Assessment of the Fertilizing effect of Vivianite on the Growth and yield of the Bean ''phaseolus vulgaris'' on Oxisoils from Ngaoundere (Central North Cameroon)

Abstract

The use of phosphate rocks has become agronomical and economically more beneficial compared to chemical fertilizers. In this study, the fertilizing effect of vivianite (a phosphorus rich mineral) from Hangloa on the growth and yield of the bean plant ‘‘Phaseolus vulgaris’’ on oxisoils from Ngaoundere is assessed. To this end, field investigations along with geochemical analysis, tests solubility and pot experiments have been carried out. Vivianite is located in the Hangloa lacustrine basin, situated at 25 km NW of the Ngaoundere town. Three different types of vivianite were identified: rosette, disk and vivianite in fragments within argillites. The solubility test was carried out by using the acid formic method. For the pot experiments, the design consists in a randomized complete block and constituted of two series of four treatments each: the control (T 0) without any addition of vivianite, the control with 20g of vivianite in the hole of sowing (T 1), the control with 20g of vivianite at the germination stage (T 2) and the control with 20g of vivianite at the flowering stage (T 3). Each treatment was replicated ten times. All the treatments were irrigated with 250 ml of water once every 2 days during the growing stage. The growth and yield parameters were measured after each three days. 12320 measures of growth components and 30721 measures of yield components were made. The geochemical analysis revealed that the vivianite of Hangloa has a high phosphorus content (9.17 %.) which can be easily dissolved in soil as revealed by the solubility test. A total dissolution rate of 53.48% was obtained at the end of experiment. The application of vivianite has a positive effect on the growth and the yield of the bean plant in the oxisoils from Ngaoundere: an increase of length and ramifications of stem, densification and extension of leaves, development of root system along with an increase of bean yield is observed in amended soils. The best periods for amendment of oxisoil with vivianite are the germination and flowering stages. The overall results indicate that vivianite can be used to enhance the bean crop yield in oxisoils from Ngaoundere and therefore is a good alternative local agromineral to chemical fertilizers commonly used.