Figures & data
Table 1. Yield, potassium (K) and silicon (Si) uptake and balance (annual and average) in forage rice cultivars
Figure 1. Temporal changes in aluminum and organic carbon contents of extracts from soils by a 5-step sequential procedure. (a) Al contents extracted by 0.5 M CuCl2 solution (AlCu) and 0.1 M Na-pyrophosphate solution (Alp). Alp in FRC-soil (r = 0.73, P = 0.011, Increase rate (Δ) = 57 mg Al kg−1 year-1), AlCu in FRC-soil (r = 0.83 P = 0.002, Δ = 16 mg Al kg−1 year−1), and AlCu in ERC-soil (r = 0.88, P = 0.001, Δ = 13 mg Al kg-1 year-1) increased linearly with time. (b) Organic carbon content extracted by 0.1 M Na-pyrophosphate solution (Cp). Cp in FRC-soil (r = 0.65 P = 0.029, Δ = 73 mg C kg-1 year-1) increased linearly with time
Table 2. Yield, potassium (K) and silicon (Si) uptake and balance (annual and average) in edible rice cultivars
Figure 2. Schematic chemical reaction of weathering process of primary minerals by root surface cell wall (CW) of plants and nutritional K and Si (a), or only K (b) are taken up by the plants. Solubilized active Al reacts with organic compounds to form persistent soil storage carbon
Table 3. Organic acids exuded from the roots of 5 plant species
Table 4. Elements released (K, Si, Al) by “contact reactions” between plant roots and soils or minerals (orthoclase, obsidian, kaolinite)
Appendix 1. Exchangeable potassium (K) and non-exchangeable K contents in FRC-soils
Appendix 2. Exchangeable potassium (K) and non-exchangeable K contents in ERC- soils
Appendix 3. Extractable aluminum contents by 5-sequential extraction in FRC- soils
Appendix 4. Extractable aluminum contents by 5-sequential extraction in ERC- soils