EFFECTS OF ORGANIC AND INORGANIC FERTILIZERS ON SOIL CHEMICAL PROPERTIES AND THE YIELD OF Amaranthus species IN A CONTINUOUSLY CROPPED ULTISOL

Abstract

Field and laboratory experiments were conducted to evaluate the effects of poultry manure and NPK (20:10:10) fertilizer on soil chemical properties and yield of Amaranthus species. The treatments were: T1-Control (no fertilizer), T2-NPK 20:10:10 (200kg/ha), T3-Poultry manure (5 tons/ha), T4-NPK 20:10:10 (100kg/ha) + Poultry manure (2.5 tons/ha), T5-NPK 20:10:10 (100kg/ha)+ Poultry manure (5 tons/ha), T6-NPK 20:10:10 (200kg/ha)+ Poultry manure (5 tons/ha. The experiments were laid out in a randomized complete block design (RCBD). The soil was strongly acidic, having a pH of 5.1 and low in % total Nitrogen (0.10), % organic carbon (1.13) and the exchangeable bases. From the study, the poultry manure 5t/ha + NPK (20:10:10) 100kg/ha gave the best yield of Amaranthus species, followed by poultry manure 5t/ha + NPK (20:10:10) 200kg/ha which gave an increase in soil chemical properties. It is recommended that the combination of poultry manure 5t/ha + NPK (20:10:10) 100kg/ha fertilizer could be used for profitable Amaranthus production in the study area.