ASHS 2015 Annual Conference

Five supersweet (sh2) processing sweet corn varieties were tested at populations of 120%, 100%, 80%, 60%, and 40% of standard population (57,400 plants/ha). Two trials were planted with the same treatments; one on April 20, 2012, and one on May 16, 2012, and data was collected yield in terms of ears per acre, weight of unhusked ears per acre, and cut corn yield. 'Overland' and GSS 1453 were able to compensate for stand loss in terms of tonnage and, even more so, in terms of cut corn yield—even with population densities that were 40% of standard planting density. Of these two varieties, Overland had higher overall yields in the trials. 'SS Jubilee Plus' also compensated well for reduced stand. 'Protégé' compensated for stand loss up to 60% of standard population density, but produced significantly lower yields in terms of cut corn and tonnage at 40% of standard population density. GSS 2259P did not compensate for stand loss effectively and produced its highest yields in terms of tonnage and cut corn at 120% of the standard population density (68,900 plants/ha), which suggests that it should be planted at a higher density to obtain maximum yield. Reduced stands did not significantly affect time to maturity of the varieties tested.  In another study on gaps in stands, there were no differences in yield between evenly reduced stands and those with irregularly spaced gaps with lengths of up to 2 m. Based on the results of these experiments, yield loss from stand reduction can be estimated based solely on plant population density, without consideration for unevenness in spacing if gap sizes are less than 2 m.  Processing sweet corn nitrogen rate studies in 2012 and 2013 showed that yield was maximized at 196 kg/ha N and maximum economic yield was at 168 kg/ha N.  In 2014 the maximum economic yield was found at 224 kg/ha N.  Tillage studies from 2012–2014 showed that early spring planting (April) sh2 processing sweet corn varieties were best adapted to conventional tillage when compared to vertical tillage or no-till.  An average yield reductions of 18% was found in no-till compared to conventional tillage when planted after a winter-killed forage radish cover crop.  July planted sweet corn planted after wheat was equivalent across all tillage treatments: no-till, strip till, vertical till, and conventional till in 2012 and 2013.  In 2014, conventional treatments yielded significantly higher than the other tillage treatments.