Effect of Inorganic and Organic Fertilizers on the Performance and Profitability of Grain Amaranth (Amaranthus caudatus L.) in Western Kenya

Protein malnutrition is a major cause of morbidity and mortality in developing countries where the cost and availability of animal protein remain prohibitive. Grain amaranth (Amaranthus caudatus L) has the potential to substitute expensive animal protein. Its production and consumption is however low in Kenya. Nitrogen is a key limiting element in grain amaranth production. This study investigated the effects of different rates of inorganic nitrogen and cattle manure on the growth and yield of grain amaranth over a period of two years. Inorganic fertilizer at the rate of 100 kg N/ha significantly delayed flowering. Grain yield showed a linear response to inorganic and organic N application. Regression analysis projected the optimum inorganic fertilizer and manure application rates of 87.5 kg N/ha and 9 t/ha respectively with yield of 1.84 t/ha. The highest profitability was achieved at the optimum manure and fertilizer rates. The projected manure and inorganic fertilize rates may however not be affordable by the small-scale farmers. Thus a follow-up study to test the combined effect of inorganic and organic fertilizers is recommended.