Growth and yield of sweet corn ( Zea mays L.) cultivars in response to planting date and plastic mulch in a short-season environment

Abstract

The optimum soil temperature required for sweet corn ( Zea mays L.) germination is rarely achieved during spring planting in Newfoundland (NL), Canada. Plastic mulches have been used to improve establishment and hasten maturity during the short production season. The effects of cultivar, plastic mulch and planting date on plant growth, yield and quality traits of sweet corn were studied in 2001 and 2002. Two plastic mulch systems: plastic mulch (PM) and no mulch (NM), four sweet corn cultivars: ‘Seneca Arrowhead’, ‘Seneca Daybreak’, ‘Seneca Horizon’, and ‘Northern Supersweet’, and three planting date treatments (PDTs): 1, 15 and 29 May, were used. The experiment was structured as a split split-plot design in a randomized complete block arrangement and four replicates. Temperature data were taken from air and soil (0.05 m depth) both inside and outside the plastic mulch. Air temperatures from 1 m above soil surface were taken to determine cumulative corn heat units (CHU, base 30/10 °C). Maximum air and soil temperatures during the first 4 weeks were up to 20 °C higher under PM than on NM plots. The plots were harvested as corn matured at grain moisture content of between 72 and 78%. There was no year effect on the variables measured. A plastic×planting date×cultivar interaction observed suggests that some cultivars performed better under plastic depending on the planting date. The influence of plastic cover on plant growth was higher at 1 May and 15 May PDTs than at 29 May PDT. When averaged across planting dates, the PM treatment decreased days from planting to emergence (VE) by 3–5 days and correspondingly decreased silking (R1) by 8–17 days and maturity by 7–13 days. The plastic mulch increased total yield and marketable yield by 8–17 and 3–6% over no plastic, respectively. The effects of cultivar and PM treatments on marketable yield and the quality-related traits were not consistent across planting dates, although several of the traits had a favorable response to plastic cover, particularly at 1 May and at 15 May PDTs.