Nitrogen and Gray Water Footprints of Various Cropping Systems in Irrigation Districts: A Case from Ningxia, China

作者：Huan Liu, Xiaotong Liu, Tianpeng Zhang, Xinzhong Du, Ying Zhao, Jiafa Luo, Weiwen Qiu, Shuxia Wu, Hongbin Liu · 发表于：Water · 年份：2025 · DOI：10.3390/w17050717 · 被引用次数：4 · 研究领域：Environmental Impact and Sustainability、Agriculture Sustainability and Environmental Impact、Water-Energy-Food Nexus Studies

Under the influence of water resource conservation policies, the annual water diversion volumes in irrigation areas have been steadily decreasing, leading to substantial changes in regional cropping systems. These shifts have profoundly impacted agricultural reactive nitrogen (Nr) emissions and surface water quality. This study focuses on the Yellow River Irrigation area of Ningxia, China, and employs a life cycle assessment method to quantitatively analyze fluctuations in the nitrogen footprint (NF) and gray water footprint (GWF) across three cropping systems—rice-maize intercropping, rice monoculture, and maize monoculture—during 2021–2023. The results indicate that rice monoculture exhibited significant variability in NF values (197.89–497.57 kg Neq·ha−1), with NO₃− leaching identified as the primary loss pathway (102.33–269.48 kg Neq·ha−1). The GWF analysis revealed that in 2021, the region’s GWF peaked at 23.18 × 104 m3·ha−1, with water pollution predominantly concentrated in Pingluo County (8 × 104 m3·ha−1). LMDI analysis identified nitrogen fertilizer application as the main contributor to variations in NF, while surface water pollution was indirectly influenced by crop yield. Furthermore, gray correlation analysis highlighted a significant coupling relationship between NF and GWF, with nitrogen fertilizer application having the most pronounced impact on GWF. Therefore, in the face of the gradual tightening of water resources in the irrigation areas, the current situat...