This study examined changes in stream and soil water NO3−and their relationship to temporal and spatial patterns of NO3−in soil solution of watersheds at the Fernow Experimental Forest, West Virginia. Following tenfold increases in stream NO3−concentrations over a 13-year period (1969–1981) on untreated WS4, concentrations have declined through 2006. Followingfourfold increases in stream NO3−on treatment WS3 from pretreatment levels to a 1998 maximum, concentrations have declinedthrough 2006, despite additions of N. Concentrations of soil water NO3−were consistently lower for WS4 compared to WS3.Data for soil water NO3−on WS3 versus WS4 followed patterns of net mineralization and nitriﬁcation for these watersheds.Nitrogen additions to WS3 decreased spatial heterogeneity of N processing, which was largest in the pretreatment year anddecreased signiﬁcantly to a minimum by 2000-2001. Concurrently, soil water NO3−increased on WS3 from 1.3 mg NO3−-N L−1inpretreatment 1989 to a maximum of 6.4 mg NO3−-N L−1in 2001. Spatial heterogeneity in soil water NO3−on WS4 remained highduring this period. Data suggest that temporal patterns of stream NO3−may be inﬂuenced by spatial heterogeneity of watershedprocesses which vary over time in response to N availability.
Gilliam FS and MB Adams. 2011. Effects of nitrogen on temporal and spatial patterns of nitrate in streams and soil solution of a central hardwood forest. ISRN Ecology, Article ID 138487, doi:10.5402/2011/138487.