Several models predict soil pore space indices (the relative gas diffusion coefficient, Ds/Do and the pore tortuosity, t), but information is lacking on which models predicted indices better relate to soil processes. We compared pore space indices′ predictive models based on air-filled porosity (fa) alone vs. models using air-filled porosity and total pore space (Φ) (fa Φ). We also assessed the relationships between these indices and CO2 and N2O. The study was conducted from 2011 to 2014 on a silt loam soil at Lincoln University. Soil samples were collected at 0-10 and 10-20 cm depth and oven dried at 105 °C for 72 h. After drying, fa and Φ were calculated and later used in models for predicting Ds/Do and t. CO2 and N2O were measured with a Shimadzu gas chromatograph (GC) and a photoacoustic gas analyzer (PSA). Results showed that Ds/Do predicted using fa alone (Marshall and Buckingham) was higher as compared with values predicted with models based on fa Φ (Sallam et al., Millington, and Jin and Jury) (P < 0.001). However, values of t predicted with models based on fa alone were lowest (P < 0.001). CO2 and N2O measured with GC better related with Ds/Do and t.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 96 • No. 3