An intermediate perennial wheatgrass has attracted growing interest from researchers and farmers. It can be used as grain or as forage.
Tim Crews is director of research and lead scientist for the ecology program at The Land Institute of Salina, Kansas. He has been studying nitrogen fertility in the wheatgrass, to be marketed as Kernza. He's looking at Kernza-legume intercropping systems where the legume supplies nitrogen to Kernza.
Crews is working to quantify nitrogen fixation and transfer in Kernza-alfalfa systems and longer-term changes in soil organic-nitrogen reserves. Interseeding the crops could reduce the amount of synthetic nitrogen fertilizer needed, but more research is needed. The Land Institute is using isotopes to determine the depth at which nitrogen is taken up by Kernza in different seasons. Kernza’s roots can reach lengths of as much as 10 feet.
What once was considered pubescent wheatgrass is densely covered with hairs, whereas intermediate wheatgrass has vegetative structures that are for the most part smooth, according to the U.S. Department of Agriculture. The previously recognized separate species of intermediate and pubescent wheatgrass are now recognized as one species, Thinopyrum intermedium. Intermediate wheatgrass grows to 3 to 4 feet tall. It’s a long-lived cool-season grass with short rhizomes and a deep-feeding root system. The seed spikes may be 4 to 8 inches long. Leaves are green to blue-green in color and sometimes drooping. The lemmas, paleas and glumes are smooth to pubescent. There are usually fewer than seven florets. Commercial seed of intermediate wheatgrass often contains both pubescent and glabrous forms.
University of Manitoba researchers in Canada are studying Kernza’s nitrogen cycling and several other of the crop’s ecosystem services. They are evaluating the economic potential of a crop-livestock system based on Kernza and several other aspects of the crop. Their findings are expected to shed light on challenges such as the need for synthetic fertilizer inputs for late-fall or early-winter cattle grazing.
The Cornell University-Sustainable Cropping Systems Laboratory is studying interseeding Kernza with red clover. Researchers there are studying if the legume could provide enough fertility for a Kernza crop. They will study whether transitioning annual grain-crop fields to perennial grain-crop fields would increase soil health. They also will explore whether intercropping would reduce the need for nitrogen inputs compared to fields with Kernza alone.
Field studies and modeling activities at the University of Minnesota indicate Kernza is more efficient than corn at absorbing nitrogen. Early tests with Kernza have shown little to no nitrogen leaching out of the fields.
Visit landinstitute.org or blogs.cornell.edu/scslab -- see perennial grains -- or perennialecology.com or sustainablecropping.umn.edu/kernza or www.nrcs.usda.gov -- search for "intermediate wheatgrass" -- for more information.