In order that the phosphoric acid may be the more fully liberated by the humic acid, &c., of the earth, a little silicious sand is mixed with the still molten slag after it has been poured off from the molten steel.
It contains considerable humic matter, discolouring rapidly in the air (when exposed it is characteristically a bright buff).
Humic type of coal that is predominantly composed of mixed plant debris.
The stream bottoms of alluvium are modified by loess and humic deposits, and are of course very fertile; but hardly more so than the loess of the uplands.