Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian, 116024, China.
Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian, 116024, China.
J Environ Manage. 2022 Nov 15;322:116099. doi: 10.1016/j.jenvman.2022.116099. Epub 2022 Sep 1.
Appropriate nitrogen (N) application increases crop yield, while its unreasonable application results in environmental problem. Determining the appropriate N application rate is the key to sustainable development. Here, the denitrification-decomposition (DNDC) model was used to analyze the effects of N fertilizer on maize yields, economic benefits, nitrate leaching, and nitrous oxide emissions in China. The N application rate for the trade-off between economy and environment at the county scale was further determined. The geodetector model was used to identify the main driving factors and their interactions of the recommended N rate in each agricultural zone. The results showed that the recommended N rate was generally high in the northwest but low in the south, consistent with the spatial patterns of yield potential. However, clay soils with clay ratios greater than 34% in southern China and sandy soils with bulk densities greater than 1.5 g cm on the Huanghuaihai Plain experienced high N levels and low yields, and thus soils need to be improved. Potential grain yield was the main driving factor in most zones, yet its effects gradually weakened from north to south. The influence of soil characteristics increased from north to south. It was found that the current average N application rate of farmers in China was 249 kg N/ha, and 86.55% of counties had excessive N applications. Compared to the regional optimal N rate at a regional scale, a differentiated N application strategy at the county scale determined in this study increased maize yield and economic benefit by 10.51% and 10.85%, respectively, and reduced NO emissions and NO leaching by 28.72% and 33.60%, respectively. The current research provides a scientific basis for China to formulate a win-win N management strategy for economy and environment and provides a method reference for other countries.
合理施用氮肥可以提高作物产量，而不合理施用则会带来环境问题。确定适宜的氮肥施用量是实现可持续发展的关键。本研究利用氮素淋失和反硝化-分解（DNDC）模型，分析了中国不同地区氮肥施用量对玉米产量、经济效益、硝态氮淋失和氧化亚氮排放的影响，并进一步确定了兼顾经济效益和环境效益的县域氮肥推荐施用量。利用地理探测器模型分析了各农业区推荐施氮量的主要驱动因素及其交互作用。结果表明，从西北到东南，推荐施氮量逐渐降低，与产量潜力的空间分布一致。然而，中国南方黏土比例大于 34%和黄淮海平原土壤容重大于 1.5 g·cm-3 的砂壤土，氮素水平高而产量低，需要改良土壤。在大多数地区，潜在粮食产量是主要的驱动因素，但从北到南，其影响逐渐减弱。土壤特性的影响则从北到南逐渐增强。研究发现，中国当前农民的平均氮肥施用量为 249 kg·N·ha-1，86.55%的县域氮肥投入过量。与区域最优施氮量相比，本研究确定的县域差异化施氮策略提高了玉米产量和经济效益，分别增加了 10.51%和 10.85%，减少了 28.72%和 33.60%的硝态氮淋失和氧化亚氮排放。本研究为中国制定兼顾经济和环境效益的氮素管理双赢策略提供了科学依据，也为其他国家提供了方法参考。
