Table 1: Species used in the experiment. FF represents the functional form types derived by Levang-Brilz and Biondini [14] based on the morphological and physiological characteristics listed in this table. β and 𝜌 are scaling constants that relate root biomass (RB (g)) to root lateral spread (RLS (m) = 𝛼 R B 𝛽 ) and root surface area (RSA (m2) = 𝜂 R B 𝜌 ), while τ is a scaling constant for root plasticity ( 𝜏 = 0 no plasticity) derived by Biondini [15] using data from Johnson and Biondini [16]. R : S is the root-to-shoot ratio; RGR is relative growth rate (g g−1 d−1); NUE and PUE are N and P use efficiency (g·gN−1 and g·gP−1, resp.); Imax-N and Imax-P are the maximum N or P uptake rate per unit of root surface area (g·m−2·d−1). Nomenclature follows the PLANTS Database (http://plants.usda.gov/), National Plant Data Center, Baton Rouge, La, USA.

SpeciesC3/C4FFβρR : SRGRNUEPUEImax-NImax-Pτ

Grasses
Agropyron cristatumC3G10.0070.5890.810.1144.41181.030.35760.10820.28
Andropogon gerardiiC4G10.5150.7461.570.1071.46251.040.19610.06690.08
Bouteloua curtipendulaC4G20.6310.3260.550.1360.02244.340.16280.05220.02
Bouteloua gracilis C4G20.5840.3680.760.0950.75153.600.39270.06710.00
Bromus inermisC3G10.4961.0660.710.1171.96173.480.36950.08550.08
Calamovilfa longifoliaC4G30.3720.2890.680.1154.66262.830.32890.07560.25
Elymus canadensisC3G30.4390.4731.090.1355.18190.451.34800.32210.34
Hesperostipa comataC3G20.6680.4790.740.0643.22190.160.24130.06460.26
Hordeum jubatumC3G10.6670.7190.870.1554.58129.280.24330.06410.27
Koeleria macranthaC3G20.4760.5560.490.1055.69152.260.06350.02020.29
Nassella viridulaC3G20.6020.3580.660.1053.55225.761.08240.21980.00
Panicum virgatumC4G10.2020.8840.610.1050.79131.910.13590.04850.24
Pseudoroegneria spicataC3G30.5270.5931.010.1145.85168.500.76740.22220.13
Poa pratensisC3G20.5440.2960.700.1352.43149.070.15010.05210.39
Schizachyrium scopariumC4G10.5340.6970.980.1162.69250.780.20430.06110.31
Sorghastrum nutansC4G10.3480.5140.980.0971.76201.860.49860.14390.00
Sporobolus cryptandrusC4G30.4430.4341.050.1448.14185.951.33370.37610.36

Forbs
Achillea millefoliumC3F10.4110.9681.670.1439.4298.140.43630.15170.92
Allium stellatumC3F20.5320.5691.850.0652.20141.270.11900.02810.10
Artemisia dracunculusC3F10.5880.7030.390.1343.20146.880.85070.25290.15
Artemisia frigidaC3F30.3760.7940.440.0950.88142.780.81660.07390.45
Asclepias verticillataC3F10.3380.5951.070.0966.14123.010.41050.12410.39
Aster ericoidesC3F30.4880.6230.960.1233.08142.821.31500.42920.50
Astragalus CanadensisC3F30.7260.4011.970.1344.36144.552.97240.70980.57
Chrysopsis villosaC3F10.4780.4610.750.0938.60127.010.18580.03450.76
Cirsium arvenseC3F10.5840.7180.980.1163.31114.990.24660.10830.03
Coreopsis lanceolataC3F10.3170.6180.670.1152.34163.830.34500.07370.35
Dalea purpureaC3F30.9320.8530.900.0938.93121.611.93110.55380.73
Gaillardia aristataC3F10.1700.9690.950.0832.4496.280.22670.07500.85
Galium borealeC3F20.3680.5671.420.0887.28249.760.08170.01850.25
Geum triflorumC3F10.4100.7030.670.0853.80127.380.32130.08500.33
Grindelia squarrosaC3F30.4490.5800.890.1439.2695.990.73720.21840.82
Helianthus maximilianiC3F30.5900.3250.920.1344.6697.030.71700.36070.81
Helianthus rigidusC3F10.2110.5960.810.0931.3165.970.36290.09120.30
Linum perenneC3F30.1130.6182.520.0946.58158.570.19310.04560.27
Lupinus perennisC3F11.2601.0001.190.1050.3698.670.63030.22511.15
Melilotus officinalisC3F10.5591.0762.780.1442.9482.541.28510.15790.38
Oenothera biennisC3F30.3550.2581.110.1981.0087.141.35040.64830.56
Potentilla argutaC3F10.3581.0010.460.1047.20153.390.39260.10580.25
Ratibida columniferaC3F10.4110.8020.410.1041.7587.560.99310.35860.50
Rosa arkansanaC3F30.4550.4560.640.1859.83346.722.00710.30751.08
Rudbeckia hirtaC3F10.6470.7030.640.1249.59113.301.08920.29790.80
Solidago missouriensisC3F10.5260.1210.690.1038.33264.750.02970.00250.72
Solidago rigidaC3F10.2450.7901.210.1059.12137.050.34770.08820.42
Taraxacum officinaleC3F10.3481.0730.720.1253.88136.760.55040.08750.61
Tragopogon dubiusC3F10.5780.9200.770.1041.33110.820.65710.22600.00
Verbena strictaC3F10.2830.7660.590.1136.70110.460.57210.16931.59
Vicia americanaC3F10.3560.5451.010.0838.17102.650.47900.17970.79