Microalgae based biochar application in agriculture / Nur Amirah Huda Abdul Rani

Green algae are highly versatile microorganisms with diverse applications in agriculture, the food industry, and medicine. In agriculture, they play a crucial role in enhancing plant growth by improving soil fertility. This study investigates the potential of green algae-derived biochar as a soil amendment to promote plant growth. Biochar was produced from raw green algae collected from a college drainage system and analysed for its nitrogen content using Elemental Analysis. The biochar was prepared by pyrolyzing dried, shredded green algae (initial weight: 34.57 g) at 350°C and 400°C for 40 minutes. The algae were divided into four crucibles (8.42 g each), and after combustion, the 350°C biochar yielded 13.26 g, while the 400°C biochar yielded 13.05 g. Biochar at each temperature was mixed in a 1:1 ratio by volume with two different plant-growing mediums: cocopeat, and clay soil. The experiment selected the cultiva, water spinach (Ipomoea aquatica) and choy sum (Brassica sp), and then watered by distillation water. Plant height was measured at 12-days intervals during the growing period. The result showed that raw biochar at 350°C in cocopeat can support water spinach plant growth, with the best plant growth of 14 cm, which is the best condition for plant growth. Instead, algae biochar produced with cultured algae at 60°C had lower plant growth, so it showed poor agricultural potential. Overall, increased plant height and growth in the treated soils indicates that raw green algae biochar especially at the pyrolysis temperature of 350°C, can be a potential amendment for sustainable agriculture.