Addressing Shortages with Storage: From Old Grain Pits to New Solutions for Underground Storage Systems

In every era, climate variability and frequent food shortages have made it necessary to store harvested grains for more than one season. Underground grain storage has been used since ancient times throughout the world. Italy (Cerignola) and Malta (Valletta and Floriana) have preserved rare examples of more recent (from the 16th century onward) large concentrations of grain pits, capable of accumulating substantial reserves to cope with famine or siege. No longer in operation, they represent an important part of the cultural heritage of the agricultural economy. The purpose of this narrative review was, after a geographical framing of grain pits in the Eurasian and African macro-areas, to take the Italian and Maltese grain pits as historical case studies to draw attention to the reevaluation of underground grain storage in the context of climate change and food insecurity. Today, as in the past, grain reserves play a significant role in food security in developing countries and, due to climate change and geopolitical events that can cause disruptions in grain supplies, are also increasingly important for developed countries. A comparison of traditional and modern underground storage systems reveals the great flexibility of this technology, ranging from basic pits of different sizes to large underground granaries equipped with a support structure. The advantages of underground storage, such as environmental sustainability due to thermal insulation of the soil and airtight conditions that make high energy inputs for grain cooling and pesticide use unnecessary, are still useful today, perhaps more so than in the past. Prospects for development include technical solutions involving the application of innovative information technology-based monitoring systems and the use of modern materials to ensure the performance of waterproofing, seepage control, and static safety, all tools for further evolution of this ancient storage system.