Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
Xiamen Key Lab of Urban Metabolism, Xiamen 361021, China.
Int J Environ Res Public Health. 2019 Jul 29;16(15):2700. doi: 10.3390/ijerph16152700.
The Chinese government projected 30% of total consumed potatoes as a staple food (PSF) by 2020. We comprehensively assessed the potential impacts of PSF on rice and flour consumption, rice and wheat planting, energy and nutrient supply, irrigation-water, chemical nitrogen (N), phosphorus pentoxide (PO) and potassium oxide (KO) fertilizer inputs and total greenhouse gases (GHG) emission for potatoes, rice and wheat, by assuming different proportions of potato substitutes for rice and flour. The results showed that per capita, 2.9 ± 0.3 and 4.7 ± 0.5 kg more potatoes per year would enter the Chinese staple-food diet, under the government's target. PSF consumed are expected to reach 5.2 ± 0.7 Tg yr, equivalent to substituting potatoes for 4.2 ± 0.8-8.5 ± 0.8 Tg yr wheat and 5.1 ± 0.9-10.1 ± 1.8 Tg yr rice under different scenarios. While this substitution can increase the nutrient supply index by 63% towards nutrient reference values, it may induce no significant effect on staple-food energy supply with lower chemical fertilizer (except for KO) and irrigation-water inputs and GHG emissions in different substitution scenarios than the business as usual scenario. The reduction in rice and wheat demands lead to wheat in the North China Plain and early rice decrease by 6.1-11.4% and 12.1-24.1%, respectively. The total GHG reduction is equal to 1.1-9.0% of CO equivalent associated with CH and NO emitted from the Chinese agroecosystem in 2005. The saved irrigation water for three crops compared to 2012 reaches the total water use of 17.9 ± 4.9-21.8 ± 5.9 million people in 2015. More N fertilizer, irrigation-water, and GHG can be reduced, if the PSF ratio is increased to 50% together with potato yield improves to the optimal level. Our results implied that the PSF policy is worth doing not only because of the healthier diets, but also to mitigate resource inputs and GHG emissions and it also supports agricultural structure adjustments in the areas of irrigated wheat on the North China Plain and early rice across China, designed to increase the adaptability to climate change.
中国政府预计到 2020 年，将 30%的土豆消费作为主食（PSF）。我们通过假设不同比例的土豆替代大米和面粉，综合评估了 PSF 对大米和面粉消费、水稻和小麦种植、能源和养分供应、灌溉用水、化学氮（N）、五氧化二磷（PO）和氧化钾（KO）肥料投入以及土豆、水稻和小麦的总温室气体（GHG）排放的潜在影响。结果表明，在政府目标下，中国人均每年将增加 2.9 ± 0.3 和 4.7 ± 0.5 公斤土豆进入主食饮食。PSF 的消耗量预计将达到 5.2 ± 0.7Tg yr，相当于在不同情景下，用土豆替代 4.2 ± 0.8-8.5 ± 0.8Tg yr 的小麦和 5.1 ± 0.9-10.1 ± 1.8Tg yr 的水稻。虽然这种替代可以使营养素供给指数朝着营养素参考值增加 63%，但在不同替代情景下，与基准情景相比，它可能对主食的能量供应没有显著影响，且会降低化肥（除 KO 外）和灌溉水投入以及 GHG 排放。大米和小麦需求的减少导致华北平原的冬小麦和早稻分别减少 6.1-11.4%和 12.1-24.1%。与 2005 年中国农业生态系统排放的 CH 和 NO 相关的总 GHG 减排量相当于 CO 当量的 1.1-9.0%。与 2012 年相比，到 2015 年，三种作物的节水量将达到 1790 万人的总用水量（±4.9）-2180 万人的总用水量（±5.9）。如果将 PSF 比例提高到 50%，同时将土豆产量提高到最佳水平，那么可以减少更多的氮肥、灌溉用水和 GHG。我们的研究结果表明，实施 PSF 政策不仅是因为它能提供更健康的饮食，还因为它可以减少资源投入和 GHG 排放，并支持华北平原灌溉小麦和全国早稻等地区的农业结构调整，以提高适应气候变化的能力。
