Emission of N2O from rye grass (Lolium perenne L.)

The possibility of an additional N2O emission pathway via plants was investigated in a soil-ryegrass (Lolium perenne L.) system. The N2O emission rate of the system varied between 0.8 and 13.3 mg N2O-N m(-2) day(-1). Comparing the N2O emission rate of the system before and immediately after cutting the rye grass allowed us to calculate the contribution of the rye grass to the N2O emission from the soil-plant system. It was found that, depending on the type of fertilization and the growing period of the plants, the N2O released from the rye grass varied between 0 and 2.8 mg N2O-N m(-2) day(-1). N2O emission mediated by the rye grass increased towards the end of the growing period. An exponential correlation [R-2=0.93, y=(8x10(-6) x(2))-(2 x 10(-5) x)+0.21] was observed between the N2O emission (y) from the rye grass and its NO3--N content (x). However, it was not clear whether N2O was produced by the plants themselves or whether the rye grass served as a conduit for N2O produced in the soil.