Response of Soybean (Glycine max (L.) Merr.) to Application of Poultry manure and Mineral fertilizers in the Agro-ecological Zone III of Cameroon

Abstract

Declining soil fertility and inappropriate fertilizer application greatly reduce crop yields. A study was carried out at the experimental field of the Institute of Agricultural Research for Development (IRAD) Bambui, located in the agro-ecological zone III of Cameroon to assess the effects of poultry manure and inorganic fertilizers on the growth, nodulation and grain yield of soybean. The experiment was arranged in a randomized complete block design (RCBD) with three replications and four treatments (T1: control: no input, T2: 2.5 tons ha -1 poultry manure, T3: 200kg ha -1 NPK and T4:100kg ha -1 Urea). Experimental plots measuring 4m x 3m were laid out. Planting was done at a spacing of 50cm x 10cm (at the rate of 2 plants per stand) to maintain a plant population of 400,000 plants per hectare. All cultural practices were carried out from planting to harvesting. Data taken on plants included plant height (cm), number of leaves per plant, canopy spread per plant (cm), number of nodules per plant, number of efficient nodules per plant, nodule fresh and dry weights (g) per plant, number of pods per plant, pod fresh and dry weights (g) per plant, number of filled pods per plant and grain yield (tons ha -1 ). Analysis of Variance was carried out to find the differences between the various parameters and the LSD Fisher’s Test was used to compare the different treatments. The results of the experiment showed that the application of Poultry manure showed a more remarkable and significant (P˂0.05) increase in the growth, nodulation and yield of soybean. This was followed by the NPK fertilizer treatment which did not differ significantly (P˃0.05) from the control and urea treatments in terms of yield. This study confirms the role of poultry manure in improving soybean yield. From the results obtained, poultry manure may be recommended for increasing soybean yield in the study area. However, the application of NPK and Urea fertilizers can also increase soybean yield.