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Impact of the North Atlantic Oscillation on Swedish Winter Climate and Nutrient Leaching
Author(s) -
Ulén Barbro,
Lewan Elisabet,
Kyllmar Katarina,
Blomberg Maria,
Andersson Stefan
Publication year - 2019
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2018.06.0237
Subject(s) - environmental science , leaching (pedology) , north atlantic oscillation , snowmelt , nutrient , hydrology (agriculture) , arable land , snow , agriculture , soil water , geography , ecology , biology , climatology , geology , soil science , geotechnical engineering , meteorology
The winter climate in northwestern Europe is commonly influenced by the North Atlantic Oscillation (NAO). Its intensity, expressed as an index (NAO i ), has been suggested for use in assessing nutrient leaching from arable land to water and the effects of mitigation measures. We found significant ( p < 0.05) positive linear relationships between NAO i and an air freezing–thawing index in central and southern Sweden for 2004 to 2016. This period covered winters with both extreme low and high NAO i . There were significant negative linear relationships between NAO i and a snow depth index. Management and nutrient leaching were studied simultaneously in two agricultural catchments (20.7 ha, code 11M; 788 ha, code M36) in southwestern Sweden. Catchments 11M (silty–clay soil) and M36 (sandy hills with a central, heavy clay plain) are both artificially drained. Total N and total P leaching increased significantly with winter (November–April) NAO i in both catchments. In contrast, leaching of dissolved reactive P (DRP) was not related to NAO i . The highest DRP concentrations were observed in connection with specific agricultural practices, whereas moderately elevated DRP concentrations were linked to snowmelt events. Concentrations of P in other forms (other P) were even more elevated (1.02 mg L −1 ) in 11M in winter 2014–2015, probably due to a large (32% of area) internal buffer (ley–fallow) in a central ravine being plowed down in autumn 2014. No general trend in P or N fertilization was found in catchment M36. Thus NAO i may be appropriate for use in trend analyses of nutrient load in the study region. Core Ideas North Atlantic Oscillation (NAO) intensity index (NAO i ) influences annual winter climate. NAO i has an impact on regional nutrient leaching. Moderate particle P leaching may reflect low NAO i and high snow depth index. NAO i influences erosion less than ploughing down strategic unfertilized buffer zones.