Cabbage Nutritional Quality as Influenced by Planting Density and Nitrogen Fertilization June 2009

Abstract

A field experiment was conducted to investigate the effect of plant density and nitrogen fertilization levels on the growth, yield and nutritional quality of cabbage (Brassica oleracea L. var. capitata), during the two winter seasons of 2006 and 2007. Four rates of nitrogen fertilizer 0 (control), 30, 60, or 90 Kg N/feddan (1 feddan (fed) = 4200 m 2) were combined with three plant densities (2, 3, or 4 plants/drip) which resulted in a density of 4, 6, or 8 plants/m 2. Data showed that increasing both N fertilization rate and planting densities significantly increased plant height while head diameter, length, weight, edible head weight, and compactness rate were increased only with increasing N fertilization rate. However, a negative impact of the highest planting density on all these parameters was recorded. Total yield/fed significantly increased by increasing both N rate and planting density. The highest yield was obtained by the application of 90 kg N/fed combined with 8 plants/m 2. Increasing N fertilization rate increased total soluble solids (TSS) but decreased dry matter content; meanwhile, planting density did not significantly affect both of these parameters. Nitrogen, protein, and nitrate contents generally increased with increasing N fertilization rate but decreased with increasing planting density. Antioxidant capacity expressed as total phenols and vitamin C contents was positively affected by increasing N fertilization rate although it was not significantly affected by increasing planting density.