Early-planted fresh market sweet corn (Zea mays) is prone to nonuniform ear length and quality due to uneven germination in cool soils. Growers compensate by reducing in-row spacing at seeding, to increase final plant stand. This risk management strategy was suspected to be reducing quality of early-planted sweet corn, based upon buyer feedback. Four experiments were conducted in upstate New York, to examine the effects of in-row spacing and cultivar on early-planted sweet corn ear yield, length and uniformity. Cultivars examined included `Temptation' (4 years), `Sweet Symphony' (3 years) and `Seneca Spring' (2 years). In-row spacings tested ranged from 6 to 9 inches (15.2 to 22.9 cm), using a 30-inch (76.2-cm) between-row spacing. In-row spacing and cultivar influenced marketable yield, husked ear weight and length of early-planted corn, but the extent varied by year. Despite improvements in individual ear weight and length at wider in-row spacing, marketable yield was usually higher at more narrow spacings. Increases in ear weight at wider spacings were usually associated with increases in weight of the outer, green husk. Average ear length of a cultivar varied between 0.2 and 0.6 inches (0.5 to 1.5 cm) in response to spacing. If ears longer than 7 inches (17.8 cm) were desired, 40% to 60% of ears satisfied this criteria if harvested from plants grown at 8-inch (20.3-cm) in-row spacing or a plant population of 26,000 plants/acre (64,200 plants/ha). Ear weight and length of `Seneca Spring' was not as affected by the in-row spacing treatments compared to the other two cultivars, perhaps due to the small size of this cultivar. Selection of smaller sized sweet corn cultivars for planting at high plant populations (6-inch in-row spacing) may reduce the variation in ear weight under challenging early season conditions. For cultivars with similar growth characteristics and maturities of `Temptation' and `Sweet Symphony,' a minimum in-row spacing of 8 to 9 inches or a plant population of 23,200 to 26,000 plants/acre (57,300 to 64,200 plants/ha) was recommended to minimize variation in ear yield and quality from first bareground plantings in the northeastern United States.
Anusuya Rangarajan, Betsy Ingall, Michael Orfanedes and David Wolfe
Anusuya Rangarajan, Betsy A. Ingall and Michael S. Orfanedes
Early fresh-market sweet corn expressed concern is prone to variability in ear length and quality due to uneven germination rates in cooler soils, smaller plant size of early corn, and single ear per stalk trait of early varieties. In an informal survey of current practices, growers reported using in-row spacings between 0.5 and 0.25 m (0.76 m between rows) for their first bare-ground corn, representing a range of plant populations from 86,000 to 43,000 plants/ha. However, no information had been gathered on the impacts of these various in-row spacings on early corn ear length and overall quality and how different sweet corn types (se, sh2, sweet breeds) might respond to these spacings under cool conditions of early spring. Four trials were conducted over the last 2 years, in upstate New York, examining three sweet corn types, five plant populations, and two nitrogen sidedress rates for effect ear length, quality, and uniformity. In general, results thus far indicate that all three parameters can influence ear quality and variability. Among treatments, ear length varied by up to 1 cm. The variety `Sweet Symphony' was less affected by high populations than `Temptation'. In 1998, no difference in ear length due to spacing was found. It is suspected that the warm spring in 1998, coupled with adequate moisture, reduced plant stress during early growth. Higher nitrogen sidedress rates reduced variability of early season corn, at all populations. In 1999, plant population was found to be the most important factor affecting ear physical characteristics.