Abstract
The effects of N and P fertilization and their interaction on the onion (Allium cepa L.) seed crop, cv. D77, in a semiarid tropical soil were studied from November to April over a threeyear period (1988-91) under irrigation at Kadawa, Nigeria. Five N rates (0, 50, 100, 150, and 200 kg N ha-1) and four P rates (0, 25, 50, and 75 kg P ha-1) were tested. The main effects of N and P and their interaction on number of umbels per original bulb, seed weight per umbel, and seed yield were significant. There were no significant effects of N and P and their interaction on plant stand, and weight of 1000 seeds. At 50 kg P ha-1, the application of 50 or 100 kg N ha-1 gave significantly higher seed yield than other N and P rate combinations tested.
