KU Leuven, Department of Earth and Environmental Sciences, Division of Bio-economics, Celestijnenlaan 200E, 3001, Leuven, Belgium.
KU Leuven, Department of Earth and Environmental Sciences, Division of Bio-economics, Celestijnenlaan 200E, 3001, Leuven, Belgium.
J Environ Manage. 2021 Jun 15;288:112383. doi: 10.1016/j.jenvman.2021.112383. Epub 2021 Mar 27.
Nutrient reuse and recycling is a key strategy towards more circular and sustainable food systems and depends on the specific conditions of the area under study, such as geography and the type of agricultural system. In this study we analysed nutrient flows and assessed the circularity of a livestock-dominated and export-oriented agro-food system at different system levels and spatial scales. We quantified the nitrogen (N), phosphorus (P) and potassium (K) flows and soil balances in the Belgian agro-food system at the sub-regional, regional and national scale, and assessed five P-based indicators that capture different aspects of circularity: total inputs, phosphorus use efficiency, share of reused to total input, recycling rate, and losses. We found that nutrient soil balances depend on the type of agricultural system: areas with intense livestock production accumulate up to 108 kgN/ha, 4.8 kgP/ha and 150 kgK/ha in their soil annually, whereas areas of mostly arable production have low N and K surpluses of <20 kg/ha and P deficits of < -10 kg/ha. We further found that Wallonia, the southern region of the country that is characterized by lower livestock densities and a partial reuse of sewage sludge, outperforms the Flemish region in the North in all five indicators. The food system in the whole of Belgium has a 34% phosphorus use efficiency rate and a 63% overall recycling rate, while 84% of the total inputs in agriculture are from secondary sources. Our results show that the type of production system is the most crucial determinant for circularity, and highlight the benefit of working at different levels and spatial scales to capture all aspects of circularity in agro-food systems.
养分再利用和回收是实现更循环和可持续的食品系统的关键策略，这取决于研究区域的具体条件，如地理位置和农业系统类型。在本研究中，我们分析了养分流动，并在不同的系统水平和空间尺度上评估了以畜牧业为主导和面向出口的农业食品系统的循环性。我们量化了比利时农业食品系统在次区域、区域和国家尺度上的氮（N）、磷（P）和钾（K）流动和土壤平衡，并评估了五个基于 P 的指标，这些指标捕捉了循环性的不同方面：总投入、磷利用效率、再利用与总投入的份额、回收率和损失。我们发现，养分土壤平衡取决于农业系统的类型：以集约化畜牧业生产为主的地区每年在土壤中积累高达 108 千克 N/公顷、4.8 千克 P/公顷和 150 千克 K/公顷，而以主要种植作物为主的地区氮和钾的盈余量<20 千克/公顷，磷的亏缺量<-10 千克/公顷。我们进一步发现，与北部的佛兰德斯地区相比，以畜牧业密度较低和部分再利用污水污泥为特征的南部瓦隆大区在所有五个指标上都表现更好。整个比利时的食品系统的磷利用效率为 34%，总体回收利用率为 63%，而农业总投入的 84%来自二次资源。我们的研究结果表明，生产系统的类型是循环性的最关键决定因素，并强调了在不同水平和空间尺度上工作以捕捉农业食品系统中所有循环性方面的好处。
