Soil ammonium accumulation after sod cutting hampers the restoration of degraded wet heathlands

Abstract

Summary 1.Restoration of formerly species-rich wet heaths and matgrass swards has not always been successful. The constraints on this restoration process are not yet fully understood and need further investigation, particularly the accumulation of ammonium in the soil after sod cutting, i.e. the removal of the vegetation and topsoil layer. This accumulation is known from sod cutting experiments in dry heaths, but had not previously been studied in wet heaths and matgrass ecosystems. 2. In 2000, sods were cut from two degraded Dutch wet heaths. Soil chemistry and germination in the sod-cut plots were measured at irregular intervals between April 2000 and August 2001. To test the influence of ammonium on germination and survival, a glasshouse dose-response experiment was conducted with two endangered wet heath plant species. 3. In both wet heaths, an accumulation of KCl-extractable ammonium up to 600 µ mol kg − 1 dry soil was found in the upper 10 cm of the soil within the first year after sod cutting. These high ammonium concentrations lasted for about 10 months. Germination was very low in the sod-cut plots in 2000 and 2001, and few target species were found, although they were present in the vicinity. 4. The dose-response experiment indicated a significant, negative correlation of both germination and survival with increasing ammonium addition for both plant species. Mean soil ammonium concentrations of the control, 100 and 250 µ  ammonium treatments were significantly lower than those of the 500 and 1000 µ  ammonium treatments (47, 45, 70, 144 and 252 µ mol kg − 1 dry soil, respectively). 5. Maximum concentrations of KCl-extractable ammonium in the field corresponded to water-extractable concentrations that were higher than those found to be limiting germination and growth in the glasshouse experiments. The low germination in the field is likely to have been adversely affected by high concentrations of ammonium as a result of sod cutting. 6. Synthesis and applications . High ammonium concentrations occur in wet heaths following sod cutting. Low rates of germination of restoration target plant species occur under such conditions. To increase the success of wet heath restoration, the accumulation of ammonium after sod cutting should be prevented by additional measures, such as liming. Because sod cutting is also applied as a restoration measure in the restoration of other ecosystems, such as fens, the effects on increased soil ammonium concentrations need further attention.

Legacy effects of altered flooding regimes on decomposition in a boreal floodplain

“…It is well known that soil disturbance can cause local and temporal changes in soil properties such as aeration, pH, nutrient availability and in microbial community composition and activity (Allison and Martiny 2008;Dorland et al 2003;Wagner et al 2015;Wardle et al 2004), which all are known to affect litter decomposition (e.g., Hattenschwiler et al 2005;Veen et al 2015). In addition to previous studies however, our results now show that such disturbance effects can be modulated by litter type and flooding history.…”

Can management compensate for atmospheric nutrient deposition in heathland ecosystems?

“…Quantities of leached N under the sod-cut subplots were particularly high. This may be attributed to several factors, such as the absence of N uptake by plants and increased mineralization rates of roots and organic material in the remaining A-horizon (Mitchell et al 1999;Dorland et al 2003). Elevated mineralization rates are induced by increased soil temperatures and soil moisture levels, both affected by the removal of vegetation (Mallik & FitzPatrick 1996).…”

“…2004;Niemeyer et al . 2005) and one as a high-intensity measure (sodcutting; Dorland et al . 2003;Terry et al .…”

Demographic vulnerability of the clonal and endangered meadow thistle

“…Creating gaps in the vegetation also enables the otherwise strongly limited establishment of seedlings in the grasslands. Earlier reported negative effects of initial ammonium peaks after sod-cutting (Dorland et al 2003) do not seem to limit seedling establishment in the long run, provided that seed sources are nearby. A positive aspect of nutrient-enrichment in these grasslands is that the elevated seed production may result in higher colonization rates of sod-cut areas, provided again that those new habitats are not too far away from the seed source.…”