The N-induced soil acidification has been a significant threat to species diversity and terrestrial ecosystem functioning. The most important causes of soil acidification on agricultural land are the application of ammonium-based fertilizers and urea, elemental S fertilizer, and the growth of legumes. The development of soil acidity essentially involves leaching of bases mainly calcium and magnesium under very high rainfall conditions. Soil pH affects crops in many ways and its effects are mostly indirect, through its influence on chemical factors and biological processes. The procedure for delineation and mapping of acid soils is similar to that used for mapping other soils. By virtue of providing 3D view of the terrain, aerial photographs have been used in soil surveys since the early 1930s. The aspect/element refers to the kind of objects or features on which a particular analysis is based. Physiographic analysis is based on a thorough knowledge of physiographic processes and their reflection on aerial photographs.