Assessing the circularity of nutrient flows related to the food system in the Okanagan bioregion, BC Canada.

Sean Smukler,Mario Giampietro,Kent Mullinix,Robin Harder

doi:10.1016/j.resconrec.2021.105842

Abstract

The “circular bioeconomy” is extensively discussed in science and policy, and its implementation in practice is considered to be a panacea for fixing many current sustainability problems. The circular bioeconomy crucially depends on biological and technical processes capable of recycling nutrients in the right mix, at the right pace, and using only renewable energy. The current lack of circularity of nutrient flows is a critical factor that hampers sustainable food and bioeconomy systems. If we are serious about the sustainability of food and bioeconomy systems, we have to develop more robust tools to study (diagnose) and explore (simulate) the factors determining the circularity of nutrient flows. This paper applies a novel analytical framework to assess the circularity of nutrient flows in modern food systems. This framework can help understand the potentialities of proposed changes in relation to reducing nutrient losses and the dependence on nutrients mined from finite deposits. More specifically, in this paper, we illustrate a quantitative assessment of the flows of nitrogen, phosphorus, potassium, and magnesium in a case study – the food system of the Okanagan bioregion in BC Canada. Our study suggests that the proposed approach is effective to inform nutrient management policies in bioregional food systems. In particular, an assessment of the openness of nutrient flows flags the importance of managing organic residuals for comprehensive nutrient recovery and reuse – an activity that is still often systematically neglected due to large feed and food imports and the availability of cheap synthetic fertilizers. This type of analysis is essential if we want to develop effective policies for more sustainable management of nutrients in food and bioeconomy systems.

Highlights

In recent years, the concepts of “nutrient circularity”, “closing the nutrient loop”, “circular nutrient solutions”, and “circular nutrient economy” have gained traction (Barquet et al, 2020; Cobo et al, 2019; Koppelmaki et al, 2021; Nesme and Withers, 2016; Robles et al, 2020; Rosemarin et al, 2020; van der Wiel et al, 2019; Zhao et al, 2020)
By following imports and exports upstream, all the way to nutrient inputs to agricultural production, and downstream, all the way to organic residual management, the analysis considered nutrient flows that relate to food production and consumption in the bioregion but lie entirely outside its spatial boundaries
If feed imports are taken into account, only about a quarter of the food consumed in the Okanagan comes from feed and food crops produced in the Okanagan, while the remaining three quarters come from outside the bioregion or is produced with feed from outside the bioregion

Summary

Introduction

The concepts of “nutrient circularity”, “closing the nutrient loop”, “circular nutrient solutions”, and “circular nutrient economy” have gained traction (Barquet et al, 2020; Cobo et al, 2019; Koppelmaki et al, 2021; Nesme and Withers, 2016; Robles et al, 2020; Rosemarin et al, 2020; van der Wiel et al, 2019; Zhao et al, 2020) This echoes the increasing understanding that, in order to mitigate nutrient pollution in water bodies and improve global nutrient security, societies around the world have to learn how to minimize nutrient inputs in agricultural production while maximizing the recovery of nutrients from organic residuals – such as crop and food residues and animal and human manures – for reuse in agriculture. It has generated problems both on the supply and on the sink side: linear nutrient flows severely compromise water quality (Steffen et al, 2015), nutrient security (Cordell et al, 2009; Manning, 2015; Razon, 2018), and soil health (Jones et al, 2013)

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Conclusion