Department of Biology, Lund University, Lund, Sweden.
Department of Entomology and Nematology, University of California, Davis, CA, USA.
Nat Commun. 2021 Sep 7;12(1):5310. doi: 10.1038/s41467-021-25615-2.
Nutritional stability - a food system's capacity to provide sufficient nutrients despite disturbance - is an important, yet challenging to measure outcome of diversified agriculture. Using 55 years of data across 184 countries, we assemble 22,000 bipartite crop-nutrient networks to quantify nutritional stability by simulating crop and nutrient loss in a country, and assess its relationship to crop diversity across regions, over time and between imports versus in country production. We find a positive, saturating relationship between crop diversity and nutritional stability across countries, but also show that over time nutritional stability remained stagnant or decreased in all regions except Asia. These results are attributable to diminishing returns on crop diversity, with recent gains in crop diversity among crops with fewer nutrients, or with nutrients already in a country's food system. Finally, imports are positively associated with crop diversity and nutritional stability, indicating that many countries' nutritional stability is market exposed.
营养稳定性——一个食物系统在受到干扰时提供足够营养的能力——是多样化农业的一个重要但难以衡量的结果。我们利用 184 个国家 55 年的数据，组装了 22000 个二分作物-养分网络，通过模拟一个国家的作物和养分损失来量化营养稳定性，并评估其与区域间、随时间推移以及进口与国内生产之间的作物多样性的关系。我们发现，各国的作物多样性与营养稳定性之间呈正相关关系，但也表明，除了亚洲以外，所有地区的营养稳定性在一段时间内都停滞不前或下降。这些结果归因于作物多样性的收益递减，最近在养分较少或已经在一个国家的食物系统中的作物中，作物多样性有所增加。最后，进口与作物多样性和营养稳定性呈正相关，这表明许多国家的营养稳定性都受到市场的影响。
