ASSESSING THE SUSTAINABILITY OF INTERMEDIATE WHEATGRASS AS A PERENNIAL GRAIN AND FORAGE CROP
Law, Eugene Philip
The sustainability of the global agrifood system is threatened by challenges of providing food security, protecting environmental quality, and mitigating and adapting to climate change. Intermediate wheatgrass [IWG; Thinopyrum intermedium (Host) Barkworth & Dewey], a novel perennial grain crop, hs the potential to improve the environmental sustainability of grain production by improving soil and water quality while also producing grain and forage biomass. Due to lower grain yields than annual grain crops, however, the economic viability of IWG cropping systems is currently uncertain. This dissertation reports the results of research projects that examining IWG cropping systems in central New York, USA, with the goal of identifying factors impacting the agronomic, environmental, and economic potential of these systems. Chapter 1 focuses on the agronomic productivity and weed community structure of IWG grown in monoculture and intercropped with red clover (Trifolium pratense L.) over three years, with organic winter wheat (Triticum aestivum L.) used as a comparable annual grain crop. Grain yield of IWG declined over time and was significantly lower than grain yield of wheat in all years. Weed communities of IWG were dominated by perennial grass weeds by the second year. Intercropping red clover increased forage biomass productivity and reduced weed biomass without impacting grain yield of either crop. In Chapter 2, crop productivity and management data from the IWG and wheat systems were used to perform a multi-criteria assessment of the environmental and economic sustainability. This assessment shows that current IWG grain yields would require substantial price premiums to compete economically with wheat, and that the method of allocating energy usage and GHG emissions to crop products influences how these indicators of environmental sustainability are interpreted. Chapter 3 provides evidence that declines in IWG grain yield are caused by intraspecific competition as crop stand density increases, and that this decline can be mitigated via strip-tillage disturbance after grain harvest. These combined results show that IWG cropping systems have potential to contribute to agricultural sustainability in the northeastern United States, particularly if used for dual-purpose grain and forage production and integrated with high-value livestock and dairy production in the region.
agricultural economics; Kernza; multi-criteria assessment of sustainability; perennial grains; sustainable cropping systems; weed community structure
Gomez, Miguel I.; Ryan, Matthew R.
Soil and Crop Sciences
Ph. D., Soil and Crop Sciences
Doctor of Philosophy
Attribution 4.0 International
dissertation or thesis
Except where otherwise noted, this item's license is described as Attribution 4.0 International