Greenhouse gas emissions from managed peat grasslands in the Netherlands

Peat soils in the Netherlands are generally drained for grassland production and dairy farming. This results in an increased oxygen content of the soil, and consequently accelerated decomposition of the organic matter present, with associated emissions of the greenhouse gases carbon dioxide (CO₂) and nitrous oxide (N₂O). Decomposition can be mitigated by raising the groundwater level, but the effects on greenhouse gas emissions is not fully understood, particularly in combination with other agricultural practices. The aim of this PhD was to study the mechanisms behind these emissions in lab and field experiments. This thesis demonstrated that soil moisture as well as oxygen content are limiting factors for peat soil decomposition, and that reducing drainage may help to reduce CO₂ emissions from peat soils. The effect of a raised groundwater level on N₂O emissions is less clear however, as N₂O can also be stimulated by wetter soil conditions. This may particularly be the case in combination with grazing cattle and the application of mineral fertilisers.