Environmentally Benign Synthesis of Metal Nanoparticles for Fertilizer Applications in Agriculture

The application of nanotechnology has significantly increased in different branches over the last few decades. The agricultural sector has also embraced nanotechnology by employing different metal nanoparticles (MtNPs) in various fields. The conventional physical and chemical methods of metal nanoparticle synthesis involve harsh operating conditions and are known to use and generate hazardous chemicals and substances that may pose substantial risks to human health and the environment. As a result, researchers have shifted their focus to environmentally benign, economically viable, and sustainable biological methods for synthesizing these metal nanoparticles (NPs). These biologically derived NPs may enhance the productivity of agroecosystems by acting as nanofertilizers, nanoplant growth promoters, nanopesticides, nanoherbicides, nanonutrient carriers, etc. The slow-releasing properties of MtNPs enable them to be used by plants efficiently and prevent them from going into unintended ecosystems. This chapter summarizes various biogenic or green synthesis methods of metal nanoparticles involving different plant parts such as root, stem, leaf, and gum and microorganisms such as bacteria, algae, and fungi. A brief description is also given of various characterization techniques typically employed for MtNPs. This chapter also discusses the latest advances in various applications of MtNPs in the agriculture sector toward achieving food security and environmental sustainability.