Controlled Environment Agriculture (CEA), also known as greenhouse agriculture is a modern technology-based farming such as Indoor farming or vertical farming where crops are grown in controlled environments (Temperature, Humidity, Light, Co2 etc.). It refers to all indoor agriculture where certain aspects of the environment are controlled via technologies such as artificial light, hydroponics and aquaponics. Here, mainly produces Cherry tomatoes, lettuce and capsicum. Unlike traditional farming, controlled environment agriculture uses environmentally friendly technology to produce climate resistant crops as well as nutrient rich crops.
History traces the beginning of greenhouse agriculture to the early 1st century. The Roman emperor Tiberius had a habit of eating fresh cucumbers in daily meals. But the problem was in winter. Fresh cucumbers weren’t grown in the frozen state.
So greenhouse agriculture was invented following efforts to produce cucumbers at a controlled temperature even in winter for the king. In the 14th century, Korea has a record of cultivating medicinal plants in controlled temperatures and environments. In the 17th century, many people started greenhouse agriculture in England and the Netherlands to get fresh crops even in the winter season. Technological excellence and the urge to grow own’s food led greenhouse agriculture not only in cold climate countries, but also in desert countries.
Therefore, the more Prominent controlled environment agriculture has been emerged since the first modern greenhouses were developed in the 19th Century by French botanist Charles Lucien Bonaparte in Leiden, Netherlands. Over the years, greenhouses and other indoor growing methods have evolved and proliferated. Nowadays, Spain, China, Japan, Russia, Israel and so many other developed countries have developed and marketed indoor multilevel farms with impressive production statistics. For example, one Japanese farm comprises 25,000 square meters producing 10,000 heads of lettuce per day (100 times more per square foot than traditional methods) with 40% less energy, 80% less food waste and 99% less water usage than outdoor fields. According to the university of California, there are 9 million acres of controlled environment agriculture worldwide. The goal of this form of Agriculture is to utilize scientific data and engineering in order to optimize the Plants growth, reduce pests and diseases and achieve the maximum yield with the minimum input of energy.
Greenhouses are an enclosed structure with its walls and roof typically made of transparent material relying on the sunlight, using artificial light sources (LED) as a supplement. This setup can be used to cultivate plants, protecting them against external influences such as extreme climate events (droughts, cold snaps), pests and wildlife.
Greenhouses come in different forms. In cold temperature areas, greenhouses can be equipped with heat insulation. In general, it can be said that their energy-savings compared to Plant Factories are 60% to 80% due to the utilization of sunlight. Their performance is heavily dependent on the amount of light that can be transmitted through its walls. The greenhouse walls and ceilings can either be decorated with glass or plastic. The traditional choice of glass has a long history of being used for greenhouses whereas plastic is relatively new to the scene. Both glass and plastic have to be able to transmit in the Photosynthetic Active Radiation (PAR) range. The transmittance is affected by several parameters, e.g. if its glazing is single or double-layer or if special additives are included in the material. Intensity being equal, direct and diffuse light both provide photosynthesis equally, but it is believed that diffuse light is more advantageous due to its ability to reach the lower plant leaves which would otherwise be shaded by the upper leaves under direct incident light.
When it comes to utilizing on the greenhouse heating effect, glass has traditionally been an excellent barrier to infrared transmission, which means that the greenhouses lets light enter through the glass and thereby manages heat better than plastic does. When it comes to cost and maintenance, both glass and plastic offer their perks. Glass can break, and plastic can tear. A break in glass is easier to patch up, but costlier to replace. Glass is fragile and more likely to break in certain situations such as closing a cold frame. On the contrary, glass is more durable and lasts longer which translates to less time having to purchase, transport and install than with plastic which needs to be replaced frequently.
In recent years, the concept of cultivating plants in a controlled environmental method, using primarily artificial light sources instead of relying on the sun has gained more prominence.
The differences between cultivating crops in a greenhouse and a plant factory:
Both greenhouses and plant factories use relatively same technologies but there are some key differences regarding the controlled parameters that need to be put into consideration during design and operational phase.
Traditionally, greenhouses mainly produce vegetables, flowers, fruits, starting from seedlings to the fully-grown plant where the plants are typically planted horizontally. The cultivation medium can be soil hydroponic, mist aeroponic or aquaponic. On the other hand, the plant factory mainly grows lower plants such as leafy vegetables, low ornamental plants, high value-added herbs and some seedlings. They use the same cultivation medium as greenhouses.
Greenhouses are generally equipped with a venting system, where the position and size of the vent are determined according to the actual local conditions. The main function of the vents is to release heat to cool down the inner temperature, but also for dehumidification and increment of CO2, as well as to discharge of harmful gases if necessary. Ventilation fans are also be installed to increase the air circulation and to ensure uniformity of gas conditions within the greenhouse. A good ventilation is also important to plant factories. This can be done with ventilation fans, as they are used in greenhouses.
In photosynthesis, CO2 is converted into carbohydrates, which plants need as energy source. In greenhouses, the concentration of carbon dioxide can be increased by adding organic fertilizer, rational ventilation, burning biogas/coal, and chemically producing carbon dioxide. In plant factories the CO2 concentration is mainly increased by releasing it into the room. This method is easy to operate and the concentration easy to control. Greenhouses use primarily sunlight and use artificial light as a supplemental light to increase the light intensity at cloudy days or evening time. Plant factories exclusively use artificial light sources, such as high-pressure sodium lamps, high-frequency fluorescent lamps, and LED luminaires. This gives them a higher control over the plant development enabling them to enhance crop quality, taste and appearance.
Both greenhouses and plant factories provide plants with a more compatible environment for growth but in contrast, greenhouses are less automated and
environmental controls are less precise than plant factories. In general greenhouses utilize single or double layers. This means that the land utilization rate is low compared to plant factories. However, due to lower the construction and operating cost greenhouses remain one of the main setups in agriculture.
The Interrelation between CEA and Sustainable Development Goals (SDGs):
The United Nations Sustainable Development Goals (SDGs) are 17 goals with 169 targets that all 191 UN Member States have agreed to try to achieve by the year 2030. The Sustainable Development Goals are the blueprint to achieve a better and more sustainable future for all. They address the global challenges we face, including poverty, hunger, inequality, climate change, environmental degradation, peace and justice.
The rate at which world’s population is increasing, there is no other option but to increase food production at the same rate. By 2050, the world’s population will reach 10 billion. In order to meet the food demand of this increased population, the rate of food production must increase. But crop land is decreasing at a significant rate every year. As a result, the method of growing more crops on less land has to be adopted for the production of food for the increased population on the gradually decreasing cropland.
In this regard, controlled environment agriculture can be the best method of farming that can fulfill the growing demand for food production. CEA can significantly contribute to avoiding global hunger in light of population growth.
Not only can it produce nutritious and diverse crops towards meeting basic human dietary needs, but CEA also offers the opportunity to develop new varieties of seeds with enhanced crop resilience for better climate adaptation. As demand for food production continues to rise, it is clear that in order to meet the challenges of the future in terms of food security and environmental sustainability, radical changes are required throughout all levels of the global food system. Controlled Environment Agriculture (CEA) (indoor farming) has an advantage over conventional farming methods in that production processes can be largely separated from the natural environment.
Thus, production is less reliant on environmental conditions and pollution can be better restricted and controlled. While output potential of conventional farming at a global scale is predicted to suffer due to the effects of climate change, technological advancements in this time will drastically improve both the economic and environmental performance of CEA systems.
While the conventional agriculture is directly related to local environmental conditions, the needs of CEA systems are drastically different. Commonly-used CEA systems such as hydroponics and aeroponics are able to grow crops in inert mediums (e.g., rock wool, saw dust, coconut husk and hemp) and do not require soil.
Therefore, large-scale CEA operations can be carried out on land where soils are considered barren or contaminated, as the crops are not grown using the terrain itself. This means that CEA systems can in theory be built and thrive in any location, including deserts, tundra or industrial urban areas.
Thus, CEA can produce year-round crops and achieve the zero hunger target all across the world.
Author is a student
Department of Environmental Science and Engineering, Jatiya Kabi Kazi Nazrul Islam University, Trishak, Mymensingh