Effects of Integrated Management Strategies on Pepper Yield and Quality: A Study of Cultivation and Nutrient Management Practices

Integrated agronomic management strategies, including nutrient management, planting density, and cultivar selection, are crucial for improving vegetable yield and quality. Here, we conducted a 2-year field experiment to examine the effect of cultivars, planting density and optimal nitrogen application rate on pepper yield, nutrient absorption and quality, and further screened the suitable cultivars and planting density. The experiment included two N application rate treatments (0, 250 kg ha−1), five pepper (Capsicum annuum L.) cultivars (‘Xin xiang #8’, ‘King’, ‘Strip pepper #28’, ‘Er jing tiao’, ‘Red pepper #425’), and three planting density treatments (0.4 m × 0.6 m; 41,667 plants ha−1, 0.5 m × 0.6 m 33,333 plants ha−1; and 0.6 m × 0.6 m; 27,778 plants ha−1). Our results showed that the optimal N application rate can significantly increase the yield, nutrient absorption (e.g., N accumulation) and quality (e.g., Vitamin C content) by 23.7–120.2%, 66.1–125.5%, and 1.0–20.0%, respectively. Different cultivars had different responses to N-fertilizer. Under the optimal nitrogen fertilizer rate, ‘King’ and ‘Strip pepper #28’ had the strongest response to N, and their yield, nutrient uptake and quality (e.g., VC content) were significantly higher than those of other cultivars by 3.4–56.7%, 22.7–227% and 21.3–42.0%, respectively. The highest index of Nutritional Quality (INQ) values for Fe, Mn, and Cu were found in ‘Er jing tiao’, and the highest INQ values for Zn and VC were found in ‘King’, indicating that ‘Er jing tiao’ and ‘King’ have greater nutritional value. In addition, the yield and aboveground dry matter biomass accumulation increased with increasing planting density. Therefore, integrated agronomic management measures, which included high-yield cultivars (‘King’, ‘Strip Pepper #28’), suitable planting density (0.4 m × 0.6 m) and reasonable nutrient management, could be a potential strategy to achieve a high yield and quality of pepper production in southwest China. This study serves as a practical example for the highly efficient development of vegetable production in southwest China.