Calcium Products - Corn Yield Response to SuperCal SO4
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Corn Yield Response to SuperCal SO4

Corn Yield Response to SuperCal SO4

Location:         Northern/NE Iowa

Date:              2006 - 2008

Crop:              Corn

Treatments:    Initial: 40 lbs S/acre (SuperCal SO4 @ 235 lbs/A)

                     Follow-up: 10, 20, 40 lbs S/acre (SuperCal SO4 @ 60, 117, 235 lbs/A)

 Initial Trial (Sawyer et al., 2011)

Trials were initiated in 2006 (Sawyer et al., 2011) to evaluate yield response in corn, where five out of six sites showed a yield increase that averaged 38 bu/A from SuperCal SO4 applied at 235 lbs/A. Sites were chosen based on visibly sulfur deficient corn and applications were top-dressed. Corn plants showed a quick response with rainfall after SuperCal SO4 application.

Follow-Up Trials (Sawyer et al., 2011)

Due to the response from the initial trials, 45 trial sites in north-central to northeast Iowa were established in 2007 and 2008 to determine corn response to S rate. These sites were selected to represent major soils, cropping systems, and a range in potential S response. SuperCal SO4 was surface applied without incorporation after planting at 60, 117, and 235 lbs/A. Yield was increased with SuperCal SO4 applications at 17 of 20 sites in 2007 and 11 of 25 sites in 2008. Across all sites, yield increase averaged 13 bu/A. When analyzed by responsive sites, the maximum SuperCal SO4 response rate for fine-textured soils was 100 lbs/A, while coarse-textured soils showed maximum yield with 150 lbs/A.

One very interesting result from this study was showing that SO4-S soil testing does not always determine if a yield response will result from S application. Concentrations above 10 ppm are generally considered sufficient, but some of the sites in this trial showed yield response even when the soil test for SO4-S was above 10 ppm. These results highlight the complex influence of many factors (environment, soil, and crops) that result in sulfur availability over a growing season. Visual observation of sulfur deficiency can lead to correct determination of S response.

Overall, this research indicates a need for a paradigm shift in S fertilization, which has historically been an overlooked nutrient in corn. Make the smart choice for your corn and apply SuperCal SO4 to meet your crop’s sulfur needs!


Sulfur Fertilization Response in Iowa Corn Production

Additional Info

  • Article Reference:: Calcium Products, Inc.
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