Compost and Manure Effects on Sugarbeet Nitrogen Uptake, Nitrogen Recovery, and Nitrogen Use Efficiency

Abstract

To maximize recoverable sucrose from sugarbeet (Beta vulgaris L.), producers must effectively manage added N, be it from urea or organic sources such as manure or composted manure. Our study's objective was to determine the effects of a one‐time application of stockpiled and composted dairy cattle (Bos taurus) manure on sugarbeet N uptake, nitrogen recovery (NR) and nitrogen use efficiency (NUE). First‐year Site A treatments included a control (no N), urea (202 kg N ha−1), compost (218 and 435 kg estimated available N ha−1), and manure (140 and 280 kg available N ha−1). Site B treatments were a control, urea (82 kg N ha−1), compost (81 and 183 kg available N ha−1), and manure (173 and 340 kg available N ha−1). Compost and manure were incorporated into two silt loams, a Greenleaf (fine‐silty, mixed, superactive, mesic Xeric Calciargid) near Parma, ID, in fall 2002 and 2003 and a Portneuf (coarse‐silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid) near Kimberly, ID, in fall 2002 with sugarbeet planted the following spring. At each site, N uptake of sugarbeet tops, but not roots, was similar whether fertilized with urea or organic N, regardless of rate. Incorporating equal organic amendment rates to 0.05 rather than 0.10 m increased whole‐plant N uptake 1.13‐fold, to 163.3 kg N ha−1. In general, NR varied among fertilizer sources such that urea >> manure > compost. Where similar available N rates were supplied, NUE ranged from 44.1 to 83.5 kg sucrose kg−1 available N, not differing among inorganic and organic N sources within site‐years.