The current agricultural system faces several challenges, the most important being the ability to feed the increasing world population and mitigate climate change. In this context, the improvement of fertilizers’ agronomic efficiency while reducing their cost and environmental impact is one of the biggest tasks. Available literature shows that many efforts have been made to develop innovative fertilizers defined as ‘smart fertilizers’, for which, different interpretations and definitions have been used. This paper aims to define, classify, and describe the new frontier of the so-called smart fertilizers with a particular focus on field-scale studies on herbaceous species. Most of the analysed papers associate the ‘smart’ concept to the controlled and/or slow release of nutrients, using both terms as synonymous. Some others broadened the concept, including the controlled release of nutrients to reduce the environmental impact. Based on our critical analysis of the available literature, we conclude that a fertilizer can be considered ‘smart’ when applied to the soil, it allows control over the rate, timing, and duration of nutrients release. Our new definition is: ‘Smart fertilizer is any single or composed (sub)nanomaterial, multi-component, and/or bioformulation containing one or more nutrients that, through physical, chemical, and/or biological processes, can adapt the timing of nutrient release to the plant nutrient demand, enhancing the agronomic yields and reducing the environmental impact at sustainable costs when compared to conventional fertilizers’.

Highlights

- A smart fertilizer allows to control the rate, timing and duration of nutrients release.
- Nanofertilizers are powder or liquid formulations which involve the synthesis, design and use of materials at the nanoscale level.
- Composite fertilizers are formulations containing nutrients mixed or coated with one or more materials that exploit synergy among materials.
- Bioformulations are fertilizers containing active or dormant microorganisms capable to trigger physiological growth responses in plants.
- Limited information is available for smart fertilizers on herbaceous crops in open field conditions.

当前的农业系统面临着若干挑战，最重要的是养活不断增长的世界人口和减缓气候变化的能力。在这种情况下，提高肥料的农艺效率同时降低其成本和环境影响是最大的任务之一。现有文献表明，已经做出许多努力来开发被定义为“智能肥料”的创新肥料，对此使用了不同的解释和定义。本文旨在定义、分类和描述所谓的智能肥料的新领域特别关注草本物种的田间规模研究。大多数分析的论文将“智能”概念与营养素的受控和/或缓慢释放相关联，将这两个术语用作同义词。其他一些人扩大了这一概念，包括控制释放营养物质以减少对环境的影响。根据我们对现有文献的批判性分析，我们得出结论，当施用于土壤时，肥料可以被认为是“智能”的，它可以控制养分释放的速度、时间和持续时间。我们的新定义是：'智能肥料是任何单一或复合（亚）纳米材料、多组分和/或包含一种或多种营养素的生物制剂，通过物理、化学和/或生物过程，可以根据植物养分需求调整养分释放的时间，与传统肥料相比，以可持续的成本提高农艺产量并减少对环境的影响。

强调

- 智能肥料可以控制养分释放的速度、时间和持续时间。
- 纳米肥料是粉末或液体配方，涉及纳米级材料的合成、设计和使用。
- 复合肥料是含有混合或涂有一种或多种材料的营养成分的配方，这些材料利用材料之间的协同作用。
- 生物制剂是含有能够触发植物生理生长反应的活性或休眠微生物的肥料。
- 可用于露天条件下草本作物智能肥料的信息有限。