Side‐dressing liquid manure into standing corn increases grain yield while maintaining post‐harvest soil nutrient status

In the US Midwest, liquid manure is most commonly applied on bare soil after fall crop harvest, increasing the risk of nutrient loss during winter and early spring. Applying manure as a side‐dress into standing corn ( Zea mays L.) using tankers or soft drag hose systems can better match seasonal plant N uptake, but producers need evidence that this practice maintains crop yields and reduces excess nitrogen (N) in the soil after harvest. We evaluated paired, on‐farm strip trials across corn fields in Ohio (five counties) during 2022–2023, comparing synthetic fertilizer management with side‐dressed liquid hog (swine) manure. Trials were in a randomized complete block design with three replicates at eight on‐farm sites. Soils (0–20 cm) were sampled pre‐application (Early Season) and post‐harvest (Late Season). Across sites, side‐dressed manure increased corn grain yield by 8.5% on average relative to fertilizer ( p = 0.06) with 12% less first‐year available N that more closely matched seasonal crop N demand and reduced the window for environmental losses relative to fall application. Ear‐leaf nutrients remained unchanged between practices, indicating manure maintained corn nutritional status. Most soil nutrients and soil health indicators were not affected by treatment × sampling time interaction, indicating that side‐dressed manure improved yield without increasing post‐harvest topsoil nutrient surpluses, with exception of side‐dress manure showing higher zinc after corn harvest. Overall, in‐season manure side‐dressing can enhance corn productivity while maintaining post‐harvest topsoil nutrient status under working‐farm conditions.