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The undefined N source might be overestimated by 15 N tracer trials
Author(s) -
Quan Zhi,
Zhang Xin,
Fang Yunting
Publication year - 2021
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.15371
Subject(s) - fertilizer , agronomy , crop , nitrogen , tracer , environmental science , yield (engineering) , chemistry , biology , physics , nuclear physics , organic chemistry , thermodynamics
Based on data from previous 15 N‐tracer trials, Yan et al. ( Global Change Biology , 26, 191–199; 2020) accounted the sources of cereal crop nitrogen (N) from fertilizer inputs (from both current and previous seasons) and possible uptake of nonfertilizer N inputs, leaving a significant part of N source undefined. We argue that the undefined N source does not reflect the net change in soil N stock and might be overestimated for three reasons: (a) higher yield in 15 N tracer trials; (b) a low residue return rate is assumed; (c) underestimated contribution by fertilizer inputs from previous seasons due to the lack of long‐term trials.