Data from thousands of soil samples suggests that land management has a significant impact on soil organic matter (SOM) levels.
Overall, the less soil disturbance and less intensive farming practices tend to improve SOM levels over time, according to NRM's data.
The UK agricultural analysis business has been collecting soil analysis data since 1995, and has released the new data today (30 October).
For the first time, it has published consolidated, anonymised data on SOM gathered from over 11,000 samples analysed from June 2023 to May 2024.
It says this data will help farmers design and implement insightful management plans to help improve soil health and optimise crop production, whilst transitioning towards more sustainable practices.
One finding from the data was that, while the interquartile range for arable soils lies between 3.6% and 6.3%, showing relatively moderate SOM levels, grassland soils exhibit a significantly higher range of 7.3% to 12.9%.
Sajjad Awan, agronomy manager at NRM, said this really emphasised the impact of land use on SOM content.
"Adding organic inputs or disturbing your soil less can boost SOM levels, giving you a step up in terms of soil health," he said.
"The broader SOM range we found in grasslands is likely due to system factors such as cutting frequency, grazing intensity, and plant diversity.
"In contrast, the narrower SOM range found in arable soils suggests that, even though levels tend to be more uniform, intensive farming practices tend to reduce SOM over time.”
Whilst around 90% of arable farmers regularly book NRM's standard soil tests, only around 17% test for organic matter.
The firm says this gap is significant, as SOM influences everything from fertility and water retention to soil aeration, root penetration and bulk density.
And an up-to-date SOM analysis is vital to meet the requirements of the Sustainable Farming Incentive (SFI)’s SAM1 action for soils.
Mr Awan added: "By understanding and managing SOM levels alongside nutrient analysis, growers and advisors can make more insightful management decisions.
"Better decision-making leads to improved soil health and compliance with sustainability objectives, both of which help to bolster the resilience of farming businesses."
