Fertilization can change nitrogen availability in pine plantations, but growth response respect to magnitude and duration are not fully understood, particularly respect the long-term response. We studied monthly dynamics of nitrogen (availability, uptake and mineralization) in three trials of mid-rotation fertilization in Pinus radiata with contrasting soils (Chile, South America) for 2 years, where stands in sandy and granitic soils showed 5 to 6 years persistent growth responses to nitrogen fertilization, with gains volume of 24 m³ ha^-1 in sand and 51 m³ ha^-1 in granitic soils. However, red-clay soils did not respond 3 year after fertilization. Differences in long-term response between sites were mainly attributed to differences in soil nitrogen availability before the fertilization, and increases in the nitrogen mineralization rates in long-term. We found all sites increased nitrogen mineralization and availability rates, but granitic and sandy soil had higher uptake in fertilized treatment.