nitrogen fertilization
Abo-Sedera, F. A., A. K. EL-Kafory, and S. A. Shehata,
"Effect of nitrogen fertilization and foliar spray with gibberellic acid and cycocel on flowering, seed yield and quality of onion. ",
Zagazig J. Agric. Res., , vol. 6, issue 20, pp. 1851- 1863., 1993.
