Soil Restoration and Monitoring Guidelines

To make this context-dependency clear, we adopt the framework of McBratney et al. (2014, 2019) who introduces five key dimensions of soil value with capacity, referring to the soil's inherent potential, and condition, referring to the current state of soil health, as most important in the context of practical restoration. The other dimensions refer to capital, reflecting the economic worth of soils influenced by markets, productivity, and land ownership; connectivity, emphasizing the role of knowledge, resources, and interactions with environmental and social systems in maintaining soil health; and codification, involving the policies and knowledge systems that guide soil management, varying by region and culture, but are not used in the below described guidelines. Together, these dimensions highlight that effective and sustainable soil management depends on local context and a long-term approach (A. McBratney et al., 2014; Alex. B. McBratney et al., 2019). First, it is important to evaluate the inherent potential of certain sites and establish a baseline. Therefore we adopt the concept of soil capability that refers to the soil's inherent potential to perform specific functions such as supporting plant growth and ecosystem services, which varies with local climate, topography, and soil type. Capability is shaped by decades of land evaluation research and contains a set of long time-scale or very slowly changing characteristics. For example, soil texture greatly determines the potential of a certain site for forest ecosystem functioning as it affects overall soil fertility, water holding capacity, acid buffering capacity. Yet soil texture is not a variable that can be (easily) changed through management and is therefore a fixed boundary condition to understand a certain soil condition. Second, soil condition encompasses the latter, i.e. the manageable physical, chemical and biological soil properties to assess the current state of the soil, influenced by land use practices, pollution, and conservation efforts and is being assessed on a short-term management timescale. The condition of the soil refers to its ability to function within land use and ecosystem boundaries and will vary to how it is managed. A combination between condition and capability results in the productivity/performance of the soil. Effective monitoring can only be executed when both soil capability as soil condition are evaluated.