Growth and forage quality response of pakchong (pennisetum purpureum × pennisetum americanum) to integrated urea and sheep manure nitrogen management in coastal bangladesh

This study evaluated the effects of integrated organic and inorganic nitrogen fertilization on the growth performance and nutrient composition of Pakchong forage ( Pennisetum purpureum × Pennisetum americanum ) under coastal field conditions in Bangladesh. The experiment was conducted from February to May 2021 in a randomized complete block design (RCBD) with five treatments: T0 (Control), T1 (100% urea nitrogen), T2 (66.67% urea nitrogen + 33.33% sheep manure nitrogen), T3 (33.33% urea nitrogen + 66.67% sheep manure nitrogen), and T4 (100% sheep manure nitrogen), with three replications. Forage was harvested at 60 and 90 days after planting (DAP), and agronomic traits and proximate composition were determined. At 60 DAP, fertilizer treatments significantly affected root length ( p < 0.05), whereas other growth traits showed no significant differences. At 90 DAP, tiller number ( p < 0.01) and stem diameter ( p < 0.05) were significantly higher under the combined urea and sheep manure treatment. Nutritional analysis at 60 DAP showed significant differences in dry matter, crude fiber, and ash content ( p < 0.05). In contrast, crude protein and other nutrient parameters at 90 DAP were not significantly affected by treatments. Overall, crude fiber and dry matter increased with forage maturity, while crude protein declined. The findings suggest that partial substitution of urea nitrogen with sheep manure nitrogen can support sustainable forage production by reducing dependence on chemical nitrogen fertilizer while maintaining acceptable forage yield and quality.