AbstractNo‐till cropping in the semiarid Central Great Plains increases water storage during fallowing, which allows farmers to use an intensive cropping sequence of winter wheat (Triticum aestivum L.)‐sorghum [Sorghum bicolor (L.) Moench]‐fallow‐winter wheat. The purpose of this 15N field study was to provide as complete accounting as possible of fertilizer N dynamics (changes in the NO3−N pool, fertilizer N uptake by plants, fertilizer N carryover effects, and mineralization and uptake of labeled N from wheat residues) for this intensive cropping sequence. Main‐plot treatments were 0, 56, and 112 kg N ha−1. Eight microplots were established within all main plots. For the main plots that received 56 and 112 kg N ha−1, two microplots received no K15NO3, and one of these microplots had its nonlabeled wheat residues exchanged with labeled residues. Six microplots were treated with K15NO3, one‐third received K15NO3 the first year, one‐third the second year, and one‐third both years. There was no detectable NO3 leaching. Mineralization, fertilizer application, and plant uptake had dramatic effects on the soil NO3−N pool. Both N rates increased the total N concentration and N uptake of aboveground biomass of the first wheat crop and the sorghum crop over the unamended treatment, whereas only the highest fertilizer N rate increased the total N uptake of the unfertilized second wheat crop. Plant N uptake transferred the majority of fertilizer NO3 to aboveground biomass, and crop residue deposition, immobilization, and mineralization maintained the fertilizer N in the top 60 cm of soil. At the end of the 4‐yr cropping sequence, 90 and 87% of the applied fertilizer N was accounted for at the 56 and 112 kg N ha−1 rates, respectively. Of this N, generally 24 to 28% remained in the soil. The 10 to 13% of the applied fertilizer N that was unaccounted for was probably lost by denitrification or NH3 volatilization.