Optimizing Corn and Clover Configurations for a Sustainable Living Mulch System.

Sustainable N fertilizer alternatives are needed for cash crop production to ameliorate reliance on herbicides, reduce soil erosion, and improve water quality.  Living mulch systems have been proposed to meet those objectives but capitalizing on the living mulch system requires an understanding of how the cash and mulch crops interact.  White clover (Trifolium repens L.) can be used to produce corn (Zea mays L.) in a living mulch system.  Bands of clover must be killed to successfully establish corn but corn row and band width configurations must be optimized to sustain the system.  The objectives of this study were to determine the effect of corn row and clover band widths on pre- and post-harvest binary corn and clover growth and potentially mineralizable N release from clover when planted at two corn population densities.  Both corn and clover growth increased until 40 days after planting (DAP) after which corn height resulted in shading that decreased clover biomass.  Clover N release increased from 40 DAP until corn harvest.  Corn yield was not affected by clover band width or corn row spacing, but yield was lower at lower population densities.  Post-harvest clover regrowth was affected by both clover band width and the corn row spacing.  Results from this study have been used to design experiments to investigate various ecosystem services provided by the living mulch system.