Effects of different organic and chemical fertilizers on pasture biomass and botanical composition in Bolu-Aladağ

This study investigates the effects of various fertilizer sources on the biomass yield of vegetation to enhance the productivity and sustainable management of pasture ecosystems. The research was conducted in the pasturelands of the Aladağ Forest Management Directorate in Bolu, Turkey, using a Randomized Complete Block Design with three replications. The treatments—including control, chemical fertilizer, varying doses of liquid vermicompost, and sheep manure—were analyzed based on their impacts on grasses (Poaceae), legumes (Fabaceae), and other botanical families.
The results demonstrated that chemical fertilization accelerated vegetative growth, yielding the highest biomass particularly within the grasses family (438,331 g/m2). In the legumes family, sheep manure and low-dose vermicompost provided sustainable results competitive with chemical fertilization. While "other families," representing low-quality and invasive species, remained dominant in unfertilized control plots, fertilization was found to suppress these groups, providing a competitive advantage for high-quality forage plants. Furthermore, yield variations across blocks highlighted the restrictive role of locational factors on fertilizer efficiency. In conclusion, the selection of fertilizer sources based on the target botanical composition is of critical importance in pasture improvement strategies.