The burning of crop residues and trash is a common practice in the groundnut cropping areas in Congo. In order to study the effect of this farming system, soil rhizobia and yields in groundnut crops were compared with those obtained at different levels of phosphorus and potassium fertilization. In the first experiment, the burning farming system with and without liming was tested on the nodulation and yields of threeA. hypogaeacultivars. In the second one, a combination of four levels of phosphorus (0, 40, 80 and 120 kg P/ha) with three levels of potassium (0, 50 and 100 kg K/ha) were tested. In the third one, the four levels of P (0, 40, 80 and 120 kg P/ha) and Kat a rate of 50 kg K/ha were also tested. Results showed that burning increased the nodulation in groundnut crops by up to 91% and yields by up to 47–56%. Increasing the rate of phosphorus from 0 to 40 kg P/ha failed to enhance nodulation and pod yield. However, at a rate of 50 kg K/ha, phosphorus application at rates ranging from 40 to 120 kg P/ha increased the nodulation and yields in the groundnut crop by up to 57–176% and 17–54%, for nodulation and yields, respectively. Average increases ranging from 52–256% and 80–105% could be reached depending on field conditions.