Industry, sector and description for Universal Display. Universal Display researches, develops, and sells organic light emitting diode (OLED) technologies and materials for the flat-panel display industry.
The first requirement for all master horizons other than O horizons is that they are composed mostly of mineral material. It is very important to be able to differentiate organic from mineral material. Dark color of the A horizon is due to the mixing of humus with mineral.
The A horizon is the topmost layer of the mineral soil. As it lies just below the O horizon, this layer also has some amount of humus in it and therefore, it is darker than the layers below. Similarly, the soil particles in this zone are smaller and finer compared to the lower horizons of the soil.