Hydrolyzed Organic Fish Fertilizer and Poultry Litter Influence Total Phenolics and Antioxidants Content but Not Yield of Amaranth, Celosia, Gboma, and Long Bean

Abstract

Dietary intake of a variety of vegetables is very important for disease prevention and may help in the treatment of certain maladies. Experiments were conducted to evaluate yield and the content of antioxidants and phenolics of vegetable Amaranth (Amaranthus hybridus), Celosia (Celosia argentea), Gboma (Solanum macrocarpon), and Long Bean (Vigna unguiculata) in response to poultry litter (PL) and a hydrolyzed fish fertilizer [Megabloom (MB)]. The experiments were conducted as a randomized complete block design with a four × three factorial treatment and four replications. The treatments were applied based on soil test recommendations in a single band 15 to 20 cm away from the plants 1 week after transplanting. Plants were harvested sequentially during the season as foliage and fruits became physiologically mature and once over at the end of the season. Species were analyzed for vitamin C content, total phenolics, and β-carotene content as well as antioxidant capacity. Organic amendments did not significantly influence biomass production, whereas species impacted fresh and dry biomass. Amaranth, Celosia, and Long Bean produced greater fresh and dry biomass than did Gboma. Vitamin C content was highest among Amaranth and Celosia plants receiving nitrogen–phosphorus–potassium (NPK) compared with the other two treatments, whereas that of Gboma was higher among plants receiving MB.