Geographic information systems show impact of field placement on sh2 sweet corn stand establishment

The objective of this study was to ascertain if stand establishment of sh2 sweet corn (Zea mays L.) would benefit from variable planting depths determined by the use of geographic information systems (GIS). Spring and fall research plots were established in a field [80 x 20 m (262 x 66 ft)] containing Crosby silt loam and Kokomo silty day loam soil series in Columbus, Ohio. Three sh2 sweet corn cultivars (Starship, Skyline, and Confection) were planted at three depths on the two soil types in the fall study, with an additional transition soil added in the spring. Emergence counts as well as soil moisture and temperature were monitored. In the spring, sites were also sampled for nutrient levels and soil compaction. Significant variability was found within the field with respect to soil moisture, temperature, nutrient levels, and compaction. Seedling emergence fluctuated with average soil moisture increasing in blocks with up to 24% moisture and then leveling off. Daily minimum soil temperatures impacted stand establishment. Although heat units accumulated faster on the Crosby soil, emergence was slower and less complete on these soil series than on Kokomo soil series. Further investigation determined that although temperatures of the Crosby soil were 3 to 4.5 degrees C (5.4 to 8.1 degrees F) warmer during the day than the Kokomo soil, temperatures on the Crosby soil averaged 2 degrees C (3.6 degrees F) cooler at night. Analysis of emergence patterns and field variability was performed on ArcView mapping software. Although 'Skyline' planted at 2 cm (0.8 inches) had the best emergence overall, final stand would have been increased with 'Skyline' planted variably at 2 and 4 cm (1.6 inches). Mapping the field under these different scenarios showed that although area with less than 70% stand would exist with a 2-cm uniform planting depth, the entire field would have a stand of 70% or greater with variable planting depth using a high vigor seedlot.