Vertical Distribution of Forest Soil Physicochemical Properties and Their Environmental Covariates in Maoming City, Southern Subtropical China
Year: 2026
Type: article
Abstract: Forest soil organic carbon (SOC) and nutrient dynamics are critical for terrestrial carbon cycling, yet full-profile soil property characterization at regional scale remains limited in southern subtropical China. Based on 0–100 cm soil profile data from 443 sampling points (6,645 records) in Maoming City, this study investigated vertical distribution patterns of SOC, total N, total P, total K, pH, and stoichiometric ratios, and quantified the relative contributions of stand type and topographic factors using linear mixed-effects models, random forest, and geostatistical kriging. SOC and total N exhibited pronounced surface accumulation, declining by approximately 50% and 44% from the surface (12.75 g/kg and 941 mg/kg) to the 80–100 cm layer (6.35 g/kg and 530 mg/kg), respectively. Total P showed minimal vertical variation (~5%), total K remained stable, and pH increased slightly with depth (4.55 → 4.66). Stand type significantly affected SOC, total N, total K, pH, and most stoichiometric ratios (all p < 0.05); broadleaf mixed and coniferous forests had higher surface SOC than eucalypt, economic, and litchi/longan plantations. All stoichiometric ratios decreased significantly with depth, indicating progressive organic matter decomposition. Random forest revealed that soil depth most strongly explained SOC and total N (permutation importance 0.44–0.60), stand type dominated pH and total K (0.40–0.48), and aspect notably influenced total K and N:K (0.23–0.34). All properties showed moderate spatial autocorrelation (nugget ratio 0.47–0.67). These findings provide regional evidence for 0–100 cm nutrient vertical patterns and a scientific basis for forest soil nutrient management and carbon sink assessment.
Source: Forests
DOI: 10.3390/f17111304
Institution: Guangdong Academy of Forestry
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $3,137
OpenAlex ID: W7212173636