Studies on the production of tigernut (Cyperus esculentus L.) in Southeastern Nigeria, II: Biochemical quality of tigernut in response to seven complementary fertilizer treatments

Abstract

Part I of this series showed significant influence of fertilizer on the growth and yield of tigernut. This paper documents the effects of these complementary fertilizers on the nutritional quality of the crop. Thus, the effects of seven fertilizer treatments on the nutritional quality of tigernut were studied. Proximate, mineral, vitamins and phytochemical contents of tigernut were evaluated across the fertilizer treatments. Most of the mineral contents were significantly (p < 0.05) influenced by the fertilizer combination except for magnesium (suggesting non-responsiveness of this mineral to fertilizer treatment). On the proximate contents, ash and moisture were statistically similar while other components varied significantly. The effect of fertilizer treatment on the vitamin content was only significant on vitamins B6 and C while for the phytochemical content, only phytates and tannin were significantly (p < 0.05) influenced by fertilizer. It was conclusive that combined application of organic and inorganic fertilizer increased the carbohydrate, fibre, vitamin C, tannin and most of the mineral contents of tigernut tubers. Findings reported herewith therefore validate the application of complementary fertilizer treatment for growing tigernut in this region because of enhanced nutritional quality of the tigernut seeds.