Semicontinuous Measurement of Soil Atmosphere Gases with Gas‐Flow Soil Core Method

Abstract

Abstract To study denitrification, a method was developed for simultaneous measurement of CO 2 , N 2 , N 2 O, and NO production in soil cores. The technique does not interfere with biochemical processes in the soil and is fully automated to enable highly time‐resolved measurements for prolonged periods. Soil cores (intact or repacked) are connected to individual gas‐tight circuits (up to nine). Gas is continuously circulated through the soil cores to avoid diffusional problems. Each individual circuit can be automatically sampled for chromatographic gas analysis. The N 2 O production rates can be measured accurately down to 0.04 µg N kg −1 measuring interval −1 (MI). Determination of N 2 , CO 2 , and O 2 production rates is less sensitive: 0.09 mg N kg −1 MI −1 , 0.04 mg C kg −1 MI −1 , and 0.02 mg O kg −1 MI −1 , respectively. Dynamically changing gas production rates are monitored accurately, and total N gas production under anaerobiosis is balanced by NO 3 − disappearance.