A simple methodology to estimate plant volume in nitrous oxide emission studies.

Closed-chamber methodology is widely used for the estimation of greenhouse gas (GHG) emissions in agricultural systems. The volume displaced by plants inside chambers influences GHG flux estimation, although generally it is not discounted from chamber headspace in the calculation. A novel image analysis-based procedure is proposed to estimate plant volume and to assess its impact on nitrous oxide (N O) flux estimations in a wheat (Triticum aestivum L. 'Rimbaud') crop. A maximum of 2.2% of the 13-L chambers was displaced by plants, leading to a systematic 0.9% overestimation in cumulative N O emissions if plant volume was not considered. Thus, plant canopy volume should be taken into account for improving the accuracy of emissions.