H_E-PQ Diagram of Soil Humus
1976 Volume 20 Issue 2 Pages 120-127
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1976 Volume 20 Issue 2 Pages 120-127
A H_E-PQ diagram for characterizing soil humus has been proposed. Here. H_E values mean the amount of 0.1N KMnO_4 in milliliter consumed by humic and fulvic acids contained in one gram of soil, while PQ values mean the percentage of humic acid in humic and fulvic acids. As for the A_0 and A horizons of soils dealt with in this paper, the following seven groups were differentiated on the diagram: 1. L, F H layers of all soils. 2. Alpine grassland soils. 3. Soils under temperate and subalpine forests. 4. Soils under warm-temperate forests. 5. Soils under tropical and subtropical forests. 6. Volcanic ash soils (Ohmasa's black soils). 7. Buried A horizons of volcanic ash soil. Podsols were characterized by the fact that each horizon was widely distributed on the diagram and grouping of their A horizons was impossible.
