Evaluation of Torrefied Napiergrass (Pennisetum purpureum Schumach.) Biomass As a Renewable Fertilizer.

The development of designer, biochar-based fertilizers from perennial, high-biomass feedstocks provides immense opportunity to offset chemical fertilizers. While fertilization is vital for food, feed, fiber, and fuel production, excessive application and loss (volatilization, leaching, run-off, etc.) of inorganic fertilizers have significant, detrimental environmental impacts. This trend has increased dramatically with modern, intensive agricultural practices. Increasing prices for petroleum-based and mined fertilizers further limit opportunities for their utilization in developing nations. As a potential alternative, this study converted a high-nitrogen-feedstock into an organic, pyrolysis-based, biomass-derived, renewable fertilizer. Napiergrass, Pennisetum purpureum Schumach., (cv. Merkeron) produces high dry matter yields (20-30 dta/y) and contains high crude protein content (15-20% dwt). It can be harvested multiple times a year and requires little to no supplemental nutrition. Torrefaction of napiergrass biomass was carried out under atmospheric pressure and in the absence of oxygen. The resulting ‘Torrified Biomass Fertilizer’ (TBF) was ground to a 2mm particle size and compared to inorganic fertilizer for yield response in maize and pearl millet-napiergrass hybrids. Results of the study will be discussed.