Spatiotemporal variation patterns and aggregation of crop residue burning at county scale in Northeast China

Abstract

Crop residue burning (CRB) has been a major environmental concern in key agricultural regions of China. To reveal spatiotemporal patterns of CRB events, a county-level assessment in Northeast China was conducted using Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomalies and land cover data. The results revealed that cropland fire occurrence increased significantly from 2003 to 2019, and annual CRB occurrence from 2014 to 2019 was significantly higher than that from 2003 to 2013. The majority of detected CRB events occurred in spring and autumn, accounting for 58.50% and 28.98% of the total cropland fires, respectively. The time scan statistics showed that CRB events lasted for approximately 40 days each year and were more severe in spring than autumn. The number of cropland fires monitored by Terra and Aqua satellites was relatively more balanced, accounting for 49.74% and 50.26% of the total, respectively, indicating that farmers may intentionally burn crop residue at night. The counties with higher CRB intensity were mainly in the Songnen Plain, Sanjiang Plain, and along the main stream of the Liaohe River. The Moran’s I value of 0.054 to 0.452 for CRB intensity demonstrated a strong spatial autocorrelation at the county level. The local autocorrelation Getis-Ord showed 86 counties with significant hot spots and 91 counties with significant cold spots. The county-level temporal and spatial patterns of CRB events may be the results of policies and socio-economic conditions. This study could provide support for identifying the influencing factors of CRB and offer suggestions for crop residue management practices in this agriculture-dominant region.