Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 1999
Publication Date: N/A
Technical Abstract: Soybean maximum yield research has been conducted annually, 1977-98, at the OARDC, Wooster, OH. Most years, this test has averaged 4700 kg/ha with highest single entry yields of 5300 kg/ha. In 1982, averaged across varieties, the yield was 6000 kg/ha with 4 varieties exceeding 6700 kg/ha. It was postulated that these exceptionally high yields in 1982 were due to a very early warm spring, that resulted in the soybeans flowering 2 weeks earlier than normal (June 15 vs July 1). Thus the soybeans entered the reproductive period earlier in the growing season when the days were longer and the light intensity higher. Also the length of the reproductive period was increased. Similar early warm spring conditions occurred in 1998, providing the opportunity to test this hypothesis. Averaged across cultivars the soybeans yielded 5400 kg/ha with individual lines exceeding 6000 kg/ha. These results indicate there is a photo/thermal barrier to higher soybean yields most years. If full season soybean varieties could be developed that flower earlier under normal spring temperatures, these data indicate the yield potential of soybeans could be significantly increased.