Abstract: The study was carried out in field conditions and use conventional compound fertilizer as the control group to explore the effect of compound fertilizers containing 2%, 4%, 6%, or 8% humic acid on the yield and quality of chilli. The effect of humic acid-compound fertilizer treatment under continuous cropping conditions was investigated, 6% humic acid-compound fertilizer was conducted for four consecutive years and using conventional compound fertilizer as the control group. The results show that humic acid fertilization significantly improved the yield and quality of chilli, and the overall improvement was directly proportional to the dosage of humic acid. An evaluation based on benefit, yield, and various quality indicators concludes that compound fertilizer with 6% humic acid was the optimal ratio, which increased the yield by 14.07% in the first year compared to that in the control group. The application of humic acid-compound fertilizer effectively reduced the impact of continuous cropping on the yield and quality of chilli, and the combined decline in the yield and quality was significantly less than that in the control group. In the fourth year, the yield of 6% humic acid-compound fertilizer treatment was 33.6% higher than that of conventional fertilizer.

Key words: humic acid, chilli, yield, chilli quality, continuous cropping