Impact of Fertilization on Productivity and Nutritional Quality of Napier Varieties in Southern Mindanao, Philippines

Aims: This study investigates the effects of fertilizer application on the growth performance, proximate composition, and chlorophyll content of three Napier grass varieties (King, Pakchong, and Juncao) in Southern Mindanao, Philippines. Study Design: Utilizing a Randomized Complete Block Design with a 3x2 factorial arrangement. Place and Duration of Study: The experiment was performed at the University of Southern Mindanao Animal Production Center facilities from January to March 2023. Methodology: The three Napier grass varieties (King, Pakchong, and Juncao) was the first factor, and fertilizer application (with or without) were the second factor. Four blocks were prepared, each containing six plots, resulting in 24 plots. The fertilized plots received two applications of 150kg N/ha and 75kg N/ha of the recommended NPK fertilizer, respectively, while non-fertilized plots did not receive any fertilizer. Results: Results showed that fertilizer application significantly improved herbage yield, with fertilized plants yielding 20.25 tons per hectare compared to 15.14 tons in non-fertilized plants. Pakchong exhibited the highest yield and crude fiber content, while Juncao grass showed higher crude protein content without fertilizer. Fertilization also increased ether extract content, with Pakchong displaying the greatest response. However, nitrogen-free extract (NFE) was higher in non-fertilized plants across all varieties, indicating a complex interaction between nutrient availability and carbohydrate allocation. Conclusion: These findings underscore the importance of targeted fertilizer management to optimize both growth and nutritional quality, depending on specific production goals. The differential responses among Napier varieties suggest the potential for variety-specific fertilization strategies, which can enhance forage quality and sustainability in livestock farming. Further research is recommended to explore the long-term impacts of continuous fertilization and the underlying genetic mechanisms driving varietal differences.