Rye–Vetch Spatial Arrangement and Tillage: Impacts on Soil Nitrogen and Sweet Corn Roots

Abstract

Core Ideas Strip‐tillage decreased soil inorganic N within a rye–vetch organic system, but had minimal effect on sweet corn yield. Strip‐intercropping rye–vetch increased N availability within the crop row of strip‐tillage. Strip‐intercropping rye–vetch decreased root mass within the row, but had no effect on yield or shoot biomass. Strip‐intercropping of functionally diverse cover crops, such as cereal rye (Secale cereal L.; “rye”) and hairy vetch (Vicia villosa Roth; “vetch”), may enhance N use efficiency in reduced‐tillage systems by concentrating N‐rich vetch residue within the subsequent crop row, thereby increasing root access to pools of organic N. We established a field study in southwestern Michigan between 2011 and 2014 to compare the effects of rye–vetch spatial arrangement and tillage on soil N, soil moisture, sweet corn (Zea mays L.) above‐ and belowground biomass, and root morphology. The experiment consisted of a 2 × 2 factorial with two levels of rye–vetch spatial arrangement: segregated into strips (SEG) and full‐width mixture (MIX), and two levels of tillage: strip‐tillage (ST) or full‐width tillage (FWT). Strip‐tillage reduced soil inorganic N compared to FWT in 2 out of 3 yr, but increased soil moisture and sweet corn shoot biomass in 2 out of 3 yr. Segregating rye and vetch into strips increased inorganic N within the crop row, but had minimal impact on sweet corn biomass or yield. In contrast, sweet corn roots were responsive to relatively small changes in the distribution of soil N or moisture resulting from strip‐tillage and segregated plantings. Strip‐tillage and strip‐intercropping show promise in adapting reduced‐till systems for organic production, but future research should evaluate the response of other crops, and adjustments in cover crop species and termination methods to help optimize these practices.