The pressure of urbanization and population growth has resulted in the spread of agricultural areas and the intensification of food demand. To address such demands, controlled environment agriculture (CEA) over recent years has provided a new pathway towards food security and resource circularity.
The environmental challenges of modern agriculture
The rapid growth of human populations has increased the pressure on food production. According to the Intergovernmental Panel on Climate Change (IPCC), agriculture is the largest emitter of greenhouse gasses and accounts for approximately 10-12% of total emissions alone.
Agriculture not only releases carbon dioxide but also methane and nitrous oxide emissions from livestock, rice cultivation, and synthetic fertilizers, which are key drivers contributing to global warming and the loss of biodiversity.
In recent years, sustainable agricultural practices have been implemented to limit emissions. Strategies such as agroforestry, precision farming, and improved manure management all help mitigate greenhouse gas emissions and promote more climate-friendly food systems.
By promoting long-term land management, reducing external inputs such as fertilizer, and adopting efficient resource usage, modern agriculture is gradually transitioning away from unsustainable methods of production.
What is Controlled Environment Agriculture (CEA)?
Controlled Environment Agriculture (CEA) refers to the cultivation of crops within enclosed environments where environmental conditions are carefully regulated. CEA typically includes indoor agriculture (IA) and vertical farming and allows control over temperature, humidity, lighting, and CO2 levels. In turn, this creates an optimal growing environment for the cultivated crops.
According to a 2021 review of CEA literature by Engler and Krarti, CEA has the potential to transform food production within urban centers to supply large populations as well as progress in the global climate goals.
The review highlights how control of the physical environment can reduce the consumption of electricity by up to 75% in several CEA case studies while maximizing crop production. The use of CEA also improves resource efficiency and minimizes the reliance on external factors like weather and seasonal variations.
Core principles of CEA include the optimization of conditions, as mentioned previously, the circularity of resources, and the use of advanced technologies. These principles are closely associated since technologies, including climate control systems, artificial lighting, hydroponics or aeroponics, and integrated pest management, enable condition optimization and reuse of resources.
Additionally, CEA systems can be tailored to specific crop requirements, allowing for the cultivation of a wide range of plant species in diverse geographical locations, including urban areas where arable land may be limited.
The Need for Controlled Environments
The steady rise in CEA has been driven by climate variability, land scarcity, and water scarcity. Such stressors are mitigated since CEA does not depend on unpredictable weather patterns, enabling year-round crop production in controlled environments unaffected by external climate conditions.
Moreover, by using urban spaces and implementing efficient water management techniques, CEA addresses the challenges posed by limited land availability and water resources, making it a sustainable approach to agricultural production.
The growth of CEA was documented in a review by Ragaveena et al. (2021) in which researchers highlighted the rising popularity of hydroponics, aquaponics, nutrient film technique and aeroponics since 1999. Soil-less agriculture has become increasingly more efficient because of its popularity. However, the review highlights the importance of monitoring solutions in CEA to maximize crop production.
Monitoring in CEA typically consists of various components to regulate temperature, humidity, and lighting. Temperature control is achieved through heating and cooling systems, such as HVAC (Heating, Ventilation, and Air Conditioning) units, which maintain the ideal temperature range for plant growth. Humidity control involves humidifiers and dehumidifiers to adjust moisture levels, providing a suitable environment for plants. Lighting systems, such as LED lights, are employed to provide the necessary spectrum and intensity of light for photosynthesis, allowing plants to grow efficiently in indoor settings regardless of natural light availability.
Sustainability in Farming
Since the first development of CEA, strategies have been implemented to improve the sustainability of CEA techniques. The use of CEA in urban areas also reduces the conversion of natural habitats for agriculture. Further, CEA improves resource efficiency by optimizing water usage through the use of recirculating internal systems and reduces the need for external inputs, such as pesticides and herbicides, since the environment is controlled.
Additionally, CEA reduces carbon dioxide emissions associated with food transportation since crops can be grown closer to consumer centers, thus reducing transportation. Similarly, CEA also allows farmers to produce non-local crops not well suited for the climate of the areas, thus expanding the variety of available produce for consumers.
However, emissions from CEA vary widely depending on factors such as aeration conditions and feedstock composition. A review of CEA case studies by Thomson et al. (2022) found that CEA emitted CO2 at varying rates ranging from 0.32 to 429.27 g CO2–C per kg of lettuce grown per day, depending on the aeration conditions and feedstock composition. Therefore, although CEA is an alternative system reducing the impacts associated with traditional agriculture, the emissions of CEA itself require consideration.
Innovation and Technology
In a study considering the performance indicators of CEA, Benke, and Tomkins (2017) discussed how the performance of CEA is limited by start-up costs, energy consumption, number of crop types, as well as production volume and scaling-up. Such limitations dampen the rise of CEA systems. However, the use of emerging technologies may overcome such challenges.
Technological innovation is a key principle of CEA in improving system efficiency and overall productivity. Systems particularly important to CEA include climate control systems that use automated sensors to adjust environmental factors. Improving the accuracy of such sensors will, therefore, directly translate to healthier, more productive crops.
Reducing the cost while improving the accuracy of sensors may be particularly valuable in reducing the start-up costs and energy consumption mentioned in the review by Benke and Tomkins (2017).
Other technologies valuable to CEA include lighting technologies, particularly LED systems, that enable the customization of light sources, intensities, and spectrum, modifiable to the different crops and their growth stage. Energy efficiency while accelerating crop growth would contribute greatly to the optimization of CEA.
Cutting-edge technologies, therefore, contribute to the improvement of CEA by maximizing the potential productivity of indoor farming. In turn, technologies may be an essential component in the transition towards more sustainable agricultural production.
- Benke, K. K., & Tomkins, B. (2017). Future food-production systems: vertical farming and controlled-environment agriculture. Sustainability: Science, Practice and Policy, 13(1), 13–26. doi:10.1080/15487733.2017.1394054
- Engler, N., & Krarti, M. (2021). Review of energy efficiency in controlled environment agriculture. Renewable & Sustainable Energy Reviews, 141, 110786. doi:10.1016/j.rser.2021.110786
- Ragaveena, S., Edward, A. S., & Surendran, U. (2021). Smart controlled environment agriculture methods: a holistic review. Reviews in Environmental Science and Bio/Technology, 20(4), 887–913. doi:10.1007/s11157-021-09591-z
- Thomson, A., Price, G., Arnold, P., Dixon, M., & Graham, T. (2022). Review of the potential for recycling CO2 from organic waste composting into plant production under controlled environment agriculture. Journal of Cleaner Production, 333, 130051. doi:10.1016/j.jclepro.2021.130051