Preparation of NPK nanofertilizer based on chitosan nanoparticles and its effect on biophysical characteristics and growth of coffee in green house

NPK nanofertilizer was prepared by loading nitrogen (N), phosphorous (P) and potassium (K) into chitosan nanoparticles. The chitosan nanoparticles were prepared via ionic gelation of tripolyphosphate and chitosan solution. The chitosan nanoparticles were characterized by SEM, TEM, zeta potential and size distribution. The results showed that size distribution was from 300 to 750nm and zeta potential of around 50mV. The released kinetics of nitrogen, phosphorous and potassium in nanofertilizer were also investigated for 240h. The nanofertilizer was applied to coffee seedlings in a greenhouse condition. The results showed that the nanofertilizer enhanced uptake of nutrients, photosynthesis and growth of coffee plants. Application of the nanofertilizer improved 17.04% nitrogen, 16.31% phosphorous and 67.50% potassium content in the leaves of treated plots compared to the control; total chlorophyll content increased up to 30.68% and 71.7% of photosynthesis net rate. Application of nanofertilizer also enhanced leaf number, plant height and leaf area of the coffee seedlings. Using the nanofertilizer may be a potential way to enhance use efficiency of fertilizers for coffee.