Optimisation of the amount of nitrogen enhances quality and yield of pepper

Abstract

The goals of this study were to explore the characteristics of nitrogen (N) absorption and utilisation of chilli peppers (Capsicum annuum L.), improve the utilisation rate of nitrogen, and provide a theoretical basis for scientific fertilisation. In this experiment, pepper cv. Huoyanjiaowang was used as the material, and potted sand cultures and field randomised block experiments were conducted to study the effects of fertilisation of different forms of nitrogen on the photosynthetic characteristics, chlorophyll, nitrate nitrogen, alkaline nitrogen, capsaicin, dihydrocapsaicin and yield. In the pot experiment, the nitrogen application rates were 0, 10, 100, 320 and 600 mg/L, a level of nitrogen of 100 mg/L significantly inhibited the growth of pepper. With the increase in the application of nitrogen, the photosynthetic capacity gradually decreased, and 10 mg/L was the optimal nitrogen level. Under 0 and 10 mg N/L nitrogen levels in the field experiment, the content of chlorophyll of this group was significantly lower than those of other treatment groups, indicating that the plot lacked nitrogen. With the increase in the level of application of nitrogen, the contents of nitrate nitrogen and alkaline hydrolysis nitrogen in the soil increased. The yield of 153.18 kg/ha and 230 kg/ha nitrogen treatments was relatively high. Therefore, among the five nitrogen treatment levels, treatment with 153.18–230 kg N/ha was the most effective at stimulating the growth and yield of pepper.