The relevance of soil structure conservation and carbon sequestration in Chilean volcanic ash soils for achieving sustainable development goals

The concern about both soil degradation and the sustainable development goals (SDGs) Agenda has to be globally faced, considering the particularities of each country. This is especially true for Chilean soils, because an important part of agricultural and forestry activities are carried out on Andisols, which have high carbon storage capacity, and very low bulk density values. If we compare Andisols properties with those ones of non-volcanic soils we need to define more site-specific strategies to reach the SDGs on volcanic soils. The aim of this review is to highlight how the conservation of soil structure and carbon sequestration of Chilean Andisols can play an important role to achieve the SDGs. An increase in the bulk density from 0.3 to 0.9 Mg m(-3) in volcanic ash soils leads to soil compaction problems due to their low air capacity and air conductivity values. Therefore, adequate critical values of physical properties have to be considered to assess the impact of tillage management. Management practices that allow soil structure conservation are relevant to reach SDGs in volcanic ash soils. While the huge carbon storage capacity of these soils contributes to mitigate of the impact of climate change, the soil structure conservation can increase the water and nutrient accessibility by plants roots. Therefore, the conservation of the structure of these soils can be relevant to improve water use efficiency in agricultural systems. Finally, it is well-known that volcanic ash soils accumulate huge amounts of organic matter, however, more research is needed in order to: i) understand the consequences of carbon stabilization on soil structure dependent properties and soil resilience and support the hypothesis that non-tilled grasslands are capable to storage more C mass than tilled ones. To answer these questions long-term research is needed.