Long-term tillage reduction helps to restore the soil’s natural phosphorus cycle, supporting more sustainable nutrient management with less reliance on costly and finite fertilizer inputs, a new study reveals.
It demonstrates the potential of lower tillage, not only as a soil protection practice but also a tool for sustainable nutrient management and food security under future climate change conditions.
The international study of long-term agricultural field sites across Europe, led by a team at CSIC-INIA, Madrid, found that long-term tillage reduction increases soil phosphatase activity, enhancing organic phosphorous mineralization. This supports reduced reliance on inorganic phosphorous fertilizers for more sustainable agriculture.
The study, ‘The distribution and kinetics of phosphatase activity in European agricultural soils under long-term tillage reduction practices’, appeared in Sustainable Microbiology, an Applied Microbiology International publication, and was driven by an international team of soil scientists and agroecologists from European research institutions and universities.
Inorganic fertilizers
The study addresses the growing difficulty of sustaining agricultural productivity while reducing dependence on inorganic phosphorus fertilizers, which are energetically costly, finite, concentrated only in a few regions of the world, and environmentally damaging, according to corresponding author Professor Juan Luis Ramos, of CSIC, Spain.
“The study was conceived to determine how-long term tillage reduction can improve soil biological functioning, particularly phosphatase activity, to enhance the natural mobilization of organic phosphorus, reduce nutrient losses and support a more sustainable soil management across European farming. In short, we aimed to promote the natural phosphorous cycle in agricultural soils,” he said.
The team coordinated a standardized sampling campaign in seven long-term agricultural experiments in Europe that have been managed under different tillage practices for more than a decade. This unique setup allowed them to assess how contrasting agricultural practices influence soil processes under real farming conditions. In this study they focused specifically on the soil phosphorous cycle.
Study highlights
The highlights of the study are:
- Long-term tillage reduction enhanced phosphatase activities in the topsoil
- Under no-tillage, the catalytic efficiency (Vmax/Km) of phosphatases increased
- Total nitrogen showed a pivotal role as a phosphatase driver
- Increased soil moisture by reducing tillage could sustain P cycling in dry areas
Unexpected findings
“What was not entirely surprising is that long-term tillage reduction increased phosphatase activity in the top-soil - that aligns with existing knowledge that reduced disturbance enhances microbial activity and organic matter accumulation,” Professor Ramos said.
“What was surprising and new was the consistent increase in phosphatase catalytic efficiency (Vmax/Km) under no-tillage, suggesting more efficient P acquisition strategies; the central role of total nitrogen as a dominant driver of both acid and alkaline phosphatase across very different European soils, indicating a strong Nitrogen/Phosphorous coupling that is often underappreciated; and the indication that improving soil moisture under reduced tillage can help sustain the P cycle in dry regions, given these results’ relevance under climate change scenarios.”
Management practices
The results of the project show that management practices can actively favor the soil’s natural phosphorous cycle, rather than relying on external fertilizer inputs. The fact that long-term tillage reduction enhances phosphatase levels and efficiency and that this is linked to soil moisture and soil nitrogen, support that farmers can unlock existing organic phosphorus reserves in soils.
“This matters in the real world because inorganic fertilizers are finite, unevenly distributed globally, energy-intensive to produce and a major source of water pollution.
“So reduced tillage can help maintain crop productivity while lowering fertilizer needs. Furthermore, long-term reduced tillage is not only a soil protection practice but also a tool for sustainable nutrient management and food security particularly under coming climate change conditions.”
Next steps
The next step will be to move from these demonstration assays to practical scalable reductions in phosphorous fertilizer use based on biological functioning, said Professor Ramos.
“This will make it feasible to refine fertilizer recommendations for different tillage practices, support and incentive conservation tillage, and develop tools to help farmers to reduce P inputs without affecting crop yields.”
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The general coordinator of the study is Marta Goberna, from CSIC-INIA, Madrid (Spain). Research in all the laboratories was financially supported by the European Union H2020 Research and Innovation Programme under grant agreement No. 862695 (European Joint Programme SOIL, TRACE-Soils project).
Research in Juan Luis Ramos´ laboratory was also funded by Plan Nacional PID2021-123469OB-IOO funded by MICIU/AEI/10.13039/501100011033 and by “ERDF A way of making Europe”, by “ERDF/EU.”
‘The distribution and kinetics of phosphatase activity in European agricultural soils under long-term tillage reduction practices’ is published in Sustainable Microbiology.
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