Hydrochar preparation from wild weeds (Amaranthus sp.) and its application as artificial soil for hydroponic system

Hydroponics is a viable alternative for urban contexts with limited resources and space since it offers efficient and low-maintenance planting methods. This study specifically examines the development of synthetic soil by utilizing hydrochar obtained from wild weeds (Amaranthus sp.). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscopy (FE-SEM) were used to study the hydrochar after it was made using the hydrothermal carbonization method. The analysis showed that the hydrochar had an undefined crystal structure and an uneven, varied porosity. The expansion capacity test clearly showed a significant growth potential of 32%. Nevertheless, the water retention tests revealed a progressive decline in the capacity to retain water as time passed. The kinetics model was used to simulate the release of NPK from the counterfeit soil. The P and K components adhered to a first-order model, but the N elements adhered to the Kosmeyer-Peppas model. The use of artificial soil as a substrate for kale plants had excellent outcomes, with the highest growth rate of 0.75 cm reported on day 7. Subsequently, the growth stabilized and gradually decreased to 0.3 cm by day 21. Hydrochar generated from wild weeds (Amaranthus sp.) is a practical choice for hydroponic farming systems, as it provides fertilizer storage and slow-release advantages.