|SAKIROGLU, MUHAMMET - University Of Wisconsin|
|DONG, CHENFEI - Jiangsu Academy Agricultural Sciences|
|Hall, Mary Beth|
|JUNGERS, JACOB - University Of Wisconsin|
|PICASSO, VALENTIN - University Of Wisconsin|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/2/2020
Publication Date: 6/8/2020
Citation: Sakiroglu, M., Dong, C., Hall, M., Jungers, J., Picasso, V. 2020. How does nitrogen and forage harvest affect belowground biomass and non-structural carbohydrates in dual use Kernza intermediate wheatgrass?. Crop Science. 2020;60:2562-2573. https://doi.org/10.1002/csc2.20239.
Interpretive Summary: Perennial crops have potential to reduce erosion, water pollution, and carbon emissions, and cropping inputs as compared to annual crops. All common grain crops are annuals. However, a perennial forage grass, Kernza, may be useful for producing grain for people and forage for animal feed. We found that forage harvest and nitrogen fertilizer applications did not affect the wheatgrass's belowground biomass that it relies upon for regrowth. Forage harvest did not affect grain yield, indicating that Kernza wheatgrass could be a viable dual-use crop. Development of dual-use crops such as Kernza wheatgrass has potential to provide an important food source for people and animals as it improves the environmental impact of cropping the land.
Technical Abstract: Intermediate wheatgrass is a cool-season perennial forage grass, whose grain is commercialized in the US as “Kernza”. Its extensive root system may help reducing soil erosion, water pollution, and carbon emissions. Nitrogen fertilization and forage harvest intensity may affect the belowground biomass and non-structural carbohydrates (NSC) concentrations, which may impact growth in subsequent years. We compared two N doses and two forage harvest treatments in a replicated complete blocks experiment at Arlington, Wisconsin, and St. Paul, Minnesota, USA. Seeds were sown in the fall, Kernza grain was harvested in summer, and rhizomes and roots were sampled in following fall to a depth of 0.1 m over two years. The water-soluble carbohydrates (WSC) accounted for 97 to 99 % of NSC, across plant organs, years, and locations. The WSC concentration was higher in rhizomes than in roots in both years, but WSC mass was higher in roots than rhizomes due to greater root biomass. Nitrogen generally did not change NSC concentrations across years, but reduced WSC in rhizome the second year. Forage harvest did not affect NSC concentrations across locations and years. Belowground biomass to 1 m depth in the fall of the second year averaged 478.3 g per square meter regardless of treatments. Summer forage yield in the following year was positively associated with root biomass in the fall, and grain yield was negatively associated with rhizome starch content. These results suggest that harvesting forage in a Kernza dual-use system is not detrimental to intermediate wheatgrass aboveground and belowground productivity.