Influence of Organic and Inorganic Manures on Macro-Nutrients, Micro-Nutrients and Anti-Nutrients in two Amaranth spp in Kiambu Couny, Kenya

An experiment was carried out to investigate the influence of organic and inorganic manure on macronutrients, micronutients and antinutrients in two Amaranth spp. The experimental design was Randomized Complete Block Design (RCBD) in a factorial arrangement with three replicates, consisting of three factors which are A. tricolar and A. cruentus Amaranth spps, three rates of NPK Compound fertilizer 17-17-17 at 0, 250 kg ha-1 and 500 kg ha-1.Three rates of quail organic manure at 8.45 t ha-1,16.9 t ha-1 and control (no fertilizer applied). Secondary metabolites were also investigated in the two amaranth species. The experiment was carried for two seasons. The result showed that, Nitrogen increased from 1.87% at control to 2.27% when 16.9 t ha-1+250kg ha-1 was applied in A. cruentus variety and at the same rate, A. tricolor had 1.79%, 2.93% at control and16.9 t ha-1+250 kg ha-1 respectively. In season one, at 16.9 t ha-1+250 kg ha-1 Nitrogen in A. cruentus increased from 2.27% to 2.73% but in A. tricolor the nitrogen content increased to 2.98% in the second season. The highest potassium was 1.03% in A. cruentus and the same variety recorded the highest potassium of 1.04% in the second season at 8.45 t ha-1 +500 kg ha-1.Iron increased from 69.58% at 16.9 t ha-1+250 kg ha-1 to 191.2% when 8.45 t ha-1+500 kg ha-1 of NPK was applied in A. cruentus. A. cruentus in season one at 8.45 t ha-1 +500 kg ha-1 had 40.33GAE/kgDM total phenolic content whereas A. tricolar at the same application had 40.67gGAEkg/DM, in season two A. cruentus had the highest total phenolic compound of 42.33 g GAE/kgDM. A. tricolor had 4.04 mg/100 gfw of oxalate in season one, in season two, A. cruentus had 3.25 mg/100 gfw whereas A. tricolor had 3.15mg/100gfw in season two.