Weathered coal seams (blooms) commonly occur at depths <150 cm under benches on steep slopes in eastern Kentucky. Since blooms are within the reach of tree roots and are C‐rich, they may affect nutrient availability and tree growth. This study was conducted to characterize the properties of blooms, and to examine growth and nutrient uptake by trees grown on blooms in the greenhouse. Samples were collected from eight profiles and properties of blooms were compared with those of overlying A horizons. Blooms occurred at a median depth of 68 cm and were generally loamy; coarse‐fraction concentrations were <100 g/kg, and bulk densities ranged from 0.56 to 1.25 Mg/m 3 . Compared with overlying A horizons, blooms had higher C (median values, 216 vs. 37 g/kg), total N (4.0 vs. 1.9 g/kg), and C/N ratios (48 vs. 21), and lower Ca (0.2 vs. 0.8 cmol c /kg), P (1 × 10 −3 vs. 7 × 10 −3 g/kg), and mineralizable N (8 × 10 −3 vs. 50 × 10 −3 g/kg). Available water capacity of disturbed samples (range 0.13–0.32 m 3 /m 3 ) and pH (3.4–5.0) were similar for blooms and A horizons. Root densities were much greater in A horizons, but densities in blooms were greater than predicted for horizons formed at the same depth in colluvium. Yields and nutrient concentrations of yellow poplar ( Liriodendron tulipifera L.) grown in the greenhouse on blooms were low, probably due to a shortage of available N. Blooms are of low fertility and apparently do not affect forest composition under natural conditions.
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Sainju et al. (1990) studied this question.