南昌大学 | 中国农牧系统的氮困境:基于利用效率与污染热点视角评估减缓潜力并探索优化路径

图 6. 2022年中国不同作物与畜禽的氮流失量及环境损失强度。a，不同作物的氮素流失量；b，不同畜禽的氮素流失量；c，不同作物的环境损失强度；d，不同畜禽的环境损失强度。注：水果类别汇总了多种具体水果类型（如苹果、柑橘、梨、瓜类）的数据。具体作物参数详见补充表S5；LU，牲畜单位。

Fig. 6.N losses and environmental loss intensity of different crops and livestock in China in 2022. a, N loss of different crops; b, N loss of different livestock; c, Environmental loss intensity of different crops; d, Environmental loss intensity of different livestock. Notes: The “Fruit” category aggregates data from multiple specific fruit types (e.g., apple, mandarin, pear, melons). See Supplementary Table S5 for detailed crop-specific parameters; LU, livestock units.

图 7. 2022年不同地区氮损失。

Fig. 7. N loss in different regions in 2022.

图 8. 2000—2022年中国农牧系统氮损失空间分布特征及热点分析。a, 2000—2022年农牧系统氮径流和侵蚀损失强度；b, 2000—2022年农牧系统氮淋溶损失强度；c, 2000—2022年农牧系统氮粪污直排到水体损失强度；d, 2000—2022年农牧系统NH3损失强度；e, 2000—2022年农牧系统N2O损失强度；f, 2000—2022年农牧系统总氮损失强度。以2022年数据为基准，Group Ⅰ为0%—20%，Group Ⅱ为20%—40%，Group Ⅲ为40%—60%，Group Ⅳ为60%—80%，Group Ⅴ为80%—100%。其中Group Ⅴ部分定义为环境损失热点地区，其他为非热点地区

Fig. 8. Characteristics of spatial distribution of N losses and analysis of hotspots in China's crop-livestock systems, 2000—2022. a, Intensity of N runoff and erosion losses; b, Intensity of N leaching losses; c, Intensity of N direct discharge of manure; d, NH3 loss intensity; e, N2O loss intensity; and f, total N loss intensity. Based on 2022 data, Group Ⅰ is 0–20%, Group Ⅱ is 20%–40%, Group Ⅲ is 40%–60%, Group Ⅳ is 60%–80%, and Group Ⅴ is 80%–100%. Among them, Group Ⅴ is partially defined as environmental loss hotspots, and the others are non-hotspots.

图 9.不同区域农业氮管理指标对比及组间差异显著性分析。以2022年五组总氮损失（图8）为基准，其不同城市的氮相关指标箱线图：农牧系统氮利用效率、合成氮肥施用量、粪肥循环强度、秸秆循环强度、生物固氮强度、氮沉降强度、GDP、城镇化率、蔬菜和水果播种面积占总播种面积的比例、畜禽数量、规模化养殖数量、农业和牧业总产值。箱线图右侧为Tukey’s HSD分析结果，判定不同组别数据是否存在显著性差异，红色代表为显著性差异，黑色代表无显著性差异.

Fig. 9. Five groups of total N losses in 2022 (Fig. 8) as a baseline. The box line plots of N-related indicators for different cities are as follows: NUEc, N synthetic fertilizer application, manure cycle intensity, straw cycle intensity, biological N fixation, N deposition, GDP, urbanization rate, ratio of vegetable and fruit sown area to total sown area, number of livestock, number of large-scale farming, and total value of crop-livestock production. Notes: the right side of the box line plots shows Tukey's HSD analysis results to determine whether there is a significant difference in the data of different groups, with red representing a significant difference and black representing no significant difference.

图 10.中国农牧系统情景模拟结果。

Fig. 10.cenario simulation results for China's crop-livestock systems.

图 11.2022年，中国与其他国家化肥施用强度和不同作物单位面积产量对比。a）中国与其他国家化肥施用强度对比；b–i）中国单位面积水稻、小麦、玉米、薯类、豆类、苹果、梨和柑橘产量与部分国家对比。

Fig. 11.Comparison of N fertilizer application intensity and yields per unit area of different crops between China and other countries in 2022. a, Comparison of N fertilizer application intensity between China and other countries; b–i, Comparison of China's yields per unit area of rice, wheat, maize, potatoes, soybeans, apples, pears, and mandarins with other countries.

图 12.2000—2022年中国农牧系统绩效变化。a, 2000—2015年；b, 2015—2022年。注：畜牧业标准化养殖数量（以奶牛为标准单位）。黄色代表不同途径氮损失变化率；绿色代表农牧系统主产品氮和氮利用效率变化率；蓝色代表农业资源循环效率、粮食作物和经济作物播种面积、蔬菜和水果播种面积、畜禽养殖数量和规模化养殖数量变化率。

Fig. 12.Changes in the performance of China's crop-livestock systems, 2000–2022. a, 2000–2015; b, 2015–2022. Notes: “Production” refers to the total amount of N in crop and animal main products; “Livestock units” refers to the number of standardized livestock farms (in standard units of dairy cattle); “Large-scale share” refers to the number of large-scale livestock farms. Yellow represents the rate of change in N loss by different pathways; Green represents the rate of change in NUEc and the main products of the crop-livestock systems; and blue represents the rate of change in the efficiency of agricultural resource recycling, the sown area of grain crops and cash crops, the sown area of vegetables and fruits, the number of livestock farms, and the number of large-scale shares.

图 13.中国区域氮管理策略。

Fig. 13.Regional N differentiation management strategies in China.