RESPONSE OF IRRIGATED ONION (Allium cepa L.) TO ORGANIC AND INORGANIC FERTILIZERS GROWN ON TWO SOIL TEXTURAL CLASSES OF TIGRAY, NORTHERN ETHIOPIA

Abstract

Soil fertility deterioration and availability of little information on approaches to improve it are the major causes for low onion productivity in Tigray. Thus, field experiment in response of irrigated onion to compost, blended (NPSZn) and potassium chloride (KCl) fertilizers on clay loam (CL) and loamy sand (LS) soil textural classes was carried out in 2018 and 2019 cropping seasons. Two compost (0, 20 t ha-1), three NPSZn (0, 60 and 120 kg ha-1) and four KCl (0, 120, 210 and 300 kg ha-1) rates replicated three times were arranged in split-split plot design and allocated to main, sub and sub-subplots respectively. Plant height, number of leaves per plant, bulb diameter, bulb height, total biomass and bulb yield data were collected and subjected to ANOVA using Gen stat. Results. These indicated that sole and combined application of the tested fertilizers significantly increased all measured parameters compared to the control. The highest bulb yield and yield component were obtained in plots treated at 20 t ha-1 compost with 120 kg ha-1 NPSZn and 210 kg ha-1 KCl. Bulb yield in 2018 (24.6 t ha-1 in CL, and 20.9 t ha-1 in LS) and 2019 (25.9 t ha-1 in CL, and 21.2 t ha-1 in LS) were obtained in plots treated with the above specified applications. Hence, it can be concluded that NPSZn and KCl application could be a viable strategy for advocating efficient use of chemical fertilizers with matching addition of compost.