Model-based assessment of organic fertilization as alternative to mineral P under future climate change

Summary

Using the AgroC model informed by decades of field data from Bad Lauchstädt, Germany, this study compared five fertilisation strategies across 81 years of simulated climate scenarios to assess whether optimised organic manure applications could replace mineral phosphorus. Whilst low manure inputs (FYM_20) led to phosphorus depletion and yield losses, optimised manure regimes (FYM_37 and FYM_37+N) maintained yields comparable to or exceeding mineral fertilisation for barley, potato and sugar beet, with modest nitrogen supplementation required only for winter wheat. Climate warming (RCP8.5) increased phosphorus depletion by 10–15% relative to moderate scenarios, but fertilisation management emerged as the dominant driver of outcomes.

Regional applicability

Findings are applicable to UK arable and mixed farming systems given similar soil types and crop rotations in temperate maritime climates, though UK farmers may face different manure availability and seasonal moisture dynamics. The work supports policy moves towards reduced reliance on finite mineral phosphorus reserves, although UK-specific validation at contrasting soil and climatic sites would strengthen recommendations.

Key measures

Crop yields (winter wheat, spring barley, potato, sugar beet), soil phosphorus dynamics, phosphorus leaching, nitrogen requirements

Outcomes reported

The study simulated crop yields and soil phosphorus dynamics across five fertilisation strategies under two climate scenarios (RCP4.5 and RCP8.5) from 2019 to 2100. It assessed whether optimised organic fertilisation could replace mineral phosphorus inputs whilst maintaining yields and soil phosphorus status in a four-crop rotation.

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