Nitrogen cycling in Pinus sylvestris stands exposed to different nitrogen inputs
Abstract:The objective of this study was to quantify the effects of high nitrogen (N) inputs on N cycling in a 35-45-yr-old Scots pine ( Pinus sylvestris L.) forest. Nitrogen was added annually (single doses) as NH 4 NO 3 in doses of 0 (N0), 30 (N1) and 90 (N2) kg N ha −1 yr −1 . The only N input to the N0 plots was atmospheric deposition of 10 kg N ha −1 yr −1 . The N cycle in these plots was tight, with almost complete retention of the incoming N. In the N1 plots the N retention was 83% after 9 yrs of N addition. The trees were the major sink, but the soil also contributed to the N retention. In the N2 plots the N retention was 63%, being mainly accounted for by accumulation in the soil. The leaching of N from the N2 stands was as high as 35 kg N ha −1 yr −1 . The N2 system was N saturated.
Document Type: Research Article
Affiliations: Department of Plant and Environmental Sciences Agricultural University of Norway NO-1432 P.O. Box 5028 Ås Norway
Publication date: February 1, 2004