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Phytotechnology with Biomass Production
in southern Nebraska (~41 N latitude) at over 17 t ha −1 , near 34 t ha −1 biomass,
with contest winners exceeding 19 t ha −1 of grain (NCGA, 2019).
Miscanthus yields may be higher in temperate zones of southern Europe,
e.g., Croatia northward (~45 N latitude), where longer daylength promotes
summer growth and delays flowering of M. × giganteus if water is not limiting. On the other hand, yields of M. × giganteus in the US are not generally
higher in southern states, below ~30 N latitude, where daylength is shorter
sooner, even when rainfall and soil fertility are not limiting. Lee et al. (2018)
provide results for maintenance stages of M. × giganteus production in comparison with other biomass energy crops (selected cultivars of switchgrass,
sorghum, and sugarcane) in the U.S. Rainfall, and in some cases fertilizer
application, affected productivity at most sites, after successful establishment. Productivity was most variable in Mead Nebraska (~41.2 N latitude),
ranging from 15 to 35 Mg ha −1 , while other sites had intermediate but more
stable yields. This was primarily a function of variable rainfall in Nebraska
plus a variable long growing season.
Lee et al. (2017) reported a strong interaction of water availability and N
fertilization at Urbana, IL (~40 N latitude). For an established study (from 2008
to 2009) yields declined in a droughted summer of 2012 for the unfertilized
plots while remaining relatively high and stable with N fertilization at 60 kg
ha −1 year −1 . Plots were 10 × 10 m and 100 plants, with four replicates of each
treatment. Water availability was extremely reduced, 68% and 90% below historic averages over 2 months, June and July in 2012, August and September in
2013. Yields for 0 kg ha −1 added N vs 60 kg ha −1 were: in 2011, 15.9 vs 23.3 Mg
kg ha −1 ; in 2012, 11.6 vs 24.8; in 2013, 15.3 vs 28.8; in 2014, 8.5 vs 25.9. The low
rainfall in 2013 continued throughout the remainder of the year at <1/2 of the
30-year average (28 vs 61 cm) for the latter half of the year. Although rainfall
in 2014 was above average, the unfertilized plot may have been unable to take
advantage of that abundance. Averaged over the 4 years, yield in the fertilized
plots was double that of the unfertilized (25.5 vs 12.8 Mg ha −1 year −1 ).
It should be noted, however, that Lee et al. (2018) reported rather different
yield data for experiments with the same treatment design at the same, or
a very nearby location. For instance, in 2014 the unfertilized plots yielded
the same as in 2013, while in 2012 yields of both unfertilized and fertilized
plots were about half of their respective yields in 2013. Neither paper offers
any comment on the large apparent differences. Sampling of biomass yield
seems to have been done differently in the two studies. Lee et al. (2017) used
five 1 m 2 quadrats per plot while Lee et al. (2018) used one 4 m 2 sample at the
center of the 10 × 10 m plot. Even with such a large sample, some replicates
in some years varied from others within a treatment, by more than two-fold
as shown in their supplemental data. These results indicate that interpreting
Miscanthus yields in terms of known variables such as rainfall is challenging.
In a dry summer Mediterranean climate (Sicily) restoring 25% (~15 cm)
or 75% (~45 cm) potential evapotranspiration water by irrigation increased
yields of both Arundo donax and M. × giganteus energy crops studied by
Phytotechnology with Biomass Production
in southern Nebraska (~41 N latitude) at over 17 t ha −1 , near 34 t ha −1 biomass,
with contest winners exceeding 19 t ha −1 of grain (NCGA, 2019).
Miscanthus yields may be higher in temperate zones of southern Europe,
e.g., Croatia northward (~45 N latitude), where longer daylength promotes
summer growth and delays flowering of M. × giganteus if water is not limiting. On the other hand, yields of M. × giganteus in the US are not generally
higher in southern states, below ~30 N latitude, where daylength is shorter
sooner, even when rainfall and soil fertility are not limiting. Lee et al. (2018)
provide results for maintenance stages of M. × giganteus production in comparison with other biomass energy crops (selected cultivars of switchgrass,
sorghum, and sugarcane) in the U.S. Rainfall, and in some cases fertilizer
application, affected productivity at most sites, after successful establishment. Productivity was most variable in Mead Nebraska (~41.2 N latitude),
ranging from 15 to 35 Mg ha −1 , while other sites had intermediate but more
stable yields. This was primarily a function of variable rainfall in Nebraska
plus a variable long growing season.
Lee et al. (2017) reported a strong interaction of water availability and N
fertilization at Urbana, IL (~40 N latitude). For an established study (from 2008
to 2009) yields declined in a droughted summer of 2012 for the unfertilized
plots while remaining relatively high and stable with N fertilization at 60 kg
ha −1 year −1 . Plots were 10 × 10 m and 100 plants, with four replicates of each
treatment. Water availability was extremely reduced, 68% and 90% below historic averages over 2 months, June and July in 2012, August and September in
2013. Yields for 0 kg ha −1 added N vs 60 kg ha −1 were: in 2011, 15.9 vs 23.3 Mg
kg ha −1 ; in 2012, 11.6 vs 24.8; in 2013, 15.3 vs 28.8; in 2014, 8.5 vs 25.9. The low
rainfall in 2013 continued throughout the remainder of the year at <1/2 of the
30-year average (28 vs 61 cm) for the latter half of the year. Although rainfall
in 2014 was above average, the unfertilized plot may have been unable to take
advantage of that abundance. Averaged over the 4 years, yield in the fertilized
plots was double that of the unfertilized (25.5 vs 12.8 Mg ha −1 year −1 ).
It should be noted, however, that Lee et al. (2018) reported rather different
yield data for experiments with the same treatment design at the same, or
a very nearby location. For instance, in 2014 the unfertilized plots yielded
the same as in 2013, while in 2012 yields of both unfertilized and fertilized
plots were about half of their respective yields in 2013. Neither paper offers
any comment on the large apparent differences. Sampling of biomass yield
seems to have been done differently in the two studies. Lee et al. (2017) used
five 1 m 2 quadrats per plot while Lee et al. (2018) used one 4 m 2 sample at the
center of the 10 × 10 m plot. Even with such a large sample, some replicates
in some years varied from others within a treatment, by more than two-fold
as shown in their supplemental data. These results indicate that interpreting
Miscanthus yields in terms of known variables such as rainfall is challenging.
In a dry summer Mediterranean climate (Sicily) restoring 25% (~15 cm)
or 75% (~45 cm) potential evapotranspiration water by irrigation increased
yields of both Arundo donax and M. × giganteus energy crops studied by