In July 2011, soil samples were collected from control, and N+P plots from within a set of treatments in Moist Acidic Tundra plots established in 1989. A set of of Control and N+P plots established on an adjacent hillslope in 2006 with both equivalent (high) and half (low) the fertilization rate of the 1989 plots were also sampled. At the time of sample collection we separated the soil into organic horizon, organic/mineral interface, and the upper 5cm of the mineral soil, and measured the depth of each layer. We determined percent moisture for all soils and quantified the biomass of members of the belowground community. Total carbon and nitrogen of all soils were quantified by dry combustion using a Leco TruSpec CN analyzer (Leco Corporation, St. Joseph, Michigan). Direct count slides for microbial biomass estimation were made using the methods of Bloem (1995) as adapted by Frey et al. (1999). 10ml of a soil solution diluted 1:100 (5g initial soil mass) was added to each of 5 6mm diameter wells on a slide. Bacteria slides were stained with DTAF (5-(4, 6 dichlorotriazin-2-yl) aminofluorescein) and Fungi slides were stained with calcifluor M2R fluorescence brightener. Direct counts were made using epifluoresence microscopy. Bacteria were counted, 10 images per well, 2 wells per sample. Fungal hyphal length (Lodge and Ingham 1991) was estimated using the formula of Newman (1966): R=πNA/2H where N=number of hyphae crossing transect line, A=area of well, H=total length of transects. 2 wells, each with 10 images, 3 transects per image were used.
Protozoa densities were estimated from 10 g soil samples using Most Probable Number MPN (Darbyshire et al. 1974; Ingham 1994). 10 g soil was serially diluted 10-1-10-6. Using a 24-well tissue culture plate, four replicate wells of each of the six dilutions were created by adding 0.5 ml soil solution to the wells (Rusterholz and Mallory 1994). E. coli, a bacterium food source for protozoa was added to each of the wells. Protozoa were separated into the broad categories of Amoebae, Flagellates and Ciliates. Nematodes were isolated from 20 g of soil samples using Baermann Funnels (Hall 1996). Nematodes were preserved in formalin, counted and identified to functional group based on the morphology of the stoma and stylet (Niles 1994). Rotifers, Tardigrades, and Enchytraeids were isolated from 5 g of soil using the methods of Peters et al. (1993). Microarthropods were heat-extracted into 70% ethanol from soils using Tullgren funnels (Moore et al. 2000). The intact sample pairs from each plot were wrapped together in cotton cheesecloth, weighed, placed over a funnel, and heated with a 9-W incandescent lightbulb for 5 days until dry.

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