ALMANAC Model May Help Predict Crops' Role in Bioenergy
Production By Don
Comis December 10, 2008
A computer model called ALMANAC promises to provide answers about a
key issue facing agriculture today: the management of crops such as corn and
switchgrass for bioenergy production.
Agricultural Research Service
Kiniry at the
Soil and Water Research Laboratory in Temple, Tex., and his colleagues
originally developed ALMANAC as a crop-management tool, then updated it as a
pasture management tool. Now it's being used to evaluate biofuel crops.
After its development in Texas, the model was tested in northern
states in 2005. It accurately predicted switchgrass yields in 10 fields in
North Dakota, South Dakota and Nebraska. The model's predicted yields each year
were within 1 to 10 percent of actual yields over all fields.
In another study with northern and southern populations of upland and
lowland switchgrass, the model showed realistic simulated yields in Wisconsin,
Kansas and Oklahoma. In these two studies, the measured yields ranged up to 6.7
tons per acre.
Kiniry and colleagues simulated growing corn and four varieties of
switchgrass in the southern and northern Great Plains and the Corn Belt.
ALMANAC projected that switchgrass would use only half as much water per pound
of material produced as corn grown for grain.
ALMANAC's estimated switchgrass water-use advantage was reduced when
model inputs specified that entire corn plants were to be used for ethanol
production rather than just the grain. In this way, ALMANAC helps farmers
determine the most appropriate crop for their fields under current market and
By predicting outcomes on arid rangeland, marginal lands and more
fertile lands like the Corn Belt, ALMANAC can help farmers alleviate concerns
about shifting acres from food to fuel.
Kiniry's team also used the model to predict the benefits of
anticipated breeding improvements in switchgrass. They found new varieties
might increase yields 2 to 16 percent and water use efficiency by 2 to 7
ALMANAC is online at:
ARS is a scientific research agency in the
U.S. Department of Agriculture.