author(s)
Nuru Seid Tehulie, Selamsew Endeg, Amare Hunegnaw and Andualem Kebede

abstract
Onion is an herbaceous biennial monocot cultivated as an annual. In most research the greater seed yield in onion cultivars used to be due to the higher range of seed stalks per plant and to a wider umbel diameter which had been influenced through utility of Nitrogen and Phosphorus fertilizers. The wide variety of flower opening on every day was influenced by using the range of hours of sunshine and attention of phosphorous and nitrogen. Nitrogen and Phosphorus remedies tended to decrease bolting percentages. The yield of seed per plant extended as the nitrogen in the nutrient answer improved where seed stalks had been produced. The impact of early dressings of N on crops grown underneath stipulations when nights are turning into cooler is shown to permit the plants to reach a ‘bolting inducible’ stage early in the growing season. The early flowering via the application of P fertilizer used to be due to fact that phosphorus involvement in metabolic and physiological activities. The best possible costs of Phosphorus 115 and 147 kgha⁻¹ gives well boom and yield. There is most response of onions to Phosphorus fertilization in the range 0-52 kg ha^-1. Nitrogen fertilizer utility improves phosphorus uptake from the soil. Too lots phosphorus level influences plant boom by using suppressing the uptake of iron, potassium and Zink.