Ciampitti Ignacio A, Lemaire Gilles
Department of Agronomy, Kansas State University, Manhattan, KS, United States.
Honorary Director of Research, INRAE-Lusignan, France.
Sci Total Environ. 2022 Jun 20;826:154125. doi: 10.1016/j.scitotenv.2022.154125. Epub 2022 Feb 24.
Maize (Zea mays L.) breeding is continuously moving forward yield gains for many fields crops, increasing dependency to technology such as high input seed costs and high use of nitrogen (N) fertilizers. For this crop, breeding improvement led to concomitantly enhancing N recovery and uptake but following a similar ratio relative to the plant biomass (W) and nitrogen nutrition index (NNI, as actual to critical N concentration) levels. The aim of this review is to provides new insights related to the true gains of N use efficiency (NUE) for maize over time and to propose new direction to target improvement on the effective use of N. Thus, the increase in fertilizer N for modern hybrids to attain greater yields lead to a greater dependency to N fertilization and potentially increasing the overall environmental risks for N losses associated to this practice. Contrarily to the improvement based on NUE, improving the intrinsic N uptake capacity (more N uptake per unit of biomass) is needed to maximize yield and the effective use of N. These results highlight that crop breeding should refocus to directly target an increase on the effective use of N, increasing the efficiency on using environmental resources while seeking for improving attainable yields. SYNOPSIS: Enhancing resilience of our production systems is critical for food security goals. This review highlights the need of investment on directly targeting improvement of the effective use of N not only to improve efficiency but to reduce the dependency to fertilization and environmental risks.
玉米（Zea mays L.）育种在许多大田作物的产量提升方面不断取得进展，这增加了对诸如高投入种子成本和高氮肥用量等技术的依赖。对于这种作物，育种改良在提高氮素回收和吸收的同时，相对于植物生物量（W）和氮营养指数（NNI，即实际氮浓度与临界氮浓度之比）水平，保持了相似的比例。本综述的目的是提供有关玉米氮素利用效率（NUE）随时间推移的实际提升的新见解，并提出针对氮素有效利用进行改良的新方向。因此，现代杂交种为实现更高产量而增加氮肥用量，导致对氮肥的依赖性增强，并可能增加与这种做法相关的氮素损失的总体环境风险。与基于NUE的改良相反，需要提高内在氮吸收能力（单位生物量吸收更多氮素）以实现产量最大化和氮素的有效利用。这些结果表明，作物育种应重新聚焦于直接提高氮素的有效利用，在提高可实现产量的同时提高环境资源利用效率。综述：增强我们生产系统的恢复力对于粮食安全目标至关重要。本综述强调了不仅要投资直接针对提高氮素有效利用进行改良，以提高效率，还要减少对施肥的依赖和环境风险。
