A sampling technique for the determination of dissolved methane in soil solution

A sampling technique was developed to sample floodwater and soil solution from wetland ricefields for the determination of dissolved CH₄. The method was compared with the soil core method used in the measurement of entrapped CH₄. This was done to assess if dissolved CH₄ determination could be an alternative to soil-entrapped CH₄ measurements since the latter is time-consuming, laborious and destructive in nature.

The dynamics of both dissolved CH₄ and entrapped CH₄ follow the same seasonal pattern. They have the same degree of spatial and temporal variability. However, the sampling procedure developed for the determination of dissolved CH₄ is relatively simple, easy and convenient compared to that for soil-entrapped CH₄ measurements. It also allows in-situ solution sampling at different soil depths. Therefore, it is recommended that dissolved CH₄ measurements can be an alternative to soil-entrapped CH₄ determinations.