Perennial Grain Polycultures:
Mimicking Ecosystem in Production
Dan Kamen
Food Fiber and Pharmaceuticals
Annual Agriculture
•  2/3 of agriculture relies on monocultures of
monocarpic grain crops
–  Soil erosion
–  Inefficient irrigation
–  Pesticide run off / poisons communities
–  Fertilizer run off / eutrophication,
contamination
–  Carbon released by replacing ecosystem with
agriculture / by fertilizers / irrigation, etc.
Perennialism
•  Most ecosystems are characterized by
communities of perennial plants
–  The Great Plains of the United States were
characterized by a tall grass prairie
–  Perennials maintain root systems year-round
•  Hold soil together.
•  Uptake nutrients and water more efficiently (30-50xAnnual).
–  Why not try to take advantage of these benefits in
agriculture?
Fig 1. Comparison of root systems. Annual wheat on left, intermediate
on the right, at four times of the year. (Glover et al., 2007)
Research at the Land Institute
•  Founded by Wes and Dana Jackson in
in 1976; Salina, KS.
•  Toward a “Natural Systems Agriculture”
•  Plan to have perennial grain crops
ready for agriculture in 25-50 years.
•  How are they doing it?
Perennial Grain Polycultures
•  To mimic prairie grass community, need:
–  1. warm season perennial grasses
–  2. cool season perennial grasses
–  3. perennial legumes (Fabaceae)
–  4. perennial sunflowers (Asteraceae)
•  Domesticate novel species, or hybridize
annual grain crops with perennial relatives
Possible Perennial Grains,
Identified by Land Institute
1. Warm season perennial grasses:
Tsvelev, Mammoth Wildrye (Leymus racemosus; Poaceae)
Intermediate wheatgrass (Thinopyrum intermedium; Poaceae)
2. Cool season perennial grasses:
Eastern Gamma Grass, (Tripsacum dactyloides; Poaceae)
Hybrid Grain Sorghum (Sorghum x halapense; Poaceae)
3. Perennial legumes
Wild Senna (Cassia marilandica; Fabaceae)
Illinois Bundleflower (Desmanthus illinoensis; Fabaceae)
4. Perennial sunflowers
Maximilian Sunflower (Helianthus maximiliani; Asteraceae)
Problems and Obstacles
•  Can perennials produce sufficient yields?
Table 1. (Cox et al., 2006).
Cox, T.S., et al. (2006) Prospects for Developing Perennial
Grain Crops. BioScience 56(8):649-659.
Glover, J. G. (2003) Characteristics of Annual vs Perennial Systems
Sod Based Cropping System Conference, University of Florida’s
Institute of Food and Agricultural Sciences.
Jackson, W. and L. L. Jackson. 1999. Developing high seed
yielding perennial polycultures as a mimic of mid-grass prairie.
Pp. 1-55 in Agriculture as a Mimic of Natural Ecosystems.
Kluwer Academic Publishers, Boston.