Tall Native Prairie Grasses Give Good Alcohol Yields

North America is rich with open land which is neither forest nor farmland. Native grasses and other plants grow wild and lush on such lands. This growth represents a potential harvest of cellulosic ethanol crops, without any potential for affecting food yields, depleting forests, or adversely affecting soil quality.

Now a study by Agricultural Research Service (ARS) scientists indicates that plant species diversity and composition are key factors in potential energy yield per acre from biomass harvested from CRP (Conservation Reserve Program) land.

...CRP grasslands with the highest number of species had the lowest potential ethanol yields per acre. But sites dominated by a small number of native tall prairie grass species, such as switchgrass, big bluestem, and indiangrass, had the highest yields.

...This extensive study also shows that CRP lands in the northeastern United States with a high proportion of tall native prairie grasses have the potential to produce more than 600 gallons of ethanol per acre. This energy can be produced while maintaining the ecological benefits of CRP grasslands. _Bioenergy

The interspersing of other native crops along with native prairie grasses can have added benefits for the soil and for biofuels yields. Take the native Cup plant, for example:

Cup plant is likely to increase biodiversity in a plant community because it attracts a variety of insects and even birds. Goldfinches drink out of the leaves, and the stems provide perch areas for grassland birds.

...Perennial grasses will always be the base for biomass production, but cup plant is a complementary species, scientists say. Increasing number of species in the mix reduces probability of plant disease and insect pests attacking one species and causing large losses in yield. _SD

Monocultures tend to attract pests which specialise in the infestation of that one particular crop. Multiple plants growing synergistically together are less prone to that problem, and will be less likely to require insecticides, herbicides, and other expensive supplementals.

The same consideration applies for cultures of microbial species, of course. Synergistic multi-species cultures of microbes are almost certain to become the long term approach to microbial energy industries. But it will take some time for the old mono-culture school of biology and agriculture to die off.