Authors: Anu Vikman Sakari Sarkkola Harri Koivusalo Tapani Sallantaus Jukka Laine Niko Silvan Hannu Nousiainen Mika Nieminen
Publish Date: 2010/01/19
Volume: 641, Issue: 1, Pages: 171-183
Abstract
We studied the nitrogen retention capacity of six peatland buffer areas constructed in forested catchments in southern and central Finland The buffers 01–49 of the total catchment area were either undrained mires or drained peatlands rewetted 4–7 years before the present study The N retention capacity was studied by adding ammonium nitrate NH4NO3–N solution into the inflow waters of the buffers once one area or twice five areas during a period of 4–6 years Except for the first N addition in one area the three largest buffer areas relative size 1 retained the added inorganic N almost completely their retention efficiencies during the year of addition were 93 for both NO3–N and NH4–N Two of the three small buffers relative size 025 were also able to reduce inorganic N from the throughflow waters effectively their retention capacities for inorganic nitrogen varied between 58 and 89 However one small buffer area had a retention capacity of only 20 The factors contributing to efficient N retention were hydrological load during N addition relative size of the buffer area and its length ie the distance between the inflow and outflow points If there was any release of the added N it mostly occurred within a relatively shorttime period 100 days after the treatment The buffer areas appeared to be efficient and longterm sinks for inorganic nitrogen because the release of N during the 2–4 years after N addition was minor
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