Evaluating Strip and No-Till Maintenance of Perennial Groundcovers for Annual Grain Production

Perennial groundcover (PGC) merges scalable soil and water conservation with high-yielding row crops, enhancing ecosystem services of annual grain crop production. However, ineffective groundcover suppression increases competition between the groundcover and row crop, reducing row crop grain yield. The objective of this study was to assess the effectiveness of three Kentucky bluegrass (KBG) groundcover suppression methods each at narrow and wide widths on maize (Zea mays L.) growth and development in evenly spaced PGC, compared to alternating PGC swards and a no-PGC conventional tillage control. Suppression methods for evenly spaced PGC included two different strip tillage implements, completing either shallow or deep soil fracture, for mechanical suppression and a banded sprayer for no-tillage chemical suppression. We measured weekly for maize plant height, phenological stage of development, reflected red:far-red (R:FR) ratio, early vegetative and final plant density, grain and stover yield, yield components of kernel rows ear-1, kernels row-1, kernels ear-1, ear length, kernel weight, grass frequency, and weed community. In 2020, maize grain yield in the alternating PGC swards (11.38 Mg ha-1) was similar to the control (12.78 Mg ha-1) and greater than in the evenly spaced groundcover (9.62 Mg ha-1). Maize grain yield was similar for systems in 2021 (7.41 Mg ha-1), due to drought and high coefficient of variation. Weed community was similar for systems in both years. A maize competition response was observed for both suppression widths across methods. Groundcover dormancy may be needed in conjunction with effective chemical and/or mechanical groundcover suppression to support maize production in PGC.