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Seasonal rainfall distribution drives nitrogen use efficiency and losses in dryland summer sorghum

Rowlings, D. W., Lester, D. W., Grace, P. R., Scheer, C., De Rosa, D., De Antoni Migliorati, M., Friedl, J. and Bell, M. J. (2022) Seasonal rainfall distribution drives nitrogen use efficiency and losses in dryland summer sorghum. Field Crops Research, 283 . p. 108527. ISSN 0378-4290

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Article Link(s): https://doi.org/10.1016/j.fcr.2022.108527

Publisher URL: https://www.sciencedirect.com/science/article/pii/S0378429022000983

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 15N 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.ga1

Item Type:Article
Business groups:Crop and Food Science
Subjects:Agriculture > Agriculture (General) > Agricultural meteorology. Crops and climate
Agriculture > Agriculture (General) > Methods and systems of culture. Cropping systems
Agriculture > Agriculture (General) > Fertilisers
Plant culture > Field crops > Sorghum
Deposited On:11 Apr 2022 04:51
Last Modified:11 Apr 2022 04:51

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