An experiment was conducted in the Savelugu/Nanton Municipality in the Guinea Savanna zone of Ghana from July 2015 to December 2015 to evaluate the effect of four soybean genotypes and three plant spacing on nitrogen fixation, growth and yield of soybean. The experiment was conducted in a split-plot design and replicated in four different communities. The main plots consisted of four soybean genotypes: TGX 1904-6F, TGX 1955-4F, Soung-pungun and Jenguma. The sub-plots were made up of three plant spacing: 45 by 10 cm, 60 by 10 cm and 75 by 10 cm. Seeds were planted two per stand. The number of days to 50% flowering was influenced by soybean genotype with Soung-pungun taking the shortest time to flower while Jenguma took the longest time to flower. Both the number of nodules per plant and nodule dry weight were not significantly influenced by genotype nor plant spacing (p<0.05). Biomass yield at mid-podding varied from 4324 kg/ha with Soung-pungun to 7163 kg/ha with TGX 1955-4F with significant differences among genotypes. Plant spacing also significantly influenced biomass yield. Biomass yield ranged from 4830 kg/ha with 75 x 10 cm spacing to 6769 kg/ha with the 45 x 10 cm spacing. There were no significant differences between genotypes or plant spacing with regard to percentage N fixed but the amount of N fixed differed significantly among genotypes and among plant spacing. Both grain and biomass yields at harvest were not significantly influenced by genotype or plant spacing. However, Jenguma appears to be better in terms of grain and biomass yield than the other genotypes. Giving the changing climate Soung-pungun appears to be better placed for adaptability due to its early maturing nature and its comparable yield with Jenguma.
MSc and Bcs thesis, internship reports