Plots were setup as indicated below, with annual fertilization treatments of 10 g/m2 Nitrogen (as NH4NO3) and 5 g/m2 Phosphorous (as triple superphosphate) . Greenhouses and shade houses were annually set up in late May or early June and removed in the end of August or early September.
Sites:
Toolik Inlet “Block 1” (CT, N, P, NP, GH, GHNP, and Shade treatments)
Treatments began summer of 1989; one 5x10m plot/treatment
Toolik Outlet "Block 2" (Same treatments)
Treatments began summer of 1989; one 5x10m plot/treatment
Toolik Outlet "Block 3" (Only CT, N, P and NP)
Treatments began summer of 1989; one 5x10m plot/treatment
Sag River toposequence "Block 4" (CT, N, P, and NP treatments)
Treatments began fall 1985 , 2 replicate plots,
each 2x10 m

Calculations: Units; Tissue mass data are expressed in g/quadrat (400 cm2). Multiply by 25 to get g/m2.

Reference Citations: Shaver, G. R. and F. S. Chapin, III. 1991. Production/biomass relationships and element cycling in contrasting arctic vegetation types. Ecological Monographs 61:1-31.

Sampling Description.

Biomass quadrats, size 20x20 cm, were randomly located along line transects within plots. For Toolik control and NandP there were d and for GH and GHNP 4 quadrats/plot collected. At the Sag site 4 quadrats//treatment were collected. All aboveground biomass plus belowground stems and rhizomes were clipped in 20x20 cm quadrats. Aboveground biomass is considered "within" the quadrat if it is associated with a meristem that is within the quadrat. Quadrats were sorted within 24 hours into species and then into tissue type. Tissue categories were standard, except for graminoid sheaths. Because some species, especially Carex cordirhiza, included many culms, "sheaths" included culms as well. Leaf Blades were the only other aboveground biomass category for graminoids, so inflorescence also went into the "sheaths" category. This is potentially a problem in analysis, because much of the mass of C. cordirhiza is culms and attached, aboveground sheaths, whereas the "sheath" category for other graminoids is almost entirely belowground and non-green. After several days in the oven samples were weighed to nearest milligram. Samples are then returned to Woods Hole for nutrient analysis. Details are given in Shaver and Chapin (Ecological Monographs, 61(1), 1991, pg. 1.)