Each type of organic material has different nutrient contents that cause varying decomposition rates. Decomposition rates are influenced by cellulose content, lignin, carbon (C), nitrogen (N), and the C/N ratio. This study aims to determine the effect of lignin content in organic materials on soil pH, as well as mineral N and available P nutrients in podzolic soil. The study used a completely randomized design with one factor, treating solid sludge waste from palm oil factories, bagasse waste, water hyacinth, woodash and bulrush at a nitrogen dosage of 135 kg N ha^-1 per treatment. Each treatment was replicated four times. Incubation was carried out for two weeks and four weeks, with 24 experimental pots for each incubation period, resulting in a total of 48 pots for the entire experiment. The results showed that the application of several organic materials with different lignin contents had an effect on soil pH, mineral N, and available P in podzolic soil.