Transplanted maize (Zea mays) for grain production in southern England. I. Effects of planting date, transplant age at planting and cultivar on grain yield

Abstract

Agroclimatic conditions in the UK are not ideally suited to maize (Zea mays L.) as a grain crop. An alternative growing technique to direct-seeded maize was investigated at Reading University over three growing seasons, using four cultivars (Bastion, Ace, Anko and Mirna) of different FAO maturity ratings. In the main trials conducted in 1989 and 1990, seedlings were raised for 15–45 days in a glasshouse and planted in the field between early May and mid-June, at 10 plants/m². On each planting date, maize kernels of the same cultivars were also sown in the field. At the end of each growing season, transplanted and direct-seeded crops were assessed for grain maturity and grain yield components. Averaged over year and cultivar, transplants matured significantly earlier than direct-seeded maize and tended to give higher grain yields. Their grain dry weights (86% DM) averaged 7·0 t/ha in a preliminary study in 1988, 9·0 t/ha in 1989 and 6·1 t/ha in 1990, whereas those of direct-seeded maize averaged 4·0, 8·0 and 3·0 t/ha, respectively. The highest grain weights resulted from May plantings using 15-day-old seedlings of the late cv. Mirna, and from June plantings using 30-day-old seedlings. Yield benefits from transplanting were not significant in 1989, suggesting that in a very warm season transplants may not necessarily outyield direct-seeded crops. Differences in grain weight between transplanted and direct-seeded maize are discussed with respect to grain moisture content, 1000-grain weight, ear length, and number of grains and grain rows per ear; and applications of maize transplanting for cropping systems are outlined. It is concluded that suitable combinations of cultivar, transplant age at planting and planting date can meet the thermal time requirement for a grain harvest in southern England.