In 2020, the Natural Capital Committee stated that available data suggest the state of soils in the UK is declining and a national survey is needed on the extent and condition of soils. Without national monitoring of soil organic carbon, structure and biodiversity, it will be difficult to assess the status of the range of benefits supporting human well-being provided by soil. These include growing food, carbon storage, water quality and reducing flood risk. Good stewardship of soils could increase the provision of these benefits. Most arable soils have lost 40–60% of their organic carbon, 2 million hectares of soil are at risk of erosion and 4 million hectares at risk of compaction. Erosion is the process by which top-soil is carried away by wind and water, which is accelerated by activities such as removal of vegetative cover, ploughing down sloping fields and overgrazing. Erosion is directly linked to the loss of soil carbon, which may have been stable for millennia.

Poor soil management can damage soil structure, which is not improved by shallow rooted crops that rely on fertilisers. For example, adding nitrogen to soil over long time periods changes plant and microbe interactions, decreasing diversity. In contrast, deep rooted crops and higher biodiversity grassland can increase fine roots, which bind soils and improve soil structure, as can crop diversification. Promoting a soil microbiome for higher plant productivity requires management of microbial and plant communities, and the processes they support, but varies greatly between soils.

This POSTnote will summarise the evidence base for measures such as no till, biochar and crop diversification and assessing the outcomes of their implementation, including whether they maintain carbon storage and resilience to the impacts of climate change on soils and plant productivity.

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