The Influence of Rate and Time of Nitrogen Top Dressing on the Storage Quality of Onion (Allium Cepa L.)

Abstract

Onion (Allium cepa L.) is an important commercial vegetable crop grown by small-holder farmers in Kenya for both local and export markets. The national average production is low and quality is highly compromised due to use of low yielding varieties and poor agronomic practices. Field experiments on the influence of nitrogen and time of application on growth, yield, and quality of onion bulbs were conducted in 2014 and 2015 at the National Agricultural Research Laboratories. The experiments were laid out in a Randomized Complete Block Design (RCBD) with a split-split arrangement and replicated three times. Nitrogen (N) was applied as Calcium Ammonium Nitrate at five levels including, 0 (control), 26, 52, 78 and 104 kg N ha-1 . These were applied at four different times of applications at three, six, nine and twelve weeks after transplanting. Two onion varieties popularly grown in Kenya were used, the Red Creole and Red Tropicana F1 hybrid. Nitrogen and time of application showed significant differences in all parameters studied except bolting. Nitrogen