Maximizing soil organic carbon stocks through optimal ploughing and renewal strategies in (Ley) grassland

Abstract

Grassland management effects on soil organic carbon storage under future climate are unknown. Here we examine the impact of ley grassland durations in crop rotations on soil organic carbon in temperate climate from 2005 to 2100, considering two IPCC scenarios, RCP4.5 and RCP8.5, with and without atmospheric CO₂ enhancements. We used the DailyDayCent model and a long-term experiment to show that ley grasslands increase soil organic carbon storage by approximately 10 Mg ha⁻¹ over 96 years compared with continuous cropping. Surprisingly, extending ley duration from 3 to 6 years does not enhance soil organic carbon. Furthermore, in comparison with non-renewed grasslands, those renewed every three years demonstrated a notable increase in soil organic carbon storage, by 0.3 Mg ha⁻¹ yr⁻¹. We concluded that management of ploughing and renewal intervals is crucial for maximizing soil organic carbon stocks, through balancing biomass carbon inputs during regrowth and carbon losses through soil respiration.

Soil carbon preservation can be enhanced under future climate change by including short duration ley grasslands into crop rotations and adjusting ploughing and ley sowing frequency over continuous grassland, according to process-based modelling and long-term field experiments in western France.