PRODUCTION AND QUALITY OF AMARANTHUS SPECIES UNDER DIFFERENT FERTILIZER TREATMENTS

Abstract

Two cultivars of two Amaranthus species (A. hybridus and A. hypochondriacus) were field grown during the summer-autumn months to study the effects of organic and inorganic fertilizers on their biomass production and nutritional quality. This was done in order to pave-way for commercialization of the crop as a leaf vegetable. Two fertilizer types (urea and broiler manure) and six fertilizer rates of (zero control without any fertilizer application) 0, 50, 75, 100, 125 and 150 kg N ha -1 were applied on the field in different treatment combinations (with the two amaranth species). Chlorophyll contents of leaves, biomass production, plant height, branch number and leaf area were determined six weeks after transplanting. Plant samples were analyzed for crude protein, fat, acid and neutral detergent fibre contents. Seed dry weight was determined at physiological maturity of the crop. The interactions between amaranth species, fertilizer type and rate of fertilizer application in relation to majority of the growth, yield and nutritional parameters determined were significant. The chlorophyll contents of amaranth were significantly higher in plants grown in urea treatment combinations than those grown in broiler manure treatment combinations. Furthermore, A. hypochondriacus treatment combinations had significantly higher chlorophyll contents than A. hybridus treatment combinations. The former also had significantly higher biomass production compared to A. hybridus treatment combinations. The dry weight of 32.56 g plant -1 observed in A. hypochondriacus was significantly higher than 29.44 g plant -1 observed in A. hybridus. There was no particular trend observed with regard to the rate of fertilizer application treatment combinations. In terms of the nutritional quality, A. hybridus had consistently higher mean crude protein, fat, acid and neutral detergent fibre contents than A. hypochoudriacus in all the treatment combinations. Furthermore, amaranth grown in urea treatment combinations also had higher mean crude protein, fat and neutral detergent fibre contents than those grown in the broiler manure treatment combinations.