Non tidal lowland soil is a potential land for cultivating green spinach. Even though its natural fertility is low, the land can be improved through fertilization methods using biochar and compost tea derived from natural resources. Therefore, this research aimed to test the optimal doses of lotus compost tea and biochar by using Nitrogen-Phosphorus-Potassium (NPK) fertilizer to enhance nutrient availability in non tidal lowland soil. The results showed that the three types of fertilizers significantly interacted with the chemical properties of non tidal lowland soil (pH, N-total, P-available, K-dd), nutrient uptake of N, P, and K, growth, and green spinach yield. Meanwhile, the combination of 20 tons ha^-1 of biochar with 40 ml tan^-1 of lotus compost tea and 50% NPK fertilizer was the best treatment for enhancing growth, production, and nutrient uptake. This treatment reduced fertilizer use by 50% in non tidal lowland soil and NPK availability correlated positively with the uptake in green spinach plants.

Keywords: biochar, compost tea, spinach, lotus plants, non tidal lowland