Williams Shanay T, Vail Sally, Arcand Melissa M
Department of Soil Science, University of Saskatchewan, Saskatoon, SK S7N 5A8, Canada.
Saskatoon Research Centre, Agriculture and Agri-Food Canada, Saskatoon, SK S7N 0X2, Canada.
Plants (Basel). 2021 Nov 2;10(11):2364. doi: 10.3390/plants10112364.
Improving nitrogen use efficiency (NUE) is essential for sustainable agriculture, especially in high-N-demanding crops such as canola (). While advancements in above-ground agronomic practices have improved NUE, research on soil and below-ground processes are limited. Plant NUE-and its components, N uptake efficiency (NUpE), and N utilization efficiency (NUtE)-can be further improved by exploring crop variety and soil N cycling. Canola parental genotypes (NAM-0 and NAM-17) and hybrids (H151857 and H151816) were grown on a dark brown chernozem in Saskatchewan, Canada. Soil and plant samples were collected at the 5-6 leaf stage and flowering, and seeds were collected at harvest maturity. Soil N cycling varied with phenotypic stage, with higher potential ammonium oxidation rates at the 5-6 leaf stage and higher urease activity at flowering. Seed N uptake was higher under higher urea-N rates, while the converse was true for NUE metrics. Hybrids had higher yield, seed N uptake, NUtE, and NUE, with higher NUE potentially owing to higher NUtE at flowering, which led to higher yield and seed N allocation. Soil N cycling and soil N concentrations correlated for improved canola NUE, revealing below-ground breeding targets. Future studies should consider multiple root characteristics, including rhizosphere microbial N cycling, root exudates, and root system architecture, to determine the below-ground dynamics of plant NUE.
提高氮素利用效率（NUE）对于可持续农业至关重要，尤其是对于油菜等高氮需求作物。虽然地上农艺实践的进步提高了氮素利用效率，但对土壤和地下过程的研究有限。通过探索作物品种和土壤氮循环，可以进一步提高植物的氮素利用效率及其组成部分，即氮吸收效率（NUpE）和氮利用效率（NUtE）。油菜亲本基因型（NAM - 0和NAM - 17）和杂交种（H151857和H151816）在加拿大萨斯喀彻温省的暗棕色黑钙土上种植。在5 - 6叶期和开花期采集土壤和植物样本，并在收获成熟时收集种子。土壤氮循环随表型阶段而变化，在5 - 6叶期潜在铵氧化率较高，在开花期脲酶活性较高。在较高尿素氮用量下种子氮吸收较高，而氮素利用效率指标则相反。杂交种具有更高的产量、种子氮吸收、氮利用效率和氮素利用效率，氮素利用效率较高可能是由于开花期较高的氮利用效率，这导致了更高的产量和种子氮分配。土壤氮循环与土壤氮浓度相关，有助于提高油菜的氮素利用效率，揭示了地下育种目标。未来的研究应考虑多种根系特征，包括根际微生物氮循环、根系分泌物和根系结构，以确定植物氮素利用效率的地下动态。
