Effects of Organic and Inorganic Nutrient Sources on the Growth, Total Chlorophyll and Yield of Three Bambara Groundnut Landraces in the Coastal Region of Cameroon

Growth and yield parameters of bambara groundnut [Vigna subterranea L. Verdc. landraces: White Seed Coat (WSC), Black Seed Coat (BSC) and Light Red Seed Coat (RSC)] were evaluated under organic and inorganic fertilization in order to determine the field performance, for the improvement of smallholder agriculture in Cameroon. Four fertilizer application rates (0, 3, 6 and 12 t ha-1) of Water Lettuce (WL) and Poultry Manure (PM) and four fertilization rates (0, 100, 150 and 200 kg ha-1) of N, P and K were used in a randomized complete block design experiment with four replications. Application of WL or PM at 12 t ha-1 significantly (p<0.001) increased leaf water content, plant dry weight and total chlorophyll content in RSC landrace. Application of PM at 12 t ha-1 increased significantly (p<0.001) the number of pods per plant, the number of seeds per pods, the 1000 grain weight, the grain yield and the pod yield in RSC landrace. Significant (p<0.001) increase in plant dry weight was observed in all landraces at 100 kg ha-1 N, P or K fertilization. The fertilization rates above 100 kg ha-1 N, P or K led to a decline in yield in all the bambara groundnut landraces compared to the optimum 100 kg ha-1 N, P or K fertilization. RSC landrace showed better growth and yield than WSC and BSC landraces revealing a greater response of this cultivar to fertilization.