Development of slow release Zn fertilizer using nano-zeolite as carrier

Zinc (Zn) use efficiency hardly exceeds 2-3% and major portion of added Zn gets fixed in the soil. In order to improve the Zn use efficiency by crops, a laboratory study was undertaken at the Department of Nano Science and Technology, Tamil Nadu Agricultural University, Coimbatore, India, to develop Zn fertilizer using nano-zeolite as a substrate. The natural zeolite (clinoptilolite) was ball milled to achieve nano-dimension (90-110nm) and fortified with Zn by loading Zinc sulphate (ZnSO4). The zeolite was characterized before and after loading of Zn using particle size analyzer, Fourier Transform Infrared Spectroscopy, Raman Spectroscopy, X-ray Diffraction, Scanning Electron Microscope and Transmission Electron Microscope. The data clearly indicated that the nano-zeolite was loaded successfully loaded with Zn to the tune of 14% and Zn presence in the substrate was confirmed by Energy dispersive X-ray spectroscopy and Atomic Force Microscopy. After the synthesis, sorption and desorption pattern of Zn of the nano-zeolite was examined using a percolation reactor. The results showed that Zn release from the nano-zeolite substrate has prolonged for a period of 1,176hrs, while the Zn release from the ordinary ZnSO4 ceased to exist within 216hrs. The data suggest that the nano-sized zeolite is capable of retaining Zn and slowly release into the soil solution, which may be served as a slow release Zn fertilizer and improve use efficiency by crops.