Fig. 3. Total above ground plant N uptake and partitioning over the growing season in Pima cotton grown on Panoche clay loam in 1999 and 2000 as affected by N treatment. The control treatment received no N fertilizer while the amount of N applied in the other treatments was determined by subtracting early-season soil nitrate-N levels (top 0.6 m) from the target N levels of 56, 112, 168, and 224 kg N ha^–1. Vertical bars represent standard errors of means for total above ground N content.