Influence of early-season nitrogen application pattern on impact sensitivity in Russet Burbank potato tubers

As part of an effort to assess the influence of cultural practices on bruising in potato tubers, this work was a preliminary study to determine whether the pattern of early-season nitrogen fertilizer application influences impact sensitivity (bruise threshold and bruise resistance) in Russet Burbank tubers. Tissue sample impact failure stress, strain, and shock wave speed, and whole-tuber bruise energy and bruise volume were measured on tubers from two soils and three early-season nitrogen fertilizer application patterns. Results showed that fertilizer pattern significantly influenced bruise threshold in the higher-permeability soil and bruise resistance in both soils. The worst fertilizer treatment resulted in bruises nearly twice the size of those in the other two treatments. The split 56 kg/ha preplant and 56 kg/ha postplant nitrogen treatment gave significantly higher bruise threshold in the higher permeability soil and highest bruise resistance in both soils (higher is better). Fertilizer treatment effects were less pronounced in the lower permeability soil, with no significant effect on bruise threshold in that soil. (C) 2000 Elsevier Science B.V. All rights reserved.