Performance and environmental accounting of nutrient cycling models to estimate nitrogen emissions in agriculture and their sensitivity in life cycle assessment

Abstract

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.

Modelling direct field nitrogen emissions using a semi-mechanistic leaching model newly implemented in Indigo-N v3

“…The novelty of I-N3 lies in the better integration of mechanisms for the nitrate leaching component than in Tier 1 models reviewed by Buczko and Kuchenbuch (2010) or in Tier 2 models, such as the previous version of Indigo-N (Avadí et al, 2022) or the SALCA model (Nemecek et al, 2020), while maintaining the need of input data at reasonable level -i.e. considerably lower level compared to Tier-3 ones (Avadí et al, 2022;Pereira Andrade et al, 2021). The broad scope of the model is another progress in comparison with previous models.…”

“…This variety of management and pedoclimatic circumstances can be labelled as contrasting agricultural situations, which have been addressed by modellers via major nitrogen modelling efforts over the last decades (Bhar et al, 2021;Cannavo et al, 2008). Despite these efforts, the lack of a universally valid and operational model to estimate direct field emissions in the context of applications such as life cycle assessment (LCA) has been repeatedly indicated in the literature (Avadí et al, 2022;Nitschelm et al, 2018;Pereira Andrade et al, 2021;van Lent et al, 2015). Indeed, in the context of LCA, practitioners require simpler models rather than complex ones to estimate direct field emissions to be included in life cycle inventories (Avadí et al, 2022).…”

Critical analysis of life cycle inventory datasets for organic crop production systems

“…In terms of suggestions for improving organic fertilizer emissions modelling used in EI and AG, the meta-study by Andrade et al (2021) was used to determine which model may be more sufficient, as well as expert opinion (Angel Avadí, French National Institute for Agricultural Research, personal communication). Specific PPP emission modelling problems with copper can be found in the Results Sect.…”

“…3.2.2), many dynamic emissions models exist that may be suitable for organic fertilizers, such as Daisy (Hansen et al 2000) and Animo (Rijtema and Kroes 1991) which can be more dynamic than the SALCA model used by EI. These models have been reviewed in (Andrade et al 2021) for their robustness and applicability in LCA, among other characteristics, and the practitioner can decide which is more suitable for their case. Indigo v3.0 (Bockstaller et al 2020, submitted) is another model that looks at all types of emissions from S24, derived from Bittman et al 2014;Soogard et al 2002;Brentrup et al 2000, Montemayor et al 2019.…”

“…The COMIFER-Tailleur model used for NO 3 − emissions in AG, does not take into account dose and time of application Practitioners can use other more dynamic models that take these aspects into account: Indigo v3.0 (Bockstaller et al submitted), Daisy (Hansen et al 2000) and Animo (Rijtema and Kroes 1991), with meta-study by (Andrade et al 2021) Plant protection products (PPP) "Pesticide unspecified" dataset was used as a proxy for unavailable PPP production datasets This contains synthetic pesticides that are not authorized by OA regulations in Europe More research needed to create a regional "average OA-authorised PPP" dataset to replace "average pesticide, unspecified"…”