Assessing the Feasibility of Using Poultry Manure as a Beneficial Fertilizer for Forage Sorghum (Sorghum bicolor (L.) Moench) Cultivation

Poultry farms’ waste is rich in several nutrients and minerals and is widely utilized for soil fertilization. Forage sorghum (Sorghum bicolor (L.) Moench) is a vital crop for livestock feed and therefore demands efficient nutrient management to enhance its growth and yield. Therefore, this study focused on utilizing poultry manure for forage sorghum cultivation. In this study, a greenhouse experiment was conducted to study the effect of varying doses of poultry manure on soil properties and cultivated forage sorghum. The results showed that mixing poultry manure led to a significant (p < 0.05) increase in soil nutrients and the concentrations of nine heavy metals (Cd, Co, Cr, Fe, Mn, Ni, Pb, and Zn). The best performance of forage sorghum was observed at a 10 g/kg poultry manure treatment, with the highest plant height (111.0 cm), number of leaves (8.6 leaves/plant), leaf area (234.7 cm²/leaf), total biomass (6.8 g DM/plant), chlorophyll (47.3 SPAD readings), and absolute growth rate (0.103 g DM/day). Heavy metal content in roots, stems, and leaves of forage sorghum was found to increase significantly with increasing poultry manure amendment rate. The correlation analysis also showed that soil properties were strongly correlated with heavy metal forage sorghum. Bioaccumulation and translocator factor studies showed that forage sorghum had a high potential for heavy metal accumulation as indicated by values greater than 1. Although poultry manure can improve soil fertility and support forage sorghum growth, its use poses a risk due to the potential accumulation of heavy metals in the crop. Therefore, it should be applied with caution, and heavy metal levels in crops must be rigorously monitored to mitigate potential health risks.