EFFECT OF NITROGEN FERTILIZER ON NITROUS OXIDE EMISSIONS FROM THE SOIL FOR TWO POTENTIAL ENERGY CROPS AND THE RELATIVE GREENHOUSE GAS EMISSIONS

Abstract

The benefits from energy crops are debated. This two-year study was designed to investigate nitrous oxide (N2O) emissions, yield and ash content from fertilized bioenergy crops switchgrass and reed canary grass with and without inter-seeded red clover. Overall, N2O emissions were less than 1kg N2O-N ha-1 in the first year and around 100g N2O-N ha-1 in the second year with a N fertilizer effect in the first year. Plots inter-seeded with red clover received half the N fertilizer of pure grass stands but showed no difference in N2O emissions compared to the pure stands and also had higher ash content. Cumulative soil mineral N responded to N fertilizer addition but no effect of crop type was evident in 2008 and 2009. Yields for both crops were unresponsive to N fertilizer addition while pure switchgrass yielded higher than inter-seeded switchgrass in 2008 and switchgrass had lower ash content.