Effects of Altitude, Slope Aspect, and Soil Depth on Soil Properties and Herbaceous Root Distribution in Honghe Hani Rice Terraces

Research reveals that soil physical properties and nutrient contents in the Yuanyang Hani Terrace system exhibit distinct patterns influenced by altitude, slope aspect, and soil depth. Soil bulk density follows a unimodal trend along elevation gradients, with mid-elevations showing optimal conditions for porosity and infiltration rates, while high elevations present the poorest conditions. Shady slopes generally outperform sunny slopes, particularly at mid-elevations, where aspect-induced differences in bulk density are most pronounced. An unusual combination of high bulk density with peak porosity and infiltration rates was observed in the 20–40 cm soil layer, attributed to compaction-induced pore configuration changes that preserve preferential flow pathways. Nutrient levels vary significantly, with total potassium and available phosphorus peaking at low elevations due to chemical weathering intensity and plant uptake competition. Root systems are predominantly concentrated in the surface layer (0–20 cm), showing strong positive correlations with soil moisture and porosity, and negative correlations with bulk density. Principal component analysis indicates that physical hydrological processes are the primary drivers of environmental differentiation, explaining 73.4% of the variance. These findings provide a theoretical basis for sustainable management of terrace agroecosystems.

Huang, L., Zhang, X., Wang, X., Wang, R., Wang, R., Zhang, X., & Sun, Y. (2026). Effects of Altitude, Slope Aspect, and Soil Depth on Soil Properties and Herbaceous Root Distribution in Honghe Hani Rice Terraces. Plants, 15(14), 2144. https://doi.org/10.3390/plants15142144