Field trials have confirmed the environmental risks linked to the conversion of permanent or improved grassland to arable farming.
The studies, carried out by scientists at Rothamsted Research, found that converting grassland to arable cropping caused immediate and substantial declines in soil quality.
Soil organic matter dropped by 45%, while soil carbon and nitrogen both fell by 41%, and phosphorus declined by 61%.
These changes indicate rapid depletion of key macro-nutrients essential for long-term soil fertility.
At the same time, pollution emissions to water increased.
After conversion, concentrations of nitrogen species and carbon in runoff increased significantly, with nitrogen species losses rising by 200-300 times.
The research also examined carbon dioxide exchange between the farmed land and the atmosphere.
While all systems showed seasonal variations, permanent pasture consistently acted as a stronger carbon sink than other systems.
The differences among the three systems were not statistically significant.
In comparison with the arable conversion treatment, grass-based systems maintained more stable soil conditions and nutrient levels.
Permanent pasture, in particular, retained higher levels of soil carbon, nitrogen, and phosphorus, and showed more consistent emissions to water.
Dr. Laura Cardenas from Rothamsted commented: “The multiyear datasets are an incredibly valuable resource to really understand agricultural systems and their potential for increasing food productivity without further environmental damage.
“Additionally, they help us to separate the influence of climate and farming activities on the natural ecosystem.”
Prof. Adie Collins, science director at Rothamsted Research added: “These findings highlight the need to carefully balance food production with the protection of our natural resources, and the environmental risks associated with converting grassland to arable production to feed a growing global population.”
Land use planning tool
Meanwhile, agricultural consultancy ADAS has launched a new land use planning tool to support farmers and managers with making sustainable yet profitable land use decisions.
The tool, christened LUMEO, uses satellite imagery and machine learning to offer land managers suggestions on how to maximise environmental gains and financial returns from their land.
After inputting farm data and the desired end-goal – such as carbon sequestration, biodiversity net gain credits, diversification or energy generation – users are presented with a shortlist of economically viable actions to reach that goal while turning a profit.
ADAS environmental modeller Dan Hobley, developer of the tool, explained: “Where LUMEO differs from other tools on the market is its ability to generate ideas.
“It doesn’t require you to already know the actions you want to try out.
“”It will suggest actions based on what is possible on your holding and take into account any ongoing farm business requirements.”
For those who already have a plan in place, LUMEO can suggest suitable locations for change using a satellite map of the holding, prioritising unused or underutilised land for maximise productivity.