Ineffectiveness of urea in an Arenoferralsol from Kinshasa

Nitrogen is the first mineral element limiting the level of production of many agricultural cropping systems in the world. Paradoxically, this element, which represents a significant burden for the farmer, escapes the system and pollutes waterways, groundwater and the atmosphere. Also, the loss of nitrogen, in various forms is an issue of most concern in the world today. As part of this work, we used urea because it is the most concentrated nitrogen fertilizer (46% N) and the widely used in agricultural practice due to its other advantages, in particular the low cost of transport, handling, storage and spreading. Notwithstanding its concentration, the highest in nitrogen among fertilizers, its application requires certain precautions to counter its dissipation, which limiting its efficiency in agricultural practice. It appears from this study that the ineffectiveness of urea observed in the soil of Kinshasa is due particularly to ammoniacal volatilization, which can last up to 12 days, which raises the pH of the soil to a maximum threshold greater than 9. This is exacerbated by the very low nitrification power of this soil