Chronic Nitrogen Amendment Plots Fine Root Biomass and Percent N Data Pre-treatment (1988) and year 4 (1991) data "." indicates missing data f/n: hfroots.asc NOTES ON CALCULATIONS: All samples averaged for 1988 and separated by control, low N and high N plots in 1991 (roots not collected from N+S plots). Mineral soil sampled to 10 cm. Biomass differences between 1988 and 1991 are not directly comparable due to: 1) inclusion of live and dead roots in 1988; 2) inclusion of only select species in 1991 and 3) size class 0-2 mm in 1988, 0-1 mm in 1991. Estimated total N content is mass times % nitrogen for 1988. For 1991 control values it is 1988 mass times 1991 % nitrogen. For 1991 treatments, it is 1988 mass times (treatment mass/control mass) times % nitrogen. Estimated Biomass N Content Year Plot Soil Horizon Root %N (kg/ha) (kgN/ha) 1988 PINE Organic 1.6 1445 23.6 1988 PINE Mineral 1.2 1594 18.3 1988 HARD Organic 1.2 3324 39.6 1988 HARD Mineral 0.9 2609 22.4 1991 PC Organic 1.7 332 23.8 1991 PC Mineral 1.2 526 19.8 1991 PL Organic 2.1 528 47.8 1991 PL Mineral 1.7 830 43.5 1991 PNS Organic . . . 1991 PNS Mineral . . . 1991 PH Organic 2.5 308 33.5 1991 PH Mineral 2.2 744 49.4 1991 HC Organic 1.3 427 43.2 1991 HC Mineral 1.1 289 27.9 1991 HL Organic 1.4 765 84.6 1991 HL Mineral 1.1 387 36.7 1991 HNS Organic . . . 1991 HNS Mineral . . . 1991 HH Organic 1.4 713 79.4 1991 HH Mineral 1.3 509 58.8