%0 Research article
%T Retention of phosphorus in peatland buffer zones at six forested catchments in southern Finland
%A Väänänen, Riitta
%A Nieminen, Mika
%A Vuollekoski, Martti
%A Nousiainen, Hannu
%A Sallantaus, Tapani
%A Tuittila, Eeva-Stiina
%A Ilvesniemi, Hannu
%D 2008
%J Silva Fennica
%V 42
%N 2
%R doi:10.14214/sf.253
%U https://silvafennica.fi/article/253
%X Our current knowledge of the P retention efficiency of peatland buffer  zone areas used to reduce sediment and nutrient leaching from forestry  areas is insufficient. Especially the role of P sorption by soil in  buffer zones needs closer examination as there is considerable variation  in the efficiency of P retention. Six sites in southern Finland were  chosen for the study. The buffer zone areas varied between 0.1–4.9% of  the catchment area. A total of 10 kg of solute PO<sub>4</sub>–P was added to the inflow of the buffer zone areas and the concentrations of PO<sub>4</sub>–P  in inflow and outflow were measured for 2–4 years. P retention  characteristics of the surface peat were determined with  sorption-desorption isotherms before and after PO<sub>4</sub>–P addition  and the effective buffer zone area over which the added P was spread  was determined from soil water samples. P retention in the two largest  buffer zone areas was complete (100% retention), and the third largest  buffer retained 94%. Retention in the three smallest buffer zones was  24%, 95% and 95% of the added P. As a result of P addition reduction in  peat P retention capacity was detected in three out of four cases. The  effective buffer zone area varied from 67% to 100% of the total buffer  zone area. Factors contributing to efficient P retention were large  buffer size and low hydrological load whereas high hydrological load  combined with the formation of preferential flow paths, especially  during early spring or late autumn was disadvantageous. High P retention  capacity in peat contributed to the sustainability of P retention. The  study showed that even relatively small buffer zone areas are able to  efficiently reduce P load.