Chemical and biological fertilizers affect the seedling development of bell pepper

Objective: Bell pepper (Capsicum annuum L.) is one of the most important greenhouse vegetables. The use of seedlings is a common production method for bell peppers in most greenhouses; therefore, seedling quality has a significant impact on yield. Today, the use of biological fertilizers to replace chemical fertilizers in the production of agricultural products has become important. The present study was conducted to investigate the effect of chemical fertilizers and bio-fertilizers (Nitrokara and Phosphonitrokara) on some seedling characteristics of the bell pepper.Methods: The study investigated how different fertilizer combinations and timing affect pepper seedling production. The first experiment tested the ۲۰N:۲۰P:۲۰K fertilizer, the second tested ۱۰N:۴۵P:۱۰K, both at different application timings. The third experiment examined the impact of biological fertilizers (Nitrokara and Phosphonitrokara) combined with ۲۰N:۲۰P:۲۰K on the seedling growth. All experiments were conducted using commercial bell pepper cultivars Inspiration, Arancia, and Tarento.Results: A fertilization regime of ۲ g/L ۲۰N:۲۰P:۲۰K, applied every three days, improved plant height, root and shoot fresh and dry weight, root volume, leaf area, stem diameter, and chlorophyll index across cultivars. The Inspiration cultivar was more responsive to the balanced NPK, showing high shoot biomass gains, while cultivar Arancia showed a clear trade-off; the balanced NPK favored shoots, while the high-phosphorus fertilizer enhanced roots. Similar pattern to Arancia, the Tarento cultivar with balanced NPK boosting canopy/photosynthesis and with high-phosphorus fertilizer improving roots and, somewhat, the plant height. Although the addition of biofertilizers to the chemical NPK improved root traits and chlorophyll index in some cultivars, they did not compensate for the loss in shoot productivity as the main yield component, compared to the use of NPK alone.Conclusion: The balanced ۲۰:۲۰:۲۰ fertilizer at the rate of ۲ g/L was optimal for maximizing the aboveground productivity and photosynthetic efficiency, while the high-phosphorus ۱۰:۴۵:۱۰ shifted the biomass allocation toward roots, potentially useful for stress conditions.

کلیدواژه ها:

Capsicum annum ، Nitrogen ، Potassium ، Phosphorus