Table 1.
Linear mixed-effects model results for soil properties, Cd/As availability, and metals in iron plaque.
| Variable | Water (W), F(1, 16) | Amendment (A), F(3, 16) | Stage (S), F(2, 32) | W×A, F(3, 16) | W×S, F(2, 32) | A×S, F(6, 32) | W×A×S, F(6, 32) |
|---|---|---|---|---|---|---|---|
| pH | 50.18*** | 69.18*** | 115.64*** | 5.11* | 4.74* | 19.43*** | 4.26** |
| Eh | 601.39*** | 11.38*** | 20.57*** | 1.88 ns | 138.24*** | 1.70 ns | 0.66 ns |
| CaCl2-Cd | 2,433.78*** | 292.96*** | 454.23*** | 182.28*** | 223.37*** | 109.80*** | 100.87*** |
| KH2PO4-As | 1,238.51*** | 32.42*** | 162.82*** | 29.77*** | 304.36*** | 9.37*** | 8.25*** |
| CdIP | 459.20*** | 38.42*** | 12.13*** | 20.04*** | 161.18*** | 13.24*** | 11.54*** |
| AsIP | 877.59*** | 30.69*** | 5,270.55*** | 230.95*** | 1,549.02*** | 100.02*** | 77.46*** |
| FeIP | 0.02 ns | 69.84*** | 359.79*** | 75.45*** | 63.82*** | 90.70*** | 55.85*** |
| CdIP/FeIP | 541.15*** | 4.98** | 117.90*** | 4.27** | 230.04*** | 13.79*** | 12.69*** |
| AsIP/FeIP | 266.97*** | 24.86*** | 220.77*** | 86.81*** | 115.45*** | 39.77*** | 25.42*** |
Values are F-statistics from the Type III tests of fixed effects. Numerator and denominator degrees of freedom are shown in the column headings. Pot identity was included as a random intercept. CdIP, AsIP, and FeIP indicate Cd, As, and Fe in iron plaque, respectively; ***p < 0.001, **p < 0.01, *p < 0.05, ns, not significant (p ≥ 0.05).