Soils act as a natural climate solution due to their large capacity for carbon storage. This study identifies cost-effective strategies that encourage soil carbon inventories to expand their focus into urban environments. To achieve carbon neutrality, urban planners should strive to identify areas that can be utilised for green spaces and conservation.

Physical protection stabilises organic matter in most mineral soils, but whether this occurs via a hierarchy of aggregate particles or by build-up of organo–mineral associations, remains obscure, especially in tropical forest environments. Here we investigate by comparing soils with contrasting parent material, topography, and pedogenesis, but with similar tropical moist forest. The comparative approach identified clay mineralogy as an important control on physically protected soil organic matter and pointed to the aggregate hierarchy route.

The increased demand for food and global population growth urgently requires cultivation of a larger area of salinised soil. The paddy–upland rotation system has substantial influence on the sustainability of soil quality and microbial diversity. This research provides a sustainable and resource-saving management model for saline-alkali land, especially in arid and arid regions.

Adequate decision making requires soil sampling followed by several costly and non-environmentally friendly laboratory analyses. However, proximal sensors have delivered promising results to accelerate and reduce the costs of this process. This study showed that pXRF could accurately predict the results of USEPA 3051a analysis (a standard method for tropical soils characterisation), using machine learning algorithms, at reduced costs and time, which is drastically important for developing countries, where lack of financial resources for detailed soil characterisation and environmental assessment is common.