Productivity of intermediate wheatgrass responds more to local soil and climate factors than fertility treatments in the first establishment year.

Authors: CASSANI, TOMAS - The Land Institute; GUTKNECHT, JESSICA - University Of Minnesota; BASCHE, ANDREA - University Of Nebraska; BRUNSELL, NATE - University Of Nebraska; CREWS, TIM - The Land Institute; CULMAN, STEVEN - Washington State University; DEISS, LEONARDO - The Ohio State University; Laboski, Carrie; PICASSO, VALENTIN - University Of Wisconsin; PINTO, PRISCILA - University Of Wisconsin; REBESQUINI, ROBERTA - University Of Nebraska; TAUTGES, NICOLE - Michael Fields Agricultural Institute; VAN DER POL, LAURA - The Land Institute; JUNGERS, JACOB - Minnesota State University

Submitted to: Frontiers in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/24/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: The intensive cultivation practices of annual cereal crops are causing unprecedented degradation of natural resources. Intermediate wheat grass (IWG) is a perennial dual purpose crop where both grain and forage can be harvested. Perennial crops such as IWG could provide numerous benefits to address these issues, but there is still little comprehensive information about the establishment, fertilization needs, or range of IWG productivity on a regional basis. Across six locations in Kansas, Minnesota, Nebraska, Ohio, and Wisconsin (2 sites), we learned that application of 135 Kg ha-1 N in the first-year resulted in greater summer and fall forage yield, but grain yield was not effected by N application rate. We also found that grain and forage yields varied greatly between locations, and that a combination of local edaphic soil and climate factors explained over 70% of the variance in those differences. In addition, environmental factors, such as the timing and amount of precipitation, evapotranspiration, and soil characteristics, significantly impact IWG yields and these factors should be taken into consideration for setting expectations of regional and annual variation experienced by growers and researchers.

Technical Abstract: The intensive cultivation practices of annual cereal crops are causing unprecedented degradation of natural resources. Perennial crops such as intermediate wheatgrass (IWG) could provide numerous benefits to address these issues, but there is still little comprehensive information about the establishment, fertilization needs, or range of IWG productivity on a regional basis. The objective of this study was to evaluate how IWG establishment and first-year grain and forage yields varied across soil, climate conditions and in response ten treatments across site specific soil and climate characteristics at six locations in the Midwestern USA. The 10 fertilization treatments included N fertilizer rates (0, 45, 90, 135, or 180 Kg ha-1 N, 0 P with 90 Kg ha-1 N or 0 K with 90 Kg ha-1 N), timing (90 Kg ha-1 N as a fall application, spring application, or split application), and source (organic N in 1 treatment, all others with urea as a mineral N source). We found that fertilization influenced summer and fall forage yields but not grain yields. We also found that grain and forage yields varied greatly between locations, and that a combination of local edaphic soil and climate factors explained over 70% of the variance in those differences. Regarding climate, the accumulated precipitation in the 60 days before anthesis explained the most variance in grain and summer forage yields, while the accumulated precipitation from May through October explained the most variation in fall forage yields. In addition, environmental factors, such as the timing and amount of precipitation, evapotranspiration, and soil characteristics, significantly impact IWG yields and these factors should be taken into consideration for setting expectations of regional and annual variation experienced by growers and researchers.