The study looked at how nitrate moves in purple soil when different types of fertilizers are used. They found that nitrate moved differently in the soil depending on the type of fertilizer used. Chicken manure released nitrogen quickly, while pig manure released it slowly. Mixing straw with chemical fertilizer helped keep nitrate in the soil. Overall, using a mix of pig manure or straw with chemical fertilizer can help keep soil nitrate from leaching and improve nitrogen recovery and crop production.