Assessing Gas Diffusion Coefficients in Growing Media from in situ Water Flow and Storage Measurements

摘要: Knowledge of gas exchange dynamics is important in determining the suitability growing media used nursery and greenhouse production. However, diffusion measurement methods are difficult to use directly potted a rapid, simpler, reliable approach appears desirable for routine assessment diffusivity. This study compares diffusivity pore efficiency estimates from chamber with indirect obtained water storage flow measurements point air entry values various substrates. Four peat substrates bark variable particle sizes, mineral soil, silica sand were packed into aluminum cores four replicates then saturated 72 h. After equilibration at −0.8 kPa potential on tension table, concentrations N2 diffusing through these measured calculated concentration change time. Diffusivity was also desorption curve hydraulic conductivity, same core (indirect approach). The by significantly correlated ( R 2 = 0.49, slope not different 1) those approach. Estimates much closer less than 0.80, 1). may be useful tool rapid under undisturbed conditions.