Altered litter quality drives changes in litter decomposition following implementation of a regenerative measure in Dutch peat meadows

Abstract

The majority of NW European peatlands are degraded due to conventional grassland-based livestock farming (i.e. lowered groundwater levels, high nutrient inputs and high mowing frequencies) leading to increased CO₂ emissions and soil nutrient levels, and reduced biodiversity. Creating regenerative ditch borders along drainage ditches that surround agricultural fields could ameliorate some of these negative effects. We investigated the effects of ditch border type (conventional vs. regenerative) on litter decomposition (standardized litter using Tea Bag Index, and locally collected leaf and root litter), vegetation composition, litter quality, and soil characteristics along transects that extended from the water's edge into the adjoining field (40 cm, 80 cm, 360 cm and 640 cm) in a peat polder in North Holland, the Netherlands. The decomposition rate of standardized litter was unaffected by ditch border type, however the stabilization factor was 43% and 35% lower in regenerative ditch borders at 40 cm and 80 cm from the water's edge, respectively. Leaf litter collected from regenerative borders decomposed 75% slower than leaf litter from conventional borders. Regenerative soils were higher in organic matter content, carbon and nitrogen content, and soil moisture content, and lower in bulk density and soil compaction. This pattern was related with a lower decomposition rate and stabilization of standardized litter. Changes in litter decomposition are predominantly driven by a lower leaf litter quality produced at regenerative borders. Efforts to reduce carbon emissions should therefore focus on reducing decomposition rates by creating conditions that stimulate plant species producing litter of a lower quality.