SOIL HEALTH AS A CONCEPT TO ENHANCE SOIL STEWARDSHIP AND LAND USE POLICIES

Soil health can be defined as : The actual capacity of a particular type of soil to function, contributing to realizing the U.N. Sustainable Development Goals (SDG) and the EU Green Deal (GD). Soils are seen as contributing to a set of interdisciplinary ecosystem services (ES) that, in turn, contribute to SDGs and the GD. Important ES consist of: (i) biomass production; (ii) ground- and surfacewater quality protection, (iii) carbon capture, (iv) reduction of greenhouse gas emissions and: (v) enhancement of biodiversity. Quantitative assessment of soil health is still not possible. A method is proposed based on indicators,defining a favorable root environment and soil health (SH) is defined by applying modeling associated with the agronomic concept of the ":yield-gap" defining (Ya/Yw) x 100, as a quantitative indicator for soil health, where Ya is actual yield and Yw is water-limited yield , the latter assuming sufficient nutrients and lack of pests and deseases. This single number is useful for communication purposes of SH to farmers, the policy arena and the public, indicating the actual status and possible room for improvement. This relates to ES biomass production; the other four have to be achieved by appropriate management, where good soil health can provide a significant contribution. Assessment of SH values will be presented for an Italian case study also incorporating possible effects of climate change by modeling. Subsidy programs could be based on realizing other ES than biomass production if farmers cannot finance necessary environmental measures. To avoid the risk that soil health, thus defined, will be yet another top-down procedure that is not internalised nor applied by actual and potential users of soil information, a start with defining "lighthouses" is proposed which are successful farms where somehow the five ecosystem services are being delivered by adaptive management as evidenced by on-site measurements using a new range of innovative proximal and remote sensing monitoring techniques. By showing such bottom-up examples on internet, other farmers may adopt certain practices, improving their stewardship of the soil . Monitoring will show gaps in knowledge to be closed with new research, the best way to define the latter. .