The Controller of Patents at the Patent Office in Chennai has granted a process patent to Tamil Nadu Agricultural University for the invention of a slow-release nanocomposite nano-fertilizer and the method thereof. The patentees of the invention are Ms.M.Latha, Dr.K.S.Subramanian, and Dr.D.Jeya Sundara Sharmila.
To address the issue of foliar spraying in nano-fertilizer formulations, TNAU has pioneered and developed a nano-urea fertilizer suitable for soil application. In this invention, biomass-derived lignin was used as a matrix to entrap urea molecules cross-linked with citric acid and the cationic natural polymer chitosan, which was used as an encapsulant. Studies conducted in a percolation reactor showed that the nitrogen (N) release of normal urea ceased after four days, while the new form of urea, with an N content of 33%, enabled sustained release for up to 30 to 35 days in lightly structured soil. This sustained release of nutrients will contribute to improved nitrogen use efficiency while minimizing nutrient losses to the environment.