Spring Canola Yield Performance and Nitrogen Use Efficiency Assessment in Massachusetts.

Relatively high N rate is used to maximize canola seed yield which raise questions about its use as a biodiesel crop. Yield performance and NUE of spring canola was studied in Massachusetts condition. Two Roundup Ready hybrid cultivars were planted at two seeding rates (6 and 9 kg ha^-1) at four N rates (0, 56, 112, and 168 kg ha^-1). Averaged over all N application rates, the earlier maturity cultivar out-yielded the later maturity cultivar by 17%. Fertilizer recovery and NU_ptE were also higher in the earlier maturity cultivar. Seed yield increased linearly with increasing N application rate. However, fertilizer recovery response was parabolic where highest recovery (22.2%) was obtained from an application of 112 kg N ha^-1.  NU_ptE and NU_tE reduced linearly as N application rate increased.