Biobased Materials as Promising Tools for the Slow-Release of Urea

The exponential growth of the world's population in recent years increases the necessity to optimize the technologies associated with the agricultural sector. In this direction, a smart use of fertilizers is able to guarantee high productivity, avoiding problems related to fertilizers losses from volatilization and leaching with consequent pollution issues. An extremely promising solution is represented by slow-release fertilizers (SRFs) that are able to increase the efficiency of fertilizers, lowering their application frequency and preserving the environment but still satisfying the nitrogen requirement of the plants. However, most of the devices used come from non-renewable sources with consequent problems related to environmental pollution. So, in the last years, research efforts moved to materials that present similar release properties but, at the same time, are cheap, environmental friendly and biodegradable. The aim of this Review is to focus on biobased polymeric devices used as slow release systems of urea. In particular, strong attention will be dedicated to different polymers and different formulation strategies in order to understand the high amount of possibilities and performances of these devices.