Mechanical termination of a perennial grain crop minimally impacts soil structure, carbon and carbon dioxide emissions

• Published in: Journal of sustainable agriculture and environment 2024-03, Vol.3 (1), p.n/a
• Main Authors: Kundert, Jacob, Rakkar, Manbir, Gutknecht, Jessica, Jungers, Jacob
• Format: Article
• Language: English
• Subjects: greenhouse gas emissions; intermediate wheatgrass; Kernza; soil health; tillage
• ISSN: 2767-035X; 2767-035X
• DOI: 10.1002/sae2.12094

Introduction Mechanical termination of crops can negatively affect soil biological, chemical, and structural characteristics. Perennial crops do not require annual termination and can improve these same soil characteristics, which has catalysed interest in the development of new perennial crops. Advanced lines of the perennial grass intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth and Dewey; IWG) have been bred for increased seed size and marketed as Kernza® perennial grain, but little is known about how this new crop can be terminated for subsequent annual crop production in rotations that enhance agricultural productivity and environmental sustainability. Materials and Methods Five methods of terminating IWG were tested in Minnesota, USA. Treatments included mechanical tillage using a chisel plow (CHI), undercutter (UND), and disc (DSC), along with no‐till treatments of glyphosate (GLY) and a repeated‐mowing control (CTRL). Treatment effects on IWG mortality, soil carbon dioxide (CO2) emissions, bulk density, aggregate stability, soil carbon stocks and soybean yield were measured. Results Daily CO2 fluxes differed by treatment (p