fish, still need major research efforts.

Concluding Remarks

Creating a sustainable world with no hunger is a major challenge. Food systems of systems are economic engines that are locally operated and globally connected. PIFS is evolving toward intelligence-driven and empowered agricultural systems by implementing human-supervised cyberphysical systems that combine human management, computational power, and physical operations.

APFS is unquestionably a good option to reduce dependency on animal-based products. Plant-based APFS is more feasible, but still needs substantial research to deliver a variety of products acceptable to consumers in taste, texture, and price.

The challenge is to design food and agriculture systems that are economically viable in today’s world -markets. The convergence of physical, chemical, biological, and social sciences in the SoS value chain is required. Product differentiation (e.g., in terms of quality, source, traceability, and social, economic, and environmental factors) may support premium pricing, but the premium is generally only about 10 percent more than the price for a competing nondifferentiated product.

For the near term, production systems need to make incremental changes toward environmental sustainability to remain economically competitive. Societal needs, however, may require transition at an accelerated pace.


Anderson TS, de Villiers D, Timmons MB. 2017. Growth and tissue elemental composition response of Butterhead -lettuce (Lactuca sativa, cv. Flandria) to hydroponic and aquaponic conditions. Horticulturae 3:43.

Benke K, Tomkins B. 2018. Future food-production systems: Vertical farming and controlled environment agriculture. Sustainability: Science, Practice and Policy 13(1):13–26.

Despommier DD. 2010. The Vertical Farm: Feeding the World in the 21st Century. New York: St. Martin’s Press.

Gómez C, Currey CJ, Dickson RW, Kim HJ, Hernández R, Sabeh NC, Raudales RE, Brumfield RG, Laury-Shaw A, Wilke AK, and 2 others. 2019. Controlled environment food production for urban agriculture. Hortscience 54(9):1448–58.

Hettinga K, Bijl E. 2022. Can recombinant milk proteins replace those produced by animals? Current Opinion in Biotechnology 75:1–6.

Humbird D. 2021. Scale-up economics for cultured meat. Biotechnology and Bioengineering 118:3239–50.

Karamerou EE, Parsons S, McManus MC, Chuck CJ. 2021. Using techno-economic modelling to determine the minimum cost possible for a microbial palm oil substitute. Biotechnology and Biofuels 14(1):57.

Kozai T, ed. 2018. Smart Plant Factory: The Next Generation Indoor Vertical Farms. Singapore: Springer.

Kozai T, Fujiwara K, Runkle ES, eds. 2016. LED Lighting for Urban Agriculture. Singapore: Springer.

Ledford GA. 2021. Peller blade with a flap. US Patent 10882593.

McClements DJ, Grossmann L. 2021. The science of plant-based foods: Constructing next-generation meat, fish, milk, and egg analogs. Comprehensive Reviews in Food Science and Food Safety 20:4049–100.

Nelkin J, Caplow T. 2008. Sustainable controlled environment agriculture for urban areas. Acta Horticulturae 801:449–56.

Nicholas I, Silver M. 2021. Tufts receives $10 million grant to help develop cultivated meat. TuftsNow, Oct 15.

Pham LJ. 2016. Coconut (Cocos nucifera). In: Industrial Oil Crops, eds McKeon TA, Hayes DG, Hildebrand DF, -Weselake RJ. Urbana IL: AOCS Press.

Rodgers D, Won E, Timmons MB, Mattson N. 2021. Complementary nutrients in decoupled aquaponics enhance basil performance. Horticulturae 8(2):111.

Shamshiri R, Kalantari F, Ting KC, Thorp KR, Hameed IA, Weltzien C, Ahmad, Shad ZM. 2018. Advances in greenhouse automation and controlled environment agriculture: A transition to plant factories and urban agriculture. International Journal of Agricultural and Biological Engineering 11(1):1–22.

Scott NR. 2021. Evolution of the soil-based agriculture and food system to biologically-based indoor systems. In: Technology in Agriculture, eds Ahmad F, Sultan F. London: InTechOpen.

Tamayo Tenorio A, Kyriakopoulou KE, Suarez-Garcia E, van den Berg C, van der Goot AJ. 2018. Understanding differences in protein fractionation from conventional crops, and herbaceous and aquatic biomass: Consequences for industrial use. Trends in Food Science and Technology 71:235–45.

Timmons MB, Guerdat T, Vinci BJ. 2018. Recirculating Aquaculture, 4th ed. Ithaca Publishing Company.

Ting KC. 2013. A systems concept for controlled environment plant production. Resource Magazine, Mar/Apr.

Ting KC, Lin T, Davidson PC. 2016. Integrated urban controlled environment agriculture systems. In: LED Lighting for Urban Agriculture, eds Kozai T, Fujiwara K, Runkle ES. Singapore: Springer.

Ting KC, Scott N, Mohtar R. 2021. Circular controlled--environment plant production systems. Resource, March/April 2021. ASABE.

van Delden SH, SharathKumar M, Butturini M, Graamans LJA, Heuvelink E, Kacira M, Kaiser E, Klamer RS, Klerkx L, Kootstra G, and 10 others. 2021. Current status and future challenges in implementing and upscaling vertical farming systems. Nature Food 2(12):944–56.

van der Goot AJ, Pelgrom PJM, Berghout JAM, Geerts MEJ, Jankowiak L, Hardt NA, Keijer J, Schutyser MAI, -Nikiforidis CV, Boom RM. 2016. Concepts for further sustainable production of foods. Journal of Food Engineering 168:42–51.

Van Loo EJ, Caputo V, Lusk JL. 2020. Consumer preferences for farm-raised meat, lab-grown meat, and plant-based meat alternatives: Does information or brand matter? Food Policy 95:101931.

WRI [World Resources Institute]. 2019. Creating a Sustainable Food Future: A Menu of Solutions to Feed Nearly 10 Billion People by 2050. Washington.

[1]  Cornell University offers a virtual course on RAS (see

[2]  USDA Economic Research Service, Food availability (per -capita) data system (as of Jul 2021) ( per-capita-data-system/).

[3]  The high cost is also due to the inherent properties (e.g., size and intricate 3D nanostructure) of the photosynthetic proteins of algae and green leaves compared with the proteins of cereals and legumes.

About the Author:K.C. Ting is professor and head emeritus, Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign. Michael Timmons is professor emeritus of biological and environmental engineering, Cornell University. Ricardo San Martin is research director and industry fellow, Alternative Meats Lab, Sutardja Center for Entrepreneurship & Technology, College of Engineering, University of California, Berkeley.