The study looked at how different types of fertilizers affect nitrogen levels in soil being reclaimed after subsidence. Over two years, they found that total nitrogen, microbial nitrogen, and soluble organic nitrogen in the soil increased each year. Using organic manure with inorganic fertilizer was the best way to increase total nitrogen in the soil. Adding fungus fertilizer to organic manure and inorganic fertilizer was the most effective at improving microbial nitrogen and water-soluble organic nitrogen levels in the soil.