Maize performance in a kura clover living mulch under drought conditions

Authors: ALEXANDER, JONATHAN - University Of Minnesota; Baker, John; Venterea, Rodney - Rod

Submitted to: Agrosystems, Geosciences & Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/13/2022
Publication Date: 1/1/2023
Citation: Alexander, J., Baker, J.M., Venterea, R.T. 2023. Maize performance in a kura clover living mulch under drought conditions. Agrosystems, Geosciences & Environment. 6(1). Article e20329. https://doi.org/10.1002/agg2.20329.
DOI: https://doi.org/10.1002/agg2.20329

Interpretive Summary: The kura clover living mulch system (KCLM) is a method for maintaining continuous living cover in annual crop (e.g. corn) production by planting the annual crop into a perennial stand of kura clover. A major challenge in this system is establishing a clear row in the clover in which corn can be planted in a way to minimize competition with the clover. This is typically done with either herbicide or some form of strip or zone tillage. We evaluated the effect of row establishment method and fertilizer N treatment on both the yield and nitrogen use efficiency of corn in KCLM at two sites, Rosemount, MN and Arlington, WI. The three row establishment methods studied were rotary zone tillage (RZT), shank strip-tillage (ST), and banded herbicides (BH), each evaluated at six N rates from 0 to 225 kg N ha-1. The study period was characterized by extended periods of moderate and severe drought. The site most severely affected by drought experienced a near total crop failure, with average maize grain yields of 3.6 Mg ha-1, while the site under moderate drought conditions produced yields that matched expectations for the area (10 Mg ha-1). Row establishment effects on grain yield were different at the two sites. Under severe drought conditions, BH maximized maize yield, while under moderate drought conditions, the higher level of tillage (RZT) maximized maize yield. These responses are most likely due to reduced moisture loss in the row-zone of the BH treatment and the greater level of clover suppression in the RZT treatment. These results suggest that optimal management of KCLM should be based on spring environmental conditions and weather expectations for the growing season.

Technical Abstract: Row establishment for maize production in a kura clover living mulch (KCLM) is important to reduce competition between the living mulch and maize seedlings. Methods that have been used include banded herbicide and various forms of zone tillage. This study investigated the effect of row-establishment and fertilizer N rate treatments on maize yield and nitrogen use efficiency in a KCLM system. Row establishment treatments included rotary zone tillage (RZT), shank strip-tillage (ST), and banded herbicides (BH), each evaluated at six N rates from 0 to 225 kg N ha-1. Challenging environmental conditions were experienced during the study period, with extended periods of moderate and severe drought. The site most severely affected by drought experienced a near total crop failure, yielding average maize grain yields of 3.6 Mg ha-1, while the site under moderate drought conditions produced yields that matched expectations for the area (10 Mg ha-1). Row establishment affected maize grain yield differentially at each site, where, under severe drought conditions, BH maximized maize yield, while under moderate drought conditions, the higher level of tillage (RZT) maximized maize yield. These responses are most likely attributed to reduced moisture loss in the row-zone of the BH treatment and the greater level of clover suppression in the RZT treatment. Results from this study indicate that optimal management of KCLM should be considered with spring environmental conditions and the expected weather outlook.