Agricultural Problem Soils

The term agricultural problem soil is not an exact determined concept and creates some inherent problems of definition.  Each soil type is a specific formation by the interaction of parent material, climate, organisms, topography and time.  The deriving soil properties have consequences for the use by man.  The possible types of agricultural use of a given soil may vary considerably.  Pasture, agroforestry and arable land use have different demands of favourable soil properties.  Moreover, different crops may demand very differing soil characteristics for optimal production.  This implies that the same soil may be considered for one production system as problematic and for another not.  Therefore the term "problem soil" always has to be seen together with the envisaged or practised land use system and the classification of different problem soils will always depend on the envisaged or given land use.  Thus, a “problem soil” is always related to a specific land use situation.  However, there are soil types with specific common characteristics that dominate frequently agricultural land use. These soil types may be broadly classified into problem soil categories.

Different types of agricultural problem soils have been selected for consideration within ProSoil:

• Acid soils (with and without aluminium toxicity, acid sulphate soils)

• Calcareous soils

• Histosols (peat soils)

• Salt-affected soils (saline and sodic soils)

• Sandy soils

• Steeplands 

• Vertisols

The selection reveals another difficulty:  the overlapping of different categories.  For instant, a histosol may be in many cases also characterized by acidity, thus being an acid soil, a vertisol may be salt-affected or soils of steeplands may be calcareous, etc.  Therefore, every time a judgement of the dominating problematic factor has to be made when agricultural problem soils are discussed.  The result of the judgement will be crucial for the classification of a given problem soil.

Further clarification and guidance is given by the classification system of problem soils which has been adopted by the Asian Network on Problem Soils in 1989.

Classification system for problem soils of the Asian Network on Problem Soils

For more information on diagnostic horizons of agricultural problem soils see the Horizon Glossary.