Effect of NPK Fertilizer on Growth, Flowering And Yield of Fonio (Digitaria exilis) in a Coastal Agro-Ecological Environment of Ghana

ABSTRACT

Fonio (Digitaria spp) is a neglected and underutilised crop traditionally grown in the Sahelian savannah agro-ecological zone of Ghana for its grain which is rich in crude protein, fibre and has medicinal properties. Decline in production of the crop is attributed to poor agronomic and yield characteristics and changing agro-climatic conditions as a result of global warming which has rendered traditional growing areas too dry to support cultivation of the crop. There is a need to explore the possibility of growing the crop in new agro-ecologies to sustain the production. The study was therefore conducted in Kwabenya-Atomic area which is located in the coastal savannah agro-ecological zone of Ghana, to evaluate the adaptability of three fonio landraces (Yadema, Nomber and Nvoni) to the coastal zone, their growth and response to NPK 15:15:15 fertiliser treatment, apparent fertiliser nitrogen recovery (AFNR) as well as presence of basic elements, in the grains. Field experiments were conducted in 2012 during the major cropping season, using three fonio landraces grown at a planting distance of 0.05 m 0.45 m. The experiment design used was the split plot in three replicates. Plants were sampled every two weeks throughout the growing season. Grain yield (GY) and its associated apparent fertiliser nitrogen recovery were significantly different (P ≤ 0.05) among the fonio landraces during the cropping season with the landrace Nvoni producing the highest grain yield of 964 kg ha−1 at NPK fertiliser rate of 60 kg ha−1 and with a AFNR of 33.1%. The study also established a positive correlation between biomass accumulation and grain yield. The efficiency of grain production per unit of fertiliser nitrogen (FN) increased, but at a diminishing rate with each additional unit of FN. Additionally, ten essential mineral elements (Na, Mg, K, Ca, I, Cl, Cu, Al, Mn and V) were detected among the grain of the three fonio landrace using Instrumental Neutron Activation Analysis (INAA).