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We investigated various soil and climate properties that influence soil organic carbon (SOC) concentrations in sub-Saharan Africa. Our findings indicate that climate and geochemistry are equally important for explaining SOC variations. The key SOC-controlling factors are broadly similar to those for temperate regions, despite differences in soil development history between the two regions.

This paper focuses on the production of global maps of soil properties with quantified spatial uncertainty, as implemented in the SoilGrids version 2.0 product using DSM practices and adapting them for global digital soil mapping with legacy data. The quantitative evaluation showed metrics in line with previous studies. The qualitative evaluation showed that coarse-scale patterns are well reproduced. The spatial uncertainty at global scale highlighted the need for more soil observations.

Understanding how the rate of oxygen isotope exchange between water and CO₂ varies in soils is key for using the oxygen isotope composition of atmospheric CO₂ as a tracer of biosphere CO₂ fluxes at large scales. Across 44 diverse soils the rate of this exchange responded to pH, nitrate and microbial biomass, which are hypothesised to alter activity of the enzyme carbonic anhydrase in soils. Using these three soil traits, it is now possible to predict how this isotopic exchange varies spatially.

Global significance of metals (extractable Fe and Al phases) to control organic matter (OM) in recognized. Next key questions include the identification of their localization and mechanism behind OM–metal relationships. Across 23 soils of contrasting mineralogy, Fe and Al phases were mainly associated with microbially processed OM as meso-density microaggregates. OM- and metal-rich nanocomposites with a narrow OM :  metal ratio likely acted as binding agents. A new conceptual model was proposed.

Humanity depends on the existence of healthy soils, both for the production of food and for ensuring a healthy, biodiverse environment. In the face of global crises like the COVID-19 pandemic, a sustainable soil management strategy is essential to ensure food security based on more diverse, locally oriented, and resilient food production systems through improving access to land, sound land use planning, sustainable soil management, enhanced research, and investment in education and extension.

The goal of this study was to discuss current methods to create soils adapted for various green infrastructure (GI) designs. Investigating these new soils for several design categories of GI will provide technical information for management and design agencies. Moreover, these studies can serve as pioneer experiments to prevent recurring errors and, thus, provide improved plant growth practices. Results show that these constructed soils have a high potential to provide multiple soil functions.

Soils contain one of the largest and most dynamic pools of carbon on Earth, yet scientists still struggle to understand the reactivity and fate of soil organic matter upon disturbance. In this study, we found that with increasing thermal stability, the turnover time of organic matter increased from decades to centuries with a concurrent shift in chemical composition. In this proof-of-concept study, we found that ramped thermal analyses can provide new insights for understanding soil carbon.

The use of non-invasive geophysical imaging of root system processes is of increasing interest to study soil–plant interactions. The experiment focused on the behaviour of grapevine plants during a controlled infiltration experiment. The combination of the mise-à-la-masse (MALM) method, a variation of the classical electrical tomography map (ERT), for which the current is transmitted directly into the stem, holds the promise of being able to image root distribution.

Amazon soils hold as much carbon (C) as is contained in the vegetation. In this work we sampled soils across 8 different Amazonian countries to try to understand which soil properties control current Amazonian soil C concentrations. We confirm previous knowledge that highly developed soils hold C through clay content interactions but also show a previously unreported mechanism of soil C stabilization in the younger Amazonian soil types which hold C through aluminium organic matter interactions.

The application of machine learning (ML) has shown an accelerated adoption in soil sciences. It is a difficult task to manually review all papers on the application of ML. This paper aims to provide a review of the application of ML aided by topic modelling in order to find patterns in a large collection of publications. The objective is to gain insight into the applications and to discuss research gaps. We found 12 main topics and that ML methods usually perform better than traditional ones.

Soil quality depends on the functioning of soil microbiota. Only a few standardized methods are available to assess this as well as adverse effects of human activities. So we need to identify promising additional methods that target soil microbial function. Discussed are (i) molecular methods using qPCR for new endpoints, e.g. in N and P cycling and greenhouse gas emissions, (ii) techniques for fungal enzyme activities, and (iii) field methods on carbon turnover such as the litter bag test.

The Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident in March 2011 resulted in the contamination of Japanese landscapes with radioactive fallout. The objective of this review is to provide an overview of the decontamination strategies and their potential effectiveness in Japan. Overall, we believe it is important to synthesise the remediation lessons learnt following the FDNPP nuclear accident, which could be fundamental if radioactive fallout occurred somewhere on Earth in the future.

This study is restricted to soil physical aspects of soil quality and health with the objective to define procedures with worldwide rather than only regional applicability, reflecting modern developments in soil physical research and focusing on important questions regarding possible effects of soil degradation and climate change.

Land degradation impacts the health and livelihoods of about 1.5 billion people worldwide. The state of the environment and food security are strongly interlinked in tropical landscapes. This paper demonstrates the integration of soil organic carbon (SOC) and land health maps with socioeconomic datasets into an online, open-access platform called the Resilience Diagnostic and Decision Support Tool for Turkana County in Kenya.

This paper deals with the importance of soil for our terrestrial environment and the need to predict the impact of soil management on the multitude of functions that soil provides. We suggest to consider soil as a self-organized complex system and provide a concept of how this could be achieved. This includes how soil research, currently fragmented into a number of more or less disjunct disciplines, may be integrated to substantially contribute to a science-based evaluation of soil functions.

We discuss pathways towards better soil protection in the 21st century. The efficacy of soil conservation technology is not a fundamental barrier for a more sustainable soil management. However, soil conservation is generally not directly beneficial to the farmer. We believe that the solution of this conundrum is a rapid, smart intensification of agriculture in the Global South. This will reduce the financial burden and will, at the same time, allow more effective conservation.

For this study we systematically investigated the molecular pattern of leaf waxes in litter and topsoils along a European transect to assess their potential for palaeoenvironmental reconstruction. Our results show that leaf wax patterns depend on the type of vegetation. The vegetation signal is not only found in the litter; it can also be preserved to some degree in the topsoil.

Soil records provide information about 5 millennia of heath management in cultural landscapes on sandy soils. Deforestations and the introduction of the deep, stable economy in the 18th century resulted in sand drifting and heath degradation. After the introduction of chemical fertilizers more than 90 % of the heaths were transformed into productive arable field or forests. Currently the last heaths are preserved as part of the cultural heritage.

The Intergovernmental Technical Panel on Soils has completed the first State of the World's Soil Resources Report. The gravest threats were identified for all the regions of the world. This assessment forms a basis for future soil monitoring. The quality of soil information available for policy formulation must be improved.

The huge carbon stocks found in soils of the permafrost region are important to the global climate system because of their potential to decompose and release greenhouse gases into the atmosphere upon thawing. This review highlights permafrost characteristics, the influence of cryogenic processes on soil formation, organic carbon accumulation and distribution in permafrost soils, the vulnerability of this carbon upon permafrost thaw, and the role of permafrost soils in a changing climate.

Since seeds are the principle means by which plants move across the landscape, the final fate of seeds plays a fundamental role in the origin, maintenance, functioning and dynamics of plant communities. In arid and semiarid patchy ecosystems, where seeds are scattered into a heterogeneous environment and intense rainfalls occur, the transport of seeds by runoff to new sites represents an opportunity for seeds to reach more favourable sites for seed germination and seedling survival.

This paper provides a brief accounting of some of the many ways that the study of soils can be interdisciplinary, therefore giving examples of the types of papers we hope to see submitted to SOIL.