The researchers studied different fertilization methods in chestnut forests to see how they affect soil and crop yield. They tested four treatments: no fertilization, less fertilization, normal fertilization, and more fertilization. They found that adding the right amount of fertilizer increased soil microorganism biomass and enzyme activity. This helped boost chestnut yield, but too much fertilizer had a negative impact. The weight of individual chestnuts didn't change much with different treatments, staying around 8.50-8.85g. Overall, the study showed that proper fertilization can improve soil health and increase crop yield in chestnut forests.