Socio-economic analysis of production and response of grain amaranth (amaranthus caudatus l.) to fertilizer application and intercropping with maize or beans in Kisumu West District, Kenya

Abstract

Protein malnutrition is widespread in developing countries due to prohibitive cost and low availability of animal protein foods and limited purchasing power of vulnerable groups. To ensure sufficient proteins for these vulnerable groups, alternative sources of cheap non-animal proteins must be sought. Grain amaranth is a promising option for meeting the protein requirements of the vulnerable groups in developing countries. It is a readily available and cheap plant food with protein quality and quantity comparable to those of animal foods. However, the crop is relatively new in Kenya. Its adoption and grain yields are low. In Kisumu West District, only 200 ha of the crop are grown annually against a cropped up area of 5800ha. The average grain yield is 1 t/ha compared to 2.5 t/ha achieved in other parts of the country. Determination of optimal fertilizer application rates and suitable intercropping patterns with staple crops could increase adoption and production. A strategy to boost production can be developed if current farmers' knowledge levels, utilization and perceptions of the crop together with agronomic, cultural and environmental factors that limit crop production and consumption are determined. Against this background, a survey was conducted in 2008 to document current knowledge, attitudes and practices (KAPs) regarding grain amaranth production and utilization in Kisumu West District, Kenya. Information was obtained from secondary sources and further investigated through Focus Group Discussions, key informant interviews and questionnaires administered to 84 farmers selected using stratified sampling techniques. Field experiments were conducted at the Maseno University Farm in the short rain season of 2008 and the long rain season of 2009 to determine the effect of intercropping grain amaranth with maize or beans and response of grain amaranth to nitrogen fertilizer and cattle manure. The rates of inorganic fertilizer tested were 0, 30, 60 and 100 kg N/ha. Cattle manure was applied at 0, 0.5, 1.0, 2.0 and 3.0 t/ha. The experiments were laid out in randomized complete block design and replicated three times. Single and double row intercrop arrangements were tested. Land equivalent ratios, aggressivity, relative crowding coefficients, competition ratios and gross margins for the intercrops were measured. Farmers' knowledge on grain amaranth processing (34.6%), utilization (34.6%) and medicinal value (13.2%) was low. Farmers identified and ranked seven constraints to grain amaranth production as; unreliable rainfall (60.7%); lack of awareness on crop husbandry and utilization (53.6%); lack of seed (38.1 %); lack of market (33.3 %); competition with other cereals (23.8%); inadequate capital (3.6%) and pests and diseases (2.4%). Double row intercrops had higher land equivalent ratios (1.44 -1.51) compared to single row (1.11-1.15) grain amaranth intercropping arrangements. In all intercropping arrangements, bean and maize intercrops showed variable LERs. In single row plant arrangements, maize and beans were dominant over grain amaranth but in double row intercrop arrangements, grain amaranth proved to be a better competitor. Maize showed the highest values of aggressivity (0.37), relative crowding coefficient (2.96) and competitive ratio (1.39) in single row arrangement. In double row intercrop arrangement, grain amaranth had the highest values of 0.38, 15.49 and 1.81 for aggressivity, relative crowding coefficient and competitive ratio, respectively. The highest grain yields, 2.1 and 1.94 t/ha, were achieved at the N rate of 100 kg/ha in 2008 and 2009 respectively. When manure was applied, the highest grain yields of 0.67 and 0.79 t/ha were obtained at the manure rate of 3 t/ha. Over the two years, bean/grain amaranth intercrop had 64% more returns compared to maize/grain amaranth intercrop. The optimum fertilizer rates based on regression analysis were 87.5 kg N/ha of inorganic fertilizer and 9.0 t/ha of cattle manure. The current results show that intercropping maize with grain amaranth is more compatible compared to bean/grain amaranth intercrop. Grain amaranth can be intercropped with maize or beans in either single or double rows but preferably in double rows for greater yield advantages. It is recommended that grain amaranth production in the district be done using inorganic fertilizer at the rate of 87.5 kg N/ha or cattle manure at the rate of 9.0 t/ha. Concerted efforts by all stakeholders would be required to address farmers' constraints in a holistic way to ensure sustainable production of grain amaranth. Further work should be done to determine the performance of the crop with application of a combination of organic and inorganic fertilizers. This is in addition to the socio-economic implications for introducing grain amaranth in the district.