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 bruis ing in potato tubers, this work was a preliminary study to determine whethe r the pattern of early-season nitrogen fertilizer application influences im pact 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 fr om two soils and three early-season nitrogen fertilizer application pattern s. Results showed that fertilizer pattern significantly influenced bruise t hreshold in the higher-permeability soil and bruise resistance in both soil s. 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 k g/ha postplant nitrogen treatment gave significantly higher bruise threshol d in the higher permeability soil and highest bruise resistance in both soi ls (higher is better). Fertilizer treatment effects were less pronounced in the lower permeability soil, with no significant effect on bruise threshol d in that soil. (C) 2000 Elsevier Science B.V. All rights reserved.