Improving the growth of Centella asiatica using surfactant modified natural zeolite loaded with NPK nutrients

There is great interest in using sustainable fertilizer to enhance medicinal plant quality such as Centella asiatica, which is known for its various medicinal properties. Here, we examined the performance of NPK-Organo-Zeolite (NPKOZ) as a controlled release fertilizer for the growth of C. asiatica. Natural zeolite that has been modified with surfactant hexadecyltrimethyl ammonium (HDTMA) and addition with ammonium (N), phosphate (P) and potassium (K) was characterized with X-ray diffraction and Fourier transform infrared spectroscopy. In a leaching study, it was found the NPKOZ showed fewer losses of nutrients. For the plant growth study, a comparison was made with eight different treatments including chemical fertilizers monoammonium phosphate and monopotassium phosphate for 70 days. Morphological (number of flowers, branches and leaves, specific leaf area and plant biomass) and biochemical growth parameters (N, P, K and chlorophyll contents) of the plant were analysed. Second cultivation was also conducted to compare potted, hydroponic and verticulture systems with or without NPKOZ. The NPKOZs treatments resulted in the highest number of leaves, branches and flowers among all treatments. In addition, the chlorophyll contents were also the highest with NPKOZs application. The NPK contents in the C. asiatica plants were comparable with that of chemical fertilizers tested. This study showed that NPKOZ fertilizer with verticulture system is a suitable sustainable controlled release fertilizer for the improvement of the growth of C. asiatica.