Urban agriculture attempts to advance sustainable agricultural methods, such as composting, the use of organic fertilizers, and water conservation. It involves a multidisciplinary approach, combining knowledge of soil science, plant physiology, sustainable agriculture, and technology. Crop rotation and companion planting are two other methods urban farmers can utilize to lessen the demand for pesticides and herbicides. The crops are managed using advanced technology involving sensor-based monitoring, automated irrigation systems, and data analysis to maximize crop output. Urban crop farming is regarded as an important agricultural activity for the modern and circular economy, as it can also improve the urban residents’ income and reduce agricultural waste and gaseous emissions from long-distance transportation.
1. Introduction
City residents have practiced urban farming for centuries. In recent years, there has been a resurgence of interest in it because of concerns about urban food access, sustainability, and food security. Due to its potential to support food security and sustainable agriculture, and because of its lesser impact on the environment than conventional agricultural practices, urban farming is becoming more attractive than before. A Michigan State University study has found that traditionally produced food in the USA is transported by an average distance of almost 1500 miles before it arrives on supermarket shelves
[1]. This has many implications, including the unnecessary extra cost of food, increased carbon emission, deterioration of freshness of food, and potential for supply disruption due to inclement weather, pandemics, road closures, strikes, and other causes. For an industrial market economy, such a supply chain is necessary at the present time. However, the practice of urban agriculture can help avoid some of these problems, while also generating part-time jobs.
Urban agriculture attempts to advance sustainable agricultural methods, such as composting, the use of organic fertilizers, and water conservation. It involves a multidisciplinary approach, combining knowledge of soil science, plant physiology, sustainable agriculture, and technology. Crop rotation and companion planting are two other methods urban farmers can utilize to lessen the demand for pesticides and herbicides. The crops are managed using advanced technology involving sensor-based monitoring, automated irrigation systems, and data analysis to maximize crop output. Urban crop farming is regarded as an important agricultural activity for the modern and circular economy, as it can also improve the urban residents’ income and reduce agricultural waste.
Of the eight billion people on earth in 2023, more than 55% are already living in urban areas
[2] (Ritchie and Roser 2018). Agriculture has been a significant source of food, income, and employment, and it can also help to reduce poverty, increase income levels, and promote prosperity for a projected 9.7 billion people by 2050
[3][4]. The urban population is expected to exceed 75% of the total global population by 2050, making urban agriculture even more important. In light of several persistent issues, such as climate change, greenhouse gas emissions, pollution and waste generation, food shortage, and food waste, agricultural growth through traditional farming is constantly in danger
[3]. Weed growth, which annually results in major crop loss, is another serious issue that traditional farmers must contend with
[4][5][6]. Agriculture contributed almost 4% to the global Gross Domestic Product (GDP) in 2018, and it makes up more than 25% of the GDP in some developing nations. Despite the extensive traditional farming, about 9% of the world’s population remained hungry in 2020
[3][6].
Theoretically, to feed the growing population, a cultivation area equal to that of the South American continent is needed. In addition, a farming area consisting of almost the size of the African continent is needed for all the animals that are essential to support human activities. This will require bringing almost 57% of the total earth’s surface under habitation. However, as almost 57% of the earth’s land surface is unhabitable, all human activities must be limited to 43% of the total land surface. Within that 43% area, all types of land use, such as forest, built-up areas, infrastructure, agriculture, water bodies, and various recreational activities, must be accommodated. Currently, of the global land surface, urban areas occupy between one and 3% of the total land area. Concentrating the urban population that would reach 75% of the total global population by 2050 within the urban areas means that urban planning must become smarter than it is today, and that includes the practice of urban agriculture
[2].
The traditional agricultural sector has become a polluting, water-intense, and ecologically damaging industry. Urban agriculture (or farming) could help to offset some of these problems by shifting at least part of the agricultural production to the urban farms. Urban farmers must comprehend how plants grow. This involves being aware of how light, temperature, and water affect plant growth
[7] and knowing how to spot and deal with pests and diseases that could harm plants. Moreover, it is important to know how using nutrient-rich water instead of soil, as with hydroponics, can help plants grow. This method is particularly helpful in urban settings with limited space for farming and generally poor soil conditions. Understanding plant nutrient needs, water chemistry, and environmental controls is necessary for hydroponic farming systems. To limit their production within smaller spaces, urban farmers frequently adopt clever methods such as vertical farming, rooftops, balconies, and communal gardens. To create the optimum plant-growing conditions, farmers need to amend the soil with fertilizers, check for impurities, and keep an eye on the pH (potential for hydrogen) level of the soil. Urban farmers need to control pests without resorting to hazardous chemicals that could endanger either human health or the environment. This could entail utilizing organic pest management techniques, such as companion planting, or the introduction of beneficial insects.
2. Theory of Urban Farming
The first settlements on the earth started in areas with fertile plains. Such settlements later emerged as urban centers, where people from peri-urban areas and remote villages used to have farmers’ markets organized on a regular basis. However, those traditions were not enough to meet the requirements of a large urban population. After the harvest, many agricultural products quickly perished, and they needed to be transported to the consumption sites quickly. Since there were no good transportation networks, many of the products decayed during their long transit. To solve this problem, a German economist and agriculture planner, J. H. Von Thunen (1783–1850), in 1826, using the example of Chicago, argued that city farming should be located centrally within an “Isolated State” (Figure 1).
Figure 1. Von Thunen model of land use. (Adapted and modified from
[8]).
The Von Thunen model developed a theory of marginal productivity by assuming a uniform land surface without any undulation. Land may be rented to grow crops and transported to different households on an oxcart. The cost of any agricultural products would involve the land rent and transportation cost, as given by Equation (1):