The behavior of soil organic matter was evaluated in the rural area of the municipality of Buenaventura, specifically in the Zacarías district, which belongs to township #8 of the Dagua river, in the department of Valle del Cauca. This evaluation was conducted using different sources of phosphorus in the cultivation of rice (Oryza sativa L.). Two rice varieties were utilized in this study: a large Chinese variety from Guapi and a Fortaleza 5-30 variety from Jamundí. These were planted at a density of 110 kg/ha. A split plot design with three replications and eight treatments was employed, wherein the main plot represented the phosphate fertilization levels and the subplots represented the rice varieties. The phosphorus sources utilized in the course of this research were as follows: Diammonium phosphate (DAP 46%), Huila Phosphorite (22%), and Thomas Slag (10%) were applied to the soil at a rate of 50 kg/ha. The nitrogen source utilized was urea (46%) applied at a rate of 44 kg/ha, while potassium was applied as KCl (60%) at a rate of 100 kg. The findings of the study indicated that the rice variety that exhibited the greatest efficacy in utilizing phosphorus sources was the 5-30 strength variety. This variety demonstrated superior efficiency in utilizing this element in comparison to the large Chinese variety. No notable differences were observed between the soil treatments and the application of phosphorus fertilizers with respect to the variation of organic matter. The correlation between grain production (yield) and soil organic matter was 0.6.