# Promoting Urban Farming for Creating Sustainable Cities in Nepal
## 2 Theory of Urban Farming
For instance, a 0.4 carbon use efficiency (CUE) indicates that 40% of the carbon acquired by plants is taken up for the growth and storage of biomass. The CUE of a plant can be measured through biomass [15; 16], and the total growth of a plant over an urban area can be converted into GPP [17]. It provides a better understanding of the energy exchange between vegetation and the atmosphere by estimating the CUE of a plant and vegetation carbon dynamics (VCD). A phytotherapy process helps to trap many anthropogenic drivers originating from different sources in the urban environment. These analyses shed some light on the rate of carbon allocation and help to accurately quantify the ability of vegetation to convert carbon to new biomass in urban ecosystems. Furthermore, the CUE assessment would provide new insights into vegetation carbon allocation at regional and global scales. An accurate quantification of CUE for various vegetation types would enhance the performance of earth-system-related models. Since urban farming is performed on a smaller scale, it helps to precisely quantify the CUE and assess the VCD for an urban area. The VCD is a measure of the rapid increase in the atmospheric concentration of CO\({}_{2}\) and other greenhouse gases. Assessing the VCD can help to measure the productivity of various plants [18]. Of the global terrestrial land surface, 71% is habitable. Of the 71%, 33% is arable, and 1% is under urban land uses [19]. A major portion of the population is living in smaller urban areas. Since 2007, the percentage of the urban population (50.14%) has exceeded the rural population (49.86%) (Figure 2) [20]. As the urban population increases, many people have to concentrate their activities in even smaller areas that are urban. The rapid growth of urban population has increased food insecurity in cities, and it has overstretched the supply chain, especially at the time of crises such as the COVID-19 pandemic. The United Nations Food and Agriculture Organization (FAO) [21] predicts that, compared to 2022, the global food demand will increase by 70% by 2050. This will put pressure on the already scarce land and water resources. This also means that there is an urgent need for a supplemental approach to address possible urban food shortages. Urban agriculture has the potential to provide safe and easy access to food for hundreds of millions of people. Urban farming is a way to utilize limited land resources to produce food within urban and peri-urban areas and supply it in response to the daily demand of consumers within a town/city. It applies intensive production methods, using and reusing natural resources and organic urban wastes to yield a diversity of crops and  
Figure 2: Global rural and urban population percentages (1960–2020) [20]. livestock to meet urban food needs. Urban farming offers easy access to fresh and nutritious food. This process was officially recognized by the 15 th FAO meeting in January 1999 and subsequently at the World Food Summit in 2002. Since then, its importance has been even more appreciated because, like other service sectors and industries, urban farming provides additional employment and income opportunities for the urbanites. Urban agriculture can create a diverse ecology where fruit trees and vegetables and even fishing could coexist and build an ecologically sustainable circular economy. Since only small land areas are available for farming in the cities, urban farming is often performed on top of hardscape (pavements, sidewalks, rooftops, and balconies). However, only shallow rooting plants can be planted on raised beds on hardscape. In such a hardscape, if animal manure and chemical fertilizers are used, they generate additional greenhouse gases. However, if organic compost is used, it helps sequester atmospheric carbon within the compost and plant bodies, while using 70 less water. In a smaller area, vertical farming is possible by using compost, wherein every layer can sequester carbon.