Growers can throw the kitchen sink at corn to increase yield but there’s no guarantee that the extra inputs will improve the bottom line when the crop goes to market.
That was certainly the story Purdue University associate professor and extension corn specialist Dr. Dan Quinn observed in his trials across Michigan, Indiana and Kentucky in 2022 and 2023. And chasing yield with more inputs is even more challenging in a year like 2025 as growers struggle with low corn prices, he stresses.
On this episode of RealAgriculture Corn School, Quinn tells host Bernard Tobin that his research shows little return on investment for many inputs, and most of the yield benefits could be attributed to just one or two specific inputs. Quinn’s intensive management program included in-furrow fungicide, higher seeding rates, sulphur fertilizer, late-season nitrogen and a foliar fungicide at the R1 growth stage.
Overall, the intensive treatment generated an additional 17 bushels per acre, but the cost of the additional inputs was steep — more than $100 per acre. As Quinn dug into the data, however, he noted that two inputs, foliar fungicides at R1 and sulphur, were primarily responsible for the bulk of the yield gain. In both years, the foliar fungicide delivered an additional 16 bushels as it worked to protect the crop from the devastating effects of tar spot, and protect the plant’s ability to photosynthesize and drive late-season grain fill.
The impact of added sulphur (5.2 gal/ac as ATS at V5 sidedress) was not as consistent, but it did deliver an extra 12.9 bushels in 2023 trials. Check out the video below.
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