Phosphorus (P) is essential for plant growth and crop production and quality. Much information is available on the effects of plant residue quality on rates of decomposition and N mineralization, but fewer studies have evaluated the relationship between residue quality and P release during decomposition. It has been suggested that plant residues may play an important role in this effect due to the P added to soil by residues. However, little is known about the changes in P pools during legume residue decomposition. Residues from Vicia faba L.and Brassica campestris L. with varying P concentrations were added to two kinds of soil with low available P concentration, and the concentration of various soil P pools were assessed by soil P fractionation on days 0, 14, 28, and 56. In this study, P speciation was determined using solution ³¹P nuclear magnetic resonance (NMR) spectroscopy to understand the potential fate of residue P in soils. The results showed that residue addition significantly increased cumulative respiration. The size of the P pools changed over time and was affected by both residue P concentration and soil type. For all plant samples, orthophosphate produced the most intense resonance in each spectrum and was the most abundant P species detected in shoot residue, which appeared to be related to their total P concentrations. For crop residues with higher total P concentrations, the greatest proportion was present as orthophosphate. More than 90% of the phosphorus detected in the plant residue was found to be orthophosphate and phosphate monoester. However, increasing plant concentration of total P did not affect pyrophosphate concentration. Olsen-phosphorus was highest when the experiment began (day 0) but decreased as the experiment progressed. The increase in residual P found in all residues indicated that part of the mineralized P was converted into stable organic and inorganic P, which occurred mainly in the initial phase. These changes were generally more pronounced in high- and medium-P residues than in low-P residues. More Resin-P, NaHCO₃-Pt, and cumulative respiration was detected in the acid purple soil than in the neutral purple soil, which may be attributed to the high Ca²⁺ concentration in the neutral purple soil. This study demonstrated that changes and transformations in soil P pools over time depend on residue P concentration and soil type, and that they have the potential to be delivered to soil in a form readily available to plants and soil microorganisms.