Original data for "High risk of soil available silicon deficiency in bamboo forest: Insights from bamboo afforestation chronosequences in the karst region of southwest China"

Soil available silicon (ASi) is crucial for sustaining soil-plant Si cycle and ecological functioning in bamboo forests. However, it still lacks a systematic understanding of how to quantify soil ASi in bamboo forest and to predict when these soils will face a Si deficiency risk. Herein, we studied soil ASi dynamics and aboveground Si accumulation across a chronosequence of bamboo stands (0, 5, 10, 20, 40, and 100 years old). By comparing the variation of five soil ASi proxies, we found that 0.01 M CaCl2 extractable Si (CaCl2-Si, 5.05–26.72 mg kg–1) and water extractable Si (H2O-Si, 4.20–19.89mg kg–1) were the only two proxies that exhibited a consistent declining trend with increasing stand age across all soil layers. Given its practicality for large-scale analysis, we recommend CaCl2-Si as the optimal indicator for routine soil ASi assessment in bamboo forests. Furthermore, aboveground Si content decreased significantly from leaves (10.54–21.45 g kg–1) to branches (3.81–5.61 g kg–1) and culms (1.07–1.98 g kg–1). Both leaf Si and weighted Si content peaked at 5 years and then progressively declined, showing significant correlations with reliable soil ASi proxies (i.e., CaCl2-Si and H2O-Si). Preliminary estimation revealed that the annual soil ASi removal rate declined from 3 g Si m⁻2 year⁻1 in the first 40 years post-afforestation to 2 g Si m⁻2 year⁻1 thereafter, due to progressive depletion of the soil ASi pool. Our integrated findings indicate that bamboo forests face soil ASi depletion within 10–40 years post-afforestation, primarily driven by biomass culm harvest. Therefore, Si fertilizer application is essential to sustain the long-term ecological and economic sustainability of bamboo forests.