Today we invite you to reflect on the potential of urban areas to produce a significant percentage of the fruit and vegetable that we consume with a view to improving the sustainability of food production. To do this, we will rely on two studies recently published in magazines nature food y Scientific Reports.

But beware! The low productivity from some orchards and the growing contamination in cities they make us have to be careful when selecting suitable areas for urban cultivation and we have to optimize their management, so that the consumption of these foods is safe for our health.

The productive potential of urban gardens

According to the first study, growing only 10% of green areas located in urban centers we could obtain up to 15% of the recommended daily consumption of vegetables. These results come from a study carried out in the city of Sheffield, United Kingdom, with 585.000 inhabitants, where the researchers analyzed the suitability of parks and gardens (common and private) to produce food. They also studied the potential of hydroponic (soilless) and aquaponic (soilless and in combination with aquaculture) crops on terraces and roofs of houses in this English city.

But beware, according to the second study, these figures could be improved. With an optimization of the existing urban cultivation, we could obtain up to half of the vegetables and fruits that we should consume daily. Researchers have analyzed the areas currently used for urban agricultural production in three urban centers in the United Kingdom. The authors note that one of the factors limiting production is the little use of the current spaces dedicated to urban cultivation. The study shows that of the garden cultivation plots they only use 2% of their current surface for cultivation, while only 52% of the surface destined for urban gardens is cultivated. The authors affirm that, maintaining the same cultivation area, but intensifying the use, the production could be optimized if the proportion of land cultivated in private gardens increase up to 30% in gardens and up to 75% in urban gardens, being able in the best scenario, to cover up to half of the demand for fruits and vegetables of the locality itself.

Taken together, the authors demonstrate that with a optimization of urban spaces suitable for agriculture we could produce a substantial amount of food, which would help ease the pressure over other areas where agricultural expansion is producing serious impacts for the biodiversity and on resources as precious as soil and water, the availability of which must be guaranteed to a growing population (study).

It is also important to highlight the benefits it would bring to food security a local provision of food, especially in situations of shortage due to current causes such as epidemics o wars. For example, in the United Kingdom, after the Second World War, the British government activated the 'Dig for Victory' program to promote urban cultivation that could alleviate the lack of food. Currently, urban centers are extremely vulnerable to shortages as production is carried out in rural areas, with urban gardens being an excellent option to ensure food supply.

Limitations and risks of urban agriculture

As we have seen, further development of urban agriculture could increase food security and sovereignty in urban centers, decrease the need for transport - and therefore CO2 emissions - and increase the people's wellbeing of the population through greater social interaction and with nature. However, urban cultivation also has its limitations.

As we showed you a while ago, the productivity of urban gardens can decrease if they are not managed properly, and result in a greater need for inputs and some costes of high production, which would hinder its implementation at a commercial level.

On the other hand, the potential of urban agriculture faces another not so obvious danger: the growing contamination of urban environments as a consequence of traffic. Some studies have shown that vegetables grown in urban gardens exposed to heavy traffic contain levels of heavy metals above what is allowed (studies in Seville, Berlin and Bologna).

Therefore, it would be necessary to carry out previous studies that guarantee the suitability from the growing area (study) and, even better, reduce traffic and pollution in urban environments, not only to favor urban agriculture, but also to reduce the risk of direct death of citizens and to improve their health (study).