In the Nigerian derived savanna soil, organic matter is low, due to intensive cropping; consequently, nutrient balance is negative. A 2 year field study on an Alfisol in Ibadan, Nigeria to determine the effects of N (0 and 60 kg ha-1) and Fractional Recovery (FR) modulated P (amended P) (AP) (0, 15, 30, and 60 kg ha-1) on mineral N and P dynamics, uptake, and budgets revealed an 11% increase in cumulative N by AP rate over the control, while that of P was 20% less than the control. Nutrient uptake was enhanced by applications of N and P. The AP had the highest effect, and increased mean N and uptake by 19 and 16% over the control, respectively. The AP also increased N and P balance by 19 and 17% over the control. Soybean grain yield was 26% better than that of the 0P at the AP rate. Addition of 60 kg N kg ha-1 with AP gave the highest grain yield of 1.77 Mg ha-1. The dynamics of P in soil solution has a strong relationship with P uptake, leading to higher grain yield.