Effects of fertilization on cumulating characteristics of dried matter mass of sweet corn

Field trials were conducted with spring sown sweet crop in 2007 and a fall sown one in 2008 to investigate the influence of fertilization on growth and development of sweet corn. The cultivar of Yuetian 9 was adopted as the test crop. It has been observed that dried matter mass maintained relatively high cumulating rates from seedling throughout all other growth stages for both sown dates. Two cumulating peaks were observed from node-elongating to tasseling and from silking to harvesting. In conditions of this study, supply of N was the dominant factor increasing dried matter mass and ear yield of sweet corn. Treatments with N fertilizers increased dried matter mass and ear yield in maturity by 445% and142.9%, 627% and 193%, respectively for the fall and spring sown crop. Based on the regression analysis, the optimum economic N, P2O5 and K2O rates were 373.8, 68.1 and 230.8 kg/ha, respectively for the spring sown crops. For the fall sown crop, optimum economic N rate was 371.4 kg/ha. In addition, appropriate N supply enhanced fresh ear weight, dried seed rate and vitamin C content of fresh seeds, while P and K fertilizations enhanced soluble sugar content of fresh seeds. Compared to fall sown sweet corn, the spring sown crop required 12 d more to reach maturity, and reduced dried matter mass and ear yield by 41.5% and 26.0% in average respectively. It was concluded that sown date had a significant influence on the growth and development of sweet corn.