Optimization of Inorganic fertilization for plantain (Plantago major L.) cultivation as a nutrient-rich feed for herbivorous small pets

With the growing interest in companion animals, there is a corresponding increase in the diversity of the required feeding materials. Particularly, plantain (Plantago major L.) has been newly considered a beneficial feeding material for promoting the health of herbivorous small pets and achieving nutritional balance. However, its optimum fertilization strategy has been rarely investigated so far. This study focused on suggesting optimum fertilization level to maximize the biomass productivity and its nutritional value as the feed, including crude protein, phosphorus, and calcium etc. A pot experiment was conducted with different fertilization regimes (N, P₂O₅, and K₂O) at four application levels [0%, 100% (N-P₂O₅-K₂O = 150-100-200 kg ha⁻¹), 200%, and 300%]. Our results showed that the highest biomass productivity was found at the 100% treatment with the application level of inorganic fertilizers. Based on the quadratic regression analysis, the maximum plantain shoot biomass productivity was estimated when 320 kg ha⁻¹ of N, 185 kg ha⁻¹ of P₂O₅ and 296 kg ha⁻¹ of K₂O were applied as the optimum fertilization level, showing 7.5 g d.w pot⁻¹, 7.2 g d.w pot⁻¹ and 7.1 g d.w pot⁻¹, respectively. Irrespective of fertilization regimes, the overall chemical composition and feed value of plantain showed no significant differences among treatments. Notably, the high Ca/P ratio, reaching approximately 2, indicates the plantain is qualified as a feeding material for herbivorous animals. In conclusion, our study offers valuable insights into optimal inorganic fertilization levels to maximize plantain biomass and enhance its nutritional value for herbivorous small pet feed, with potential benefits for the agricultural and feed industries. However, additional field experiments should be required to determine more accurate fertilization levels, possibly considering different experimental conditions such as soil fertility and planting density.