Table 1 Correlation between soil-test K extracted with 1.0 mol L−1 NH4OAc, 2.0 mol L−1 cold HNO3, 0.2 mol L−1 NaTPB and 1.0 mol L−1 boiling HNO3 solution.
From: Establishing grading indices of available soil potassium on paddy soils in Hubei province, China
NH4OAc-K | Cold HNO3-K | NaTPB-K | Boiling HNO3-K | |
|---|---|---|---|---|
NH4OAc-K | — | — | — | — |
Cold HNO3-K | 0.957** | — | — | — |
NaTPB-K | 0.817** | 0.848** | — | — |
Boiling HNO3-K | 0.584** | 0.678** | 0.639** | — |
