O. J. Lukkala. (1920). Lisä ortsteinikysymyksen valaisemiseksi. Acta Forestalia Fennica vol. 16 no. 5 article id 7047. https://doi.org/10.14214/aff.7047

English title: Studies on the effect of ortstein on paludification.

Original keywords: soistuminen; podsoli; ortstein

English keywords: paludification; podzol; ortstein

Abstract | View details | Full text in PDF | Author Info

No agreement has yet been reached about formation of podzols, and their distribution in Finland has not been studied. It is, however, known that most of the forest soils are leached. The compacted ortstein is relatively rare in Southern Finland, but common in the gravely soils in Lapland. This study focuses on whether ortstein formations facilitate paludification. The study is based on observations in drained peatlands in Toivakka and Multia. Ortstein can rarely be found under the actual peatlands. It is often formed in mineral soil threshold areas, where it can be up to one meter thick. The ortstein formation was stronger in poorer soil types. Also, it is compacted into a harder layer in gravely soils than in sandy soil. These formations seem to be caused by humus-rich water flowing from the peatlands.

The soil is not leached, and ortstein is not formed in wet, low-lying peatlands, and has, therefore, no role in their paludification. In drier peatlands, especially in slopes, an A horizon can be found. However, ortstein seems not to have a marked effect on paludification. When ortstein is formed in mineral soil threshold areas, their formation seems to be caused by water flow from the peatland. It may make the threshold area more compact, and thus further facilitate paludification.

The PDF includes a summary in German.

Lukkala, E-mail: ol@mm.unknown

Category : Research article

article id 625, category Research article

Hans-Örjan Nohrstedt. (2000). Effects of soil scarification and previous N fertilisation on pools of inorganic N in soil after clear-felling of a Pinus sylvestris (L.) stand. Silva Fennica vol. 34 no. 3 article id 625. https://doi.org/10.14214/sf.625

Keywords: boreal forest; mound; Sweden; furrow; nitrogen mineralisation; podsol

Abstract | View details | Full text in PDF | Author Info

Previous analyses of soil water beneath mounds resulting from scarification have implied that this forestry measure increases leaching of inorganic N. However, more recent soil-water studies have not confirmed this assumption. The soil study presented here examined the pools of inorganic N in different microsites emanating from a simulated disc trenching, i. e. the mound with underlying soil, the furrow bottom and the undisturbed soil. The study was made five years after scarification. The mound itself with underlying soil had a larger pool of inorganic N than the undisturbed soil. This was mainly because of an increase in the embedded humus layer, thus implying a larger net N mineralisation and/or lower losses. However, when pools of inorganic N per hectare were calculated, taking into consideration that a scarified area comprises 25% mounds, 25% furrows and 50% undisturbed soil, there was no increase in pools of inorganic N when compared with an area not subjected to scarification. This observation supports the finding of the more recent soil-water studies mentioned, i. e., that leaching seems not to be influenced by soil scarification. The scarification was made as a split-plot treatment on main-plots in an old experiment with different N doses. Thus, the effect of the previous N fertilisation could also be evaluated. Two N doses were tested beside the unfertilised control: 720N (3 x 240 kg N ha–1 yr–1) and 1800N (3 x 600 kg N ha–1 yr–1). The last fertiliser application was made six years before the clearcutting and 13 years before the soil sampling. The previously fertilised main-plots had larger pools of inorganic N than the control plots.

Nohrstedt, The Forestry Research Institute of Sweden, Uppsala Science Park, SE-751 83 Uppsala, Sweden E-mail: hans-orjan.nohrstedt@skogforsk.se

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