Effects of industrial effluents and fertilizer applications on the growth, yield and nutritional quality of sunflower

Abstract

A field experiment was conducted in south-western Nigeria to determine  the effects of different fertilizer applications on the growth performance of sunflower when cultivated in an Alfisols contaminated with effluents from a paints industry. This was with a view to assessing the yield and nutrient quality of harvested sunflower grains. It was a randomised complete block design with three fertilizer applications [300 kg ha-1 of NPK 20-10-10 (IOF) ; 10,000 kg ha-1 of organomineral fertilizer (OMF) and control (CT)] ; and each was replicated thrice on the factory effluents impacted and un-impacted soils. At 10 weeks after planting, highest sunflower growth reduction rate (number of leaves 19.6 % ; plant height 3.9 % and stem girth 7.5 %) was obtained with OMF application when the impacted and un-impacted soils were compared. The highest mean yield of 1.17 t ha-1 obtained with OMF was not significantly (p < 0.05) higher than 0.80 t ha-1 obtained with IOF application, but significantly (p < 0.05) higher than 0.63 t ha-1 obtained in the controls with zero fertilizer application. The  un-impacted plots gave comparable but higher mean yields of sunflower. Highest concentrations of the nutrient elements and heavy metals were obtained in the grains of sunflower when OMF was applied. The results indicated that the quantity and quality of sunflower grains harvested from factory effluents impacted soil with or without fertilizer application were adversely affected ; hence cultivation of similar impacted soils with edible crops should be discouraged.

Keywords : Factory effluent, fertilizer, Nigeria, nutrient quality, paint industry, sunflower.