View Full Table | Close Full ViewTable 1.

Sources of data contributing to the univariate analyses and to the model.

 
Lowland ecotypes Upland ecotypes
Reference No. of observations No. of locations† No. of cultivars‡ No. of observations No. of locations No. of cultivars‡
Berdahl et al., 2005 72 2 8
Bouton, 2002 20 2 2 40 2 4
Casler and Boe, 2003 48 2 6
Casler et al., 2004 10 5 6 (2) 10 5 14 (2)
Cassida et al., 2005a 18 3 6 6 2 3
Fike et al., 2006 96 7 2 96 7 2
Fuentes and Taliaferro, 2002 56 2 3 70 2 6
Kiniry et al., 1996 17 5 1
Kiniry et al., 1999 19 1 1
Lemus et al., 2002 12 1 4 48 1 16
Muir et al., 2001 45 2 1
Sanderson et al., 1996 15 2 1
Sanderson et al., 1999a 71 2 1
Sanderson et al., 1999b 166 5 6 67 5 6
Sanderson et al., 2004 10 1 1
Schmer et al., 2008 29 10 4
Sladden et al., 1991 6 1 3 10 1 5
Thomason et al., 2004 133 2 1
Location refers to the geographic designation used by the author for a site (or group of co-located sites), and to a unique latitude–longitude combination.
Individual cultivars, or specific blends of cultivars. Casler et al. (2004) combined data from multiple cultivars of each of four ecotype-origin combinations and reported only those means. Some Schmer et al. (2008) data are means of two or three cultivars.



View Full Table | Close Full ViewTable 2.

Mean biomass yield (dry mass, Mg ha−1) for lowland and upland ecotypes of switchgrass in represented plot size classes (m2). Standard deviation, number of observations, and mean plot size within a given plot size class are also given.

 
Plot size class(range, m2) 0–3 3–6 6–9 9–12 12–15 15–18 27–30 36–39 79 147 175.5 >30,000
Lowland
Mean yield (Mg ha−1) 4.2 14.8 17.6 13.8 12.7 12.5 11.8 8.2 na 19.1 14.6 na
(SD) (0.6) (4.9) (4.3) (6.6) (3.5) (5.2) (6.0) (4.3) (11.2) (7.0)
n 2 62 22 188 30 228 30 71 10 9
Mean plot size (m2) 2.4 5.9 7.0 9.7 13.2 17.6 27.3 37.2 147.0 175.5
Upland
Mean yield (Mg ha−1) 11.0 9.2 9.3 6.1 7.1 10.8 na na 8.3 na na 7.2
(SD) (3.4) (4.4) (3.3) (2.9) (2.7) (4.9) (2.7) (2.1)
n 26 100 42 86 78 135 10 29
Mean plot size (m2) 2.8 5.6 7.0 10.9 13.8 17.4 79.0 67,862



View Full Table | Close Full ViewTable 3.

Mean biomass yield (dry mass, Mg ha−1) for lowland and upland switchgrass ecotypes in each of seven nonirrigated land capability classes (LCC). Standard deviation, median, number of observations, and standard error of the mean are also given.

 
LCC 1 2 3 4 5 6 7
Lowland
Mean na 11.4 16.6 12.3 na 16.2 na
(SD) (5.1) (5.8) (4.2) (4.1)
median 11.1 15.7 13.1 16.0
n 283 191 58 56
SEM 0.3 0.4 0.5 0.6
Upland
Mean 10.7 5.9 10.3 7.5 na 9.6 6.3
(SD) (3.6) (2.8) (4.1) (3.7) (4.4) (3.1)
median 10.2 5.5 9.9 6.9 9.3 6.6
n 27 102 163 36 98 48
SEM 0.7 0.3 0.3 0.6 0.4 0.4



View Full Table | Close Full ViewTable 4.

Least-squares estimates of nonlinear model parameters, as defined in Eq. [3–6]. Limits on the 90% confidence interval for each parameter are also given. All parameter estimates are significantly different from zero at the p = 0.05 level. The R 2 value and root mean square error (RMSE) for the full model are also given.

 
Parameter† Estimate Lower 90% CL Upper 90% CL
k low 1.51 1.44 1.59
k opt 0.927 0.795 1.060
k 1 0.028 0.016 0.050
k 2 0.118 0.078 0.176
t opt 14.14 13.50 14.78
k p 0.196 0.177 0.215
k fert 0.0025 0.0017 0.0032
k lat 0.125 0.080 0.171
lat* 38.18 36.60 39.75
R 2 0.34
RMSE 4.62 Mg ha−1