The study compared three plants, Acorus calamus, Pontederia cordata, and Alisma plantagoaquatica, in removing nitrogen from farmland wastewater. Pontederia cordata was the most effective at removing nitrogen, followed by Alisma plantagoaquatica, and then Acorus calamus. Alisma plantagoaquatica had the highest nitrogen adsorption capacity. Pontederia cordata had a strong nitrification-denitrification process, while Acorus calamus relied more on nitrification for nitrogen removal. These findings provide insights into how different plants can help remove nitrogen from wastewater.