Stoichiometric Variation in Soil Carbon, Nitrogen, and Phosphorus Following Cropland Conversion to Forest in Southwest China

Soil organic carbon (SOC), nitrogen (N), and phosphorus (P) are three essential soil nutrients for plant growth, their stoichiometric ratios already important indices of elemental balance the fertility status in ecosystems. The evolution mechanism SOC, Total Nitrogen (TN), Phosphorus (TP), stoichiometry following “conversion cropland to forest program” (CCFP) southwest China is not yet clear. Seven different CCFP restoration models, including Zenia insignis (RD), Toona sinensis (XC), Castanea mollissima (BL), Citrus reticulate (GJ), Guimu-1 elephant grass (RG), (GM), abandoned (LH), were chosen explore changes concentration TN, TP, recovery times, at a depth 0–100 cm. results indicate that SOC TN concentrations models all increased with years topsoil, whereas TP remained relatively stable. C:N C:P increasing N: P ratio was stable over time. After ten reforestation, decreased as layer increased. effects model on C: N greater shallow soils. Our suggest complex reaction vegetation mode, particularly topsoil. This research further improves understanding N, interactions restricted nutrition, provides relevant theoretical support karst region.