If the climate in an area has very little rainfall, what would be the characteristics of the soil in the area?

The answer is thin, with very little organic material. The reason the soils are thin is that weathering of rocks in such regions is slow due to lack of rainfall. Water is a significant factor in weathering. Additionally, due to the dryness, little vegetation and organisms will thrive. Therefore, chemical weathering of the rocks will be reduced and the humus (organic material) in the soil will be less abundant.