Biomass yield and feedstock quality of prairie cordgrass in response to seeding rate, row spacing, and nitrogen fertilization

Prairie cordgrass (Spartina pectinata Link) shows potential as a bioenergy feedstock in marginal croplands across much of the United States and Canada. Objectives of this study were to: (i) evaluate the effects of seeding rate and row spacing on biomass yield and (ii) determine effects of N fertilization on biomass yield and feedstock quality of prairie cordgrass. During 2012, a field trial composed of three seeding rates (162, 323, and 484 pure live seed [PLS] m^–2) and three row spacing treatments (19, 38, and 76 cm) was established in Urbana, IL. In the same year, another field trial was established with four N rates (0, 84, 168, and 84/84 [equal split applications during spring and after V6 stage] kg N ha^–1). During 2013 to 2016, no differences in biomass yields were observed under all combinations of seeding rate and row spacing treatment, except for a higher yield under 76-cm spacing in 2014. Biomass yields increased as N applications increased from 0 to 84 kg N ha^–1, but no additional response occurred above this rate. Feedstock quality (cellulose, hemicellulose, and ash concentrations) was not affected by N rate. Biomass nutrient removal increased as N fertilization caused an increase in biomass yield except for biomass P. Our results indicated that prairie cordgrass could be successfully established in 76-cm row spacing with a seeding rate of 162 PLS m^–2. The recommended N rate for maximum yield is 84 kg N ha^–1 based on a post-killing frost harvest.