Journal article

Publication year: 2022

Journal: Field Crops Research

Volume number: 283

ISSN: 0378-4290

eISSN: 1872-6852

Open access status: Bronze

DOI Link: https://doi.org/10.1016/j.fcr.2022.108527

Publisher: Elsevier

Abstract: 

Nitrogen (N) fertiliser inputs represent one of the largest variable costs in dryland cropping systems, and a key determinant of water-limited yield. Despite extensive research into microbial N losses via intermediate denitrification products such as N2O, limited research exists on total N losses, and the effect of increasing soil N surplus has on fertiliser use-efficiency is not clear. In this study, the fate of banded urea fertiliser N across crop uptake, soil residual N and N losses was determined using the N-15 recovery technique over nine trials with four N rates (0, plus low, medium and high industry rates) across N responsive and non-N responsive sites over 3 years in dryland sorghum (Sorghum bicolor). On average, crop uptake efficiency ranged from 50% at the low and medium N rate (80 kg N ha(-1)) to < 38% at the highest N rate, and was as low as 5%. Nitrogen losses averaged 26.5% across all rates and trials. At the medium N rate, losses exceeded 18% in all trials, despite relatively dry seasons, and in some trials exceeded 34%. Losses of N were driven by large cumulative rain events and high early-season rainfall. In dryland systems, the inability of crops to acquire banded N fertiliser can potentially leave fertiliser stranded in the topsoil, leaving it vulnerable to losses.

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Harvard Citation style: Rowlings, D., Lester, D., Grace, P., Scheer, C., De Rosa, D., Migliorati, M., et al. (2022) Seasonal rainfall distribution drives nitrogen use efficiency and losses in dryland summer sorghum, Field Crops Research, 283, Article 108527. https://doi.org/10.1016/j.fcr.2022.108527

APA Citation style: Rowlings, D., Lester, D., Grace, P., Scheer, C., De Rosa, D., Migliorati, M., Friedl, J., & Bell, M. (2022). Seasonal rainfall distribution drives nitrogen use efficiency and losses in dryland summer sorghum. Field Crops Research. 283, Article 108527. https://doi.org/10.1016/j.fcr.2022.108527