白洋淀流域农牧系统养分流动与环境损失时空特征

Temporal and spatial characteristics of nutrient flow and losses of the crop-livestock system in Baiyangdian Basin

  • 摘要: 随着农牧政策的实施及雄安新区的建立, 白洋淀流域农牧系统发生明显变化。本研究基于食物链养分流动模型(Nutrient flows in Food chains, Environment and Resources use, NUFER), 利用年鉴、调研和文献数据, 探讨2005年、2015年和2018年白洋淀流域县域尺度农牧系统氮磷账户、养分利用率以及环境损失特征。结果表明: 2018年白洋淀流域氮磷肥输入量显著低于2005年和2015年, 如氮肥输入量较2005年和2015年分别减少8.0%和11.6%; 2005年、2015年和2018年农田系统氮利用效率均为44%左右, 磷利用效率则由2005年27.1%上升至2018年30.7%。畜牧系统养分输入量和粪尿损失量显著降低, 2018年粪尿氮磷直排量分别是24.7 Gg和10.3 Gg, 仅为2015年的37%左右; 氮磷利用效率较2005年明显增加, 2018年氮磷利用效率分别为23.3%和18.6%。2018年农牧系统氮磷养分损失显著低于2005年和2015年, 而氮磷利用效率呈“先增后降”特征。空间上, 白洋淀流域农牧系统养分输入、输出和损失呈“东西低、中间高”特征。综上, 当前白洋淀流域已实现化肥“零增长”、畜禽粪尿优化管理的目标, 但农牧系统养分利用效率仍处于较低水平。农牧系统区域发展不平衡, 部分县域呈现高投入、高损失、低效率的特点。未来白洋淀流域农牧系统应深化化肥零增长政策, 继续推行畜禽废弃物资源化目标, 合理布局畜禽养殖数量, 实现农牧系统协同优化发展。

     

    Abstract: The crop-livestock system in Baiyangdian Basin has changed significantly owing to the implementation of related policies and establishment of the Xiong’an New Area. Based on the NUFER (Nutrient flows in Food chains, Environment and Resources use) model and data from statistical year books, surveys, and literatures, this study determined the nitrogen and phosphorus requirements for crop-livestock systems and analyzed the temporal and spatial characteristics of nutrient use and environmental losses in Baiyangdian Basin on a county scale in the years 2005, 2015, and 2018. The results showed that the inputs of nitrogen and phosphorus fertilizers in Baiyangdian Basin in 2018 were far less than those in 2005 and 2015. For example, the input of nitrogen fertilizer in 2018 was 8.0% and 11.6% lower than that in 2005 and 2015, respectively. The nitrogen use rate of the crop system remained at approximately 44% throughout the study period, whereas the phosphorus use rate increased from 27.1% to 30.7%. The total nutrient input and manure nutrient losses decreased significantly in the livestock system, especially for the directly discharge pathway, whose nitrogen and phosphorus losses reduced to 24.7 Gg and 10.3 Gg, respectively in 2018, which were only approximately 37% of that in 2015. Nitrogen and phosphorus use rates increased significantly for the whole livestock system, reaching 23.3% and 18.6%, respectively in 2018. In 2018, the nitrogen and phosphorus inputs in the crop-livestock system were significantly lower than those in the previous two study years. However, the nitrogen and phosphorus use rates of the whole crop-livestock system first increased and then decreased during 2005–2018. Spatial analysis revealed that the nutrient input, output, and loss of the crop-livestock system were relatively lower in the eastern and western Baiyangdian Basin but higher in the middle areas compared to those in other areas. In conclusion, the goal of “zero increase” in fertilizer and optimization of manure management was achieved in Baiyangdian Basin, but the nutrient use rates of the crop-livestock system were still at a low level. There was an unbalanced development pattern of crop-livestock systems; some counties were characterized by high input, high loss, and low efficiency. In the future, the Baiyangdian Basin should deepen the policy of zero increase in fertilizer, continue to implement the action of recycling livestock waste, and distribute animals rationally to ensure a synergistically optimized crop-livestock system.

     

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