Measurements of N2O and NO emissions during tomato cultivation using a flow-through chamber system in a glasshouse

Abstract

Nitrous oxide (N2O) and nitric oxide (NO) fluxes resulting from long-term tomato cultivation in a glasshouse were continuously determined using the flow-through chamber method over the course of three cultivation periods. Gas concentrations were measured using an nondispersive infrared (gas filter correlation/infra-red) analyzer and a chemiluminescence-based analyzer, respectively. Following a basal application of fertilizer, daily N2O and NO emission rates increased, with peaks lasting from 40 to 140 days. Short-term fluctuations in daily N2O and NO emissions were affected by differences in nitrogen application, soil water, and soil temperature. Diurnal changes in N2O and NO fluxes during the period of peak emissions depended primarily on soil temperature. Following the application of a top dressing (N as urea or calcium nitrate) in the irrigation water, the N2O and NO fluxes increased immediately, with a very short period of peak emissions (1–5 h) after urea application. The duration of the peak period in daily accumulated N2O and NO emissions following application of the top dressing ranged from 3 to 10 days.