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Application of oil-shale ash and straw mulch promotes the revegetation of extracted peatlands

Triisberg-Uljas, Triin, Vellak, Kai, Karofeld, Edgar
Ecological engineering 2018 v.110 pp. 99-106
field experimentation, land restoration, mulching, oil shale, peat, peatlands, plant growth, straw mulches, Estonia
The spontaneous revegetation on abandoned peat extraction areas is a slow and sporadic process. We conducted an open field experiment to clarify how to promote the revegetation of abandoned extracted peatlands. Two extracted peatlands in East Estonia with three treatments and control were analysed two, three and five years later. Our aim was to elucidate if fertilising with alkaline oil-shale ash promotes revegetation of bare peat fields; whether it speeds up establishment of plant species characteristic of natural mires; and whether the closeness to vegetated areas near the peatland edge has an effect on the formation of plant species composition.Our results showed that application of oil-shale ash and straw mulch, as well mulch alone promote clearly revegetation in studied extracted peatlands (mean plant cover 57% and 40% on fifth year, correspondingly), but at the same time quadrats with oil-shale ash alone were sparsely vegetated (4%) and similar to plots without any treatment (2%). Oil-shale ash alone did not speed up the establishment of plant species, but oil-shale ash combined with straw mulch facilitated the establishment of some species typical of natural mires. Closeness to the peatland edge increased the number of species and their cover because of the location and proximity to naturally vegetated areas. Consequently, oil-shale ash combined with straw mulch or straw mulch alone facilitated plant growth on extracted peatlands, while the effect of oil-shale ash alone was unimportant.