Soil Capability: Exploring the Functional Potentials of Different Soils.

Soil Capability: exploring the functional potentials of different soils.

J.Bouma

em.prof soil science, Wageningen University, the Netherlands,.

Soil capability has been defined as :”its potential functionality” or, more simply, “what can this soil do?”. Capability starts with considering seven soil functions: (i)biomass production; (ii) filtering and transforming compounds; (iii) biodiversity pool, (iv)cultural environment; (v)source raw materials; (vi) carbon pool and (vii) archive archeological and geological heritage.  Soil Taxonomy, based on permanent soil characteristics, can define the basic soil unit being considered ( the genoform), preferably at soil series level. Two aspects are considered when defining soil capability for any given soil by assessing: (1)  potential conditions, and (2) how and if potential conditions can be realized in practice. Ad (1):For each of the soil functions, actual conditions are assessed and the potential for improvement is explored by: (i) simulation modelling, considering different types of management and effects of climate change, and/or: (ii) identifying a typical range of phenoforms in the field and their relation with past land use. Ad (2) soil vulnerability and resilience are considered in a socio-economic context. The functions for any given soil should not be considered in isolation but in relation to one another , optimising each one with the objective to contribute as much as possible to address the major environmental challenges of food security, water shortage, biodiversity loss,  and climate change as part of the UN Sustainable Development Goals.  Expressing relations between the factors as a narrative can be quite helpful for communication purposes. Human capability has been developed in economic sciences by Amartya Sen and Martha Nussbaum and their concepts, that have evolved into the widely cited Human Development Index of the United Nations, can also be applied to develop a Soil Capability Index, (SCI) allowing increased soil exposure to the policy arena. The SCI would express for each function the ratio between what is actually achieved, versus what is theoretically possible at any given location thus indicating the length of the road to be travelled. When multiplied by 100, a value between 0 and 100 is obtained. Every soil has a different story to tell as potentials, vulnerabilities and resiliences vary widely. Soil Capability can only be realized when land users actively pursue innovative management, requiring close interaction with researchers in  a joint learning mode.