Liang Xu, He Yanhu, Zhu Lirong, Fan Shijie, Zou Yi, Ye Changqing
College of Ecology and Environment, Hainan University, Haikou, 570228, China.
Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, China.
Environ Sci Pollut Res Int. 2022 Dec;29(56):85036-85049. doi: 10.1007/s11356-022-21853-z. Epub 2022 Jul 5.
The NUFER (Nutrient Flow in food chains, Environment and Resources) model has been used to reliably quantify nitrogen (N) and phosphorus (P) emissions from agriculture land to water bodies. However, factors impacting agricultural N and P emissions at the island scale have rarely been studied due to the lack of high-resolution spatialization tools, which are critical for exploring mitigation options. Here, a high-resolution NUFER model was constructed based on geology, meteorology, land-use data, statistical data, and field investigation. The spatial characteristics of N and P emissions in Hainan Island, China, were quantified, and the driving forces were analyzed. We also explored effective measures to reduce emissions by 2035 using scenario analysis. Overall, 98 Gg N from agriculture entered water bodies in 2018, of which crop system contributed 70%; 15 Gg P entered water bodies, of which, animal system contributed 78%. Nitrate (NO) leaching (65%) and direct discharge of animal manure (69%) accounted for most of the N and P emissions, respectively. Plains contributed 89% of N and 92% of P emissions. Spatial overlay analysis showed that high N and P emissions were mainly concentrated in the western and northeastern plain areas. At the sub-basin scale, the Nandu River basin had the largest agricultural N and P emissions, accounting for more than 20% of all emissions. Scenario analysis showed that N and P emissions were significantly correlated with natural (e.g., elevation, slope, and soil texture) and anthropogenic (e.g., rural income, population density, planting structure, and livestock density) factors. We further analyzed the emissions of N and P can be reduced by 71 Gg and 14 Gg by 2035, respectively, via reducing food chain waste and consumption, importing more food, and improving production efficiency, but especially prohibiting the direct discharge of livestock manure. This high-resolution quantification of agricultural N and P emissions to the water bodies provides an exploration of the most effective options for reducing agricultural non-point source (ANPS) pollution at the island scale.
NUFER（食物链、环境和资源中的养分流动）模型已被用于可靠地量化从农业用地到水体的氮（N）和磷（P）排放。然而，由于缺乏高分辨率空间化工具，岛屿尺度上影响农业氮磷排放的因素鲜有研究，而这些工具对于探索减排方案至关重要。在此，基于地质、气象、土地利用数据、统计数据和实地调查构建了一个高分辨率的NUFER模型。对中国海南岛氮磷排放的空间特征进行了量化，并分析了驱动因素。我们还通过情景分析探索了到2035年减少排放的有效措施。总体而言，2018年有98吉克氮从农业进入水体，其中作物系统贡献了70%；15吉克磷进入水体，其中动物系统贡献了78%。硝酸盐（NO）淋溶（65%）和动物粪便直接排放（69%）分别占氮磷排放的大部分。平原地区贡献了89%的氮排放和92%的磷排放。空间叠加分析表明，高氮磷排放主要集中在西部和东北部平原地区。在次流域尺度上，南渡江流域的农业氮磷排放最大，占总排放量的20%以上。情景分析表明，氮磷排放与自然因素（如海拔、坡度和土壤质地）和人为因素（如农村收入、人口密度、种植结构和牲畜密度）显著相关。我们进一步分析得出，到2035年，通过减少食物链浪费和消费、进口更多粮食以及提高生产效率，尤其是禁止牲畜粪便直接排放，氮磷排放量可分别减少71吉克和14吉克。这种对农业向水体排放氮磷的高分辨率量化为探索岛屿尺度上减少农业面源（ANPS）污染的最有效方案提供了依据。
