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Urban agriculture is a continuously growing field that offers alternative spaces for vegetable production in urban areas. Urban communities in bigger cities all around the world benefit from creating green roof spaces to grow vegetables which facilitates the integration of agriculture. However, there are still some challenges that restrict the widespread use of green roofs and question the sustainability of this approach.
Urban agriculture enhances the urban food movements in big cities by providing an alternative source of fresh and locally produced food. The utilization of limited spaces with small-scale farming techniques contributes to the increase of production in urban farms compared to the produce from rural areas.
Urban agriculture faces challenges because of the lack of available space in cities due to building constructions. Urban agriculture struggles to meet the demands for locally produced food, and green roofs provide an alternative to green spaces and increase localized urban agriculture.
Rooftop gardens have numerous ecological and economic benefits. These include stormwater management and energy conservation. Moreover, local food production provides a way to reduce carbon dioxide emissions by reducing the distance from where the food is produced to where it is consumed.
Southern Illinois University Carbondale (SIUC) Green Roof: Vegetable Research
Studies conducted on the SIUC green roof prove the suitability of the system for numerous vegetable crops production. This research has pointed out the importance of a good fertility management systems that provide essential amounts of mineral nutrients and maintaining moisture levels to aid optimal growing conditions.
The study was conducted in the autumn growing season. The study aimed to determine the effectiveness of different fertility systems for the growing of shallow-rooted vegetables such as kale, lettuce, and radish. Results from the study revealed that all crops used could be produced in an extensive green roof system giving that appropriate nutrition is provided.
The increasing demand for locally produced foods and the available opportunities and space in urban areas food production programs for green roofs are becoming more and more popular.
Sustainability of Green Roofs
Green roofs increase the sustainability of building by providing insulation during the winter and reducing the need for air-conditioning during the summer. The reduced need for air conditioning and heating reduces the overall energy consumption of buildings and the carbon footprint of the building.
Furthermore, by protecting the roof from the harmful influence of the sun, wind, and rain, green roofs extend the life span of the building infrastructure. According to research, roof surfaces last almost three times longer if a green roof is in place. Also, by holding the excess rainwater and thus providing a gradual release of the rainwater into the sewage system, green roofs help prevent flooding.
Another positive feature of green roofs is that they provide a ground for biodiversity development. They provide shelter for birds, bees, and other insects.
Green roofs help improve the quality of the air by removing gaseous pollutants and dust particles from the immediate surroundings. Given the plant’s living process via photosynthesis, research has shown that under optimal conditions, a square meter of a green surface is estimated to take up 14.41g of carbon dioxide and release 9.68g of oxygen within 12 hours period.
Another environmental benefit associated with green roofs is their ability to reduce the urban heat island effect. This refers to the difference in temperature between urban areas and the surrounding countryside. In the metropolitan cities, this difference can be up to 5 degrees Celsius because buildings reflect and radiate solar energy without dissipating fully overnight. The green roofs help absorb a portion of this heat and the natural evaporation from the plants and soils help cool and humidify the air in the surrounding environment.
Food production on a building has many environmental, social, and economic advantages. Green roof space creates opportunities for expanding urban agricultural food production. Several big cities like Montreal, Toronto, and New York have developed large-scale vegetable production of green roofs. Green roofs provide a sustainable way of producing fresh vegetable, enrich urban biodiversity, and reduce food insecurity. This is also a way of utilizing spaces that are typically unused.
A range of vegetables and herbs can be grown on green roofs; thus not only benefiting the direct consumers but also contributing to a more sustainable lifestyle. By improving air quality, reducing the urban heat island effect, and providing a solution for rainwater management, green roofs become one of the ways for fighting air pollution and global warming. The sustainable nature of this approach can help reduce human carbon footprint and benefit the urban communities by connecting urban consumers to their food, educate the communities about food production and create a future for local, fresh production of food in urbanized areas.