Investigation of desert subsoil nitrate in Northeastern Badia of Jordan.

High levels of naturally occurring nitrate were observed under desert pavement surfaces in NE Badia of Jordan. The subsoil nitrate inventory varies from about 24,351 to 28,853 kg NO(3)(-)/ha to a depth of 60 cm which is more than two times greater than nitrate in nonpavement soils, although both soils occurred within similar landscape and microclimate conditions. The results indicated that pavement particle size and cover percent are the primary factors contributing to the observed variations in nitrate accumulation. Desert pavement soils fully covered with fine clasts showed higher nitrate concentrations compared to soils moderately covered with coarse-grained pavements. The results also showed that high levels of nitrate were generally reached between 20 and 30 cm depth before the concentrations decreased. Chloride showed distribution profiles similar to those of nitrate. No observable difference was observed in nitrate level under desert pavement with abundant lichens compared to non-lichen pavement surface.