Effect of Trachyte Powder, Human Urine and Reserved Water from Cooked Beans on Andosols Fertility in Cameroonian Western Highlands

Soil fertilization is one of the major way to sustain crop production. In the present paper, fertilization trials were carried out on Andosols developed on trachyte in the upper part of the Bambouto Mountains with trachyte powder, human urine, and reserved water from cooked beans. The first group of top soil samples was treated with trachyte powder at different rates, activated with water and incubated during nine months. The second group was treated with human urine, the third group was treated with reserved water from cooked beans, the fourth group was treated with the mixture on the two fluids, the fifth group was treated with rock powder at 25% activated with human urine, the sixth group was treated with rock powder at 25% activated with reserved water from cooked beans, the seventh group was treated with 25% of rock powder activated with the mixture of the two fluids, and incubated during three months. The experimental design was a randomized complete block in 3 replicates. The different treatments enhanced Forestier and Kamprath indicators. Human urine and reserved water from cooked beans improved the content of available phosphorus in the treated soils, but generated at the same time soil salinization at a grade ranging between low and midium. Those fluids highly enriched soils with exchangeable basic cations, particularly potassium and sodium, generating an unbalanced cationic ratio. Trachyte powder is the substrate and the two fluids the cover fertilizers. The most appropriate formulation suitable to ensure a sustainable fertilization of those Andosols is the mixture of the three different treatments.