Purpose

Several models are available in the literature to estimate agricultural emissions. From life cycle assessment (LCA) perspective, there is no standardized procedure for estimating emissions of nitrogen or other nutrients. This article aims to compare four agricultural models (PEF, SALCA, Daisy and Animo) with different complexity levels and test their suitability and sensitivity in LCA.

Methods

Required input data, obtained outputs, and main characteristics of the models are presented. Then, the performance of the models was evaluated according to their potential feasibility to be used in estimating nitrogen emissions in LCA using an adapted version of the criteria proposed by the United Nations Framework Convention on Climate Change (UNFCCC), and other relevant studies, to judge their suitability in LCA. Finally, nitrogen emissions from a case study of irrigated maize in Spain were estimated using the selected models and were tested in a full LCA to characterize the impacts.

Results and discussion

According to the set of criteria, the models scored, from best to worst: Daisy (77%), SALCA (74%), Animo (72%) and PEF (70%), being Daisy the most suitable model to LCA framework. Regarding the case study, the estimated emissions agreed to literature data for the irrigated corn crop in Spain and the Mediterranean, except N₂O emissions. The impact characterization showed differences of up to 56% for the most relevant impact categories when considering nitrogen emissions. Additionally, an overview of the models used to estimate nitrogen emissions in LCA studies showed that many models have been used, but not always in a suitable or justified manner.

Conclusions

Although mechanistic models are more laborious, mainly due to the amount of input data required, this study shows that Daisy could be a suitable model to estimate emissions when fertilizer application is relevant for the environmental study. In addition, and due to LCA urgently needing a solid methodology to estimate nitrogen emissions, mechanistic models such as Daisy could be used to estimate default values for different archetype scenarios.

中文翻译：

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营养循环模型的性能和环境核算，以估算农业中的氮排放量及其在生命周期评估中的敏感性

目的

文献中有几种模型可用于估算农业排放。从生命周期评估（LCA）的角度来看，没有用于估算氮或其他营养素排放量的标准化程序。本文旨在比较具有不同复杂程度的四种农业模型（PEF，SALCA，Daisy和Animo），并测试它们在LCA中的适用性和敏感性。

方法

介绍了所需的输入数据，获得的输出和模型的主要特征。然后，根据《联合国气候变化框架公约》（UNFCCC）提出的标准修改版和其他相关研究，根据模型的潜在可行性评估模型的性能，以评估LCA中的氮排放，以期判断其在LCA中的适用性。最后，使用选定的模型估算了西班牙灌溉玉米案例研究中的氮排放量，并在完整的生命周期评估中对其进行了测试以表征其影响。

结果和讨论

根据这套标准，该模型的得分从高到低依次为：雏菊（77％），SALCA（74％），阿尼莫（72％）和PEF（70％），是雏菊最适合LCA框架的模型。关于案例研究，除N ₂ O排放量外，估算的排放量与西班牙和地中海灌溉玉米作物的文献数据相符。当考虑氮排放时，对于大多数最相关的影响类别，其影响特征显示差异高达56％。此外，在LCA研究中用于估算氮排放量的模型的概述显示，已经使用了许多模型，但并不总是以适当或合理的方式使用。

结论

尽管机械模型比较费力，主要是由于需要输入的数据量，该研究表明，当肥料的施用与环境研究相关时，雏菊可能是估算排放量的合适模型。此外，由于LCA迫切需要可靠的方法来估算氮排放，因此可以使用机械模型（例如Daisy）来估算不同原型场景的默认值。