Effect of increasing levels of maize (Zea mays L.) residue on no-till soybean (Glycine max Merr.) in Northern production regions: A review

• Maize residues on the soil surface are perceived to interfere with soybean performance.
• Maize residues on the soil surface have increased over the years.
• Residues have increased because of several factors.
• Maize residue alters soil properties, soybean nodulation and planter performance.
• Strategies exist to mitigate the effects of maize residues on soybean performance.

In northern temperate regions, such as the northern mid-west, USA and the province of Ontario, Canada, soybean is a common annual row crop for which no-till production has been encouraged for environmental benefit. Soybean is commonly grown in rotation following maize. Increasing maize yield has been implicated as the primary reason why the practice of no-till soybean is declining relative to conventional and reduced tillage systems. In these regions, maize yield has substantially increased during the last decade resulting in greater maize residue. In the following review, we provide evidence that maize residue levels at soybean planting may be increasing, not just due to increasing maize yields, but to changes in the cropping system of these regions. Maize residue levels may increase due to reductions in decomposition before soybean planting because of higher adoption of full-season maize and soybean cultivars, potential limitations in nitrogen available for decomposition, and changes in maize residue quality such as the introduction of Bt maize hybrids. A further review of the literature demonstrates that greater amounts of maize residue could negatively affect no-till soybean production in Northern regions by impacting soil nitrogen and soybean nodulation, soybean emergence, growth and development, as well as impacting soil physical properties such as moisture and temperature. Finally, we review potential strategies that could be employed to address high levels of maize residues for soybean planted with no-till.