Compost and manure effects on sugarbeet nitrogen uptake, nitrogen recovery, and nitrogen use efficiency

To maximize recoverable sucrose from sugarbeet (Beta vulgaris L.), producers must effectively manage added nitrogen (N), whether it be from urea or organic sources such as manure or composted manure. Our multi-site study’s objective was to determine the effects of a one-time application of stockpiled and composted dairy cattle manure on sugarbeet N uptake, N recovery (NR) and N use efficiency (NUE). First-year treatments at Site 1 included a control (no N), urea (202 kg N/ha), compost (218 and 435 kg estimated available N/ha), and manure (140 and 280 kg available N/ha). Site 2 treatments were a control, urea (82 kg N/ha), compost (81 and 183 kg available N/ha), and manure (173 and 340 kg available N/ha). Compost and manure were incorporated into two silt loams, a Greenleaf (Xeric Calciargid) near Parma, ID, in fall 2002 and 2003 and a Portneuf (Durinodic Xeric Haplocalcid) near Kimberly, ID, in fall 2002 with sugarbeet planted the following spring. Sugarbeet N uptake was similar between urea and (i) manure, and (ii) often compost, when the organic amendments were averaged across rates. Incorporating equal rates of organic amendments to 0.05 rather than 0.10 m increased whole-plant N uptake by 1.13-fold, to 163.3 kg N/ha. In general, NR varied among fertilizer sources such that urea >> manure > compost. Where similar rates of available N were supplied, NUE ranged from 44.1 to 83.5 kg sucrose per kg available N, not differing among inorganic and organic N sources within site-years