The Effect of Different Fertilization Regimes on Yield, Selected Nutrients, and Bioactive Compounds Profiles of Onion

Abstract

Here we report the results of a three-year replicated field trial on the effects of novel clover- and alfalfa-based fertilizer products (Ekofert® K and Ekofert® L), with the input levels equivalent to 120, 180, or 240 kg N ha−1, on the yield and selected sensory and nutritional quality parameters of onion. The study showed that Ekofert fertilizer applied at all three levels produced similar or higher yields than the standard fertilization regimes used in conventional farming in all three seasons. Significant differences in onion composition profiles between fertilization treatments were detected within individual seasons; however, due to substantial interseasonal variation, no consistent differences could be detected between (i) mineral N and Ekofert fertilizer treatments, (ii) the two different Ekofert products, and (iii) contrasting Ekofert input levels. Results demonstrate that clover- and alfalfa-based pelleted organic fertilizer products are a suitable alternative for intensive organic field vegetable production.

Keywords

• onion (<i>Allium cepa</i> L.)
• flavonoid compounds
• sugars
• organic acids
• vitamin C
• organic fertilization