NRM has released data from thousands of soil samples, which 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.
NRM has been collecting soil analysis data since 1995. For the first time, the company has published consolidated, anonymised data on SOM gathered from over 11,000 samples analysed from June 2023 to May 2024. This data could help farmers design and implement insightful management plans to help improve soil health and optimise crop production whilst transitioning towards more sustainable agricultural practices.
“An interesting finding from our SOM 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%,” says Sajjad Awan, agronomy manager at NRM. “This emphasises the impact of land use on SOM content—adding organic inputs or disturbing the soil less can boost SOM levels.
“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.”
Very few farmers test for SOM
NRM data shows that although around 90% of arable farmers regularly book standard soil tests, only around 17% test for organic matter. “This gap is significant, as SOM influences everything from fertility and water retention to soil aeration, root penetration and bulk density. 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,” he adds
NRM’s SOM analysis can be easily added to its standard soil package. NRM’s standard soil package provides soil indices based on RB209 guidance and an analysis of crop-available phosphorus, potassium, magnesium, and soil pH.
Up-to-date SOM analysis is vital to meet the requirements of the Sustainable Farming Incentive (SFI)’s SAM1 action for soils. Not all standard soil testing includes SOM analysis, so growers may not qualify even if they have soil nutrient analysis results from the last 5 years.
“There are plenty of advantages to SOM analysis,” continues Sajjad. “Benchmarking SOM levels will enable growers to assess the effect of any management changes and help not only improve soil health but also help them learn how to withstand extreme or unexpected weather conditions. So, adding SOM to regular standard soil testing is vital if we are to improve sustainable productivity, meet sustainability targets and protect the natural environment agriculture relies on—something the whole industry should be striving toward.”
