Response of Onion (Allium Cepa L.) Growth and Yield to Different Combinations of N, P, S, Zn Fertilizers and Compost in Northern Ethiopia

Low soil fertility status is a limiting factor in northern Ethiopia in general and the study area in particular. To improve this problem and increase onion yield, balanced fertilization is a key important factor identified. However, use of correct type and rate of fertilizer applications are major problems in the study area. The objective of this research was, thus, to investigate the effect of three different combinations of N, P, S, Zn fertilizers and compost on yield and growth parameters of Adama red onion variety (Allium cepa L. ). A field experiment was conducted at a farmers field in Gumsalassa irrigation scheme in northern Ethiopia for the last two consecutive irrigation seasons (2012/2013 and 2013/2014). The experiment was laid out in randomized complete block design with three replications and five experimental plots (treated with N-P-S-Zn, N-P-S, N-P, compost and control) with unit plot size of 3m 3.5 m = 10.5 m2 and subjected to analysis of variance. Applied fertilizer rates were N=130, P=20, S=21, Zn=15 and Compost 12000 Kg he-1. As a result, all combinations of fertilizers including compost gave significantly higher yield as compared to the control (P=0.05). On an average, the study revealed that a considerable response of onion to N-P-S-Zn fertilizers was observed with a maximum average yield of 25377.5 kg he-1. Conversely, the minimum average yield (9810.5 kg he-1) was observed in the control plot. Accordingly combinations of 130 kg N, 20kg P, 21kg S and 15kg Zn ha-1 could be recommended for better yield over others.