Markku Yli-Halla

Pitääkö kaikkein happamimmat sulfaattimaat poistaa viljelystä?

Yli-Halla M. Pitääkö kaikkein happamimmat sulfaattimaat poistaa viljelystä?

Tiivistelmä

Estimates of the area of cultivated acid sulphate soils in Finland range from 50,000 ha to 336,000 ha. In these soils, sulfides are oxidized to sulphuric acid upon aeration, which is promoted by drainage. Agricultural use of these soils requires abundant liming. Acidic drainage waters impact the aquatic life negatively. Early research concentrated on the agricultural utilization of acid sulphate soils while more recently environmental aspects have been emphasized. Controlled drainage, aiming at a high water table, is considered an option for the management of acidity. Owing to evapotranspiration, however, sulfidic layers may be exposed to oxidation every summer in spite of controlled drainage. Successful submerging of sulfidic layers may require pumping of water to the field from outside sources. Abandoning the most acidic sulphate soils and stop draining them would prevent further oxidation of sulfides. This is a sensitive issue, because the farmland is private property. Moreover, it is not exactly known where the most acidic sulphate soils are located and how their abandonment would impact the quality of water in recipient rivers.

Avainsanat
agriculture; Drainage; acidity; sulphur; sulphate soils

Vastaanotettu 31.10.2017 Julkaistu 1.1.2003

Katselukerrat 2544

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