Soil-Gas Diffusivity-Based Characterization of Variably Saturated Agricultural Topsoils

Soil-gas diffusivity and its variation with soil moisture plays a fundamental role in diffusion-controlled migration of climate-impact gases from different terrestrial agroecosystems including cultivated soils managed pasture systems. The wide contrast texture structure (e.g., density, aggregation) agriculture topsoils (0–10 cm) makes it challenging for soil-gas predictive models to make accurate predictions across conditions. This study characterized gas gas-phase tortuosity sampled sites Sri Lanka at 0–10 cm depth, together selected data the literature. was measured using one-chamber diffusion apparatus N2 O2 as experimental gases. diffusivity, literature representing both intact repacked soils, were tested against five existing widely known models. tended mischaracterize two-region behavior some aggregated suggesting need soil-specific better describe agricultural soils. We suggested new parametric model, developed line literature-based models, represent unimodal bimodal/two-region model statistically outperformed and, hence, demonstrated applicability characterize site-specific greenhouse emissions under water regimes.