Biobased: Biostimulants and biogenic nanoparticles enter the scene

Anthropogenic activities generally consume non-renewable resources and release polluting substances into the environment. Concerning agriculture, the cropping systems are almost based on exploiting non-renewable resources. In recent years, increasing interest has been devoted to reusing agricultural, food and other biomass wastes, considered relevant as they can be seen as resources rich in compounds that can find numerous applications. Biomass biorefining has been successfully applied and has opened up sustainable alternatives to the disposal of agricultural, agroindustrial and food wastes. In this area, an emerging, smart and environmentally friendly way to reduce the impact of waste on the environment is to obtain innovative materials for agriculture. Therefore, as part of biobased strategies, the use of waste biomass to obtain biostimulants and biogenic nanoparticles for crops has recently been proposed. Some research has shown that appropriate biostimulants and biobased nanomaterials have the potential to counteract some of the problems that plague agriculture. The above materials can improve crop performance, enhance crop tolerance to biotic and abiotic stresses, and improve plant nutrition. In light of the above, this review aspires, in the first part, to provide an overview of the ideas and central points that characterize the concept of bioeconomy and circular economy. In the second part, on the other hand, the most recent studies related to the valorization of various types of wastes leading to innovative biobased materials and their application in agriculture are presented. In particular, biostimulants and nanoparticles obtained through biogenic synthesis using agroindustrial and plant residues have been considered. In conclusion, the studies reported in this review show that the use of some biomasses to obtain the above materials represents a sustainable way of waste management and valorization, enabling innovative biobased materials for agriculture.