Field-Scale Yield of Switchgrass Under Varying Nitrogen Management Treatments In New York State.

Cornell University, in New York State,  is one of several locations nationwide hosting a switchgrass production trial as part of a Regional Herbaceous Feedstock Partnership sponsored by the North Central Center Region SunGrant Initiative and the U. S. Department of Energy Biomass Program. The objectives of these trials are to gather biomass yield and sustainability data on a field-scale to assess potential expansion of switchgrass as a bioenergy feedstock resource. The 12 acre field trial at Cornell was established in a randomized complete block design with four replications (approximately 1 acre per replicate). The switchgrass upland cultivar ‘Cave-in-rock’ was planted 29 May 2008 at 7.3 kg bulk seed equivalent to 11.2 kg pure live seed/ha.  Soil samples were collected at nine locations and at 4 depths, 0-5 cm; 5-15 cm; 15-30 cm; 30-60 cm, on 22 April 2008 prior to plowing. Nitrogen (N) fertilizer treatments (0, 56 and 112 kg/ha) applied as ammonium sulfate were made on 20 May 2009 and 4 June 2010. Switchgrass was harvested on 22 October 2009 and 4 November 2010. No significant yield response to nitrogen application was observed in 2009. In 2010, the no N treatment had significantly higher yield than did the highest N treated plots. Average yield was 10.4 Mg/ha for the no N treatment versus 8.8 Mg/ha for the highest N treatment (112 kg/ha) in 2010.  Canopy height, measured at harvest, was also significantly higher in 2010 in the no N treated plots than the high N treatment. Soil organic matter has increased over time in the entire field planted to switchgrass.