Relative entropy as an index of soil structure

Soil structure controls key soil functions in both natural and agro-ecosystems. Thus, numerous attempts have been made to develop methods aiming at its characterization. Here we propose an index of that uses relative entropy quantify differences the porosity pore(void)-size distribution (VSD) between a structured derived from water retention data same without (a so-called reference soil) estimated particle-size (PSD). The difference these VSDs, which is result structure, quantified using Kullback–Leibler Divergence (KL divergence). We applied method two Swedish field experiments investigate long-term effects management (fallow vs. inorganic fertilizer manure) land use (afforested agricultural dominated by grass/clover ley) on properties. KL divergence was larger for receiving regular addition manure compared with soils no organic amendments. Furthermore, under afforested showed significantly divergences near surface, but smaller deeper layers, closely mirrored matter profile. Indeed, significant positive correlation (r = 0.374, p < 0.001) found carbon concentrations across all sites treatments. Despite challenges related modelling VSD proposed proved useful evaluating response land-use change reflected expected structure. conclude shows great potential serve as easy-to-use it only requires widely available physical hydraulic Highlights A new based developed separates texture pore space identified structural (SOC) metric