Delayed chilling stress is a frequent meteorological disaster in the spring maize-growing region of Northern China. Understanding the physiological responses and key characteristics of cold-tolerant maize varieties under such stress is crucial for their selection and utilization. This study compared the physiological and biochemical responses of a cold-tolerant variety (XY335) and a conventional variety (KH8) to simulated delayed chilling stress induced by early field sowing. Results showed that the emergence percentage and emergence uniformity of the cold-tolerant variety were 9.6% and 2.8% higher than those of the conventional variety, respectively. Under chilling stress, the root diameter of the cold-tolerant variety remained stable, while root length decreased by 24.5%. In contrast, the conventional variety exhibited the opposite response. Growth of the cold-tolerant variety slowed during stress but accelerated significantly after temperature recovery, achieving 1–2 more leaf ages than the conventional variety. The SPAD value (chlorophyll content) of the cold-tolerant variety was less affected, remaining 14.3% higher than the conventional variety, thereby maintaining higher photosynthetic efficiency. The enhanced stress tolerance of XY335 correlated with a robust antioxidant system: leaf peroxidase (POD) activity was 60.7% higher, and malondialdehyde (MDA) content was 42.4% lower compared to KH8. In summary, under delayed chilling stress, the cold-tolerant variety ensured higher emergence and seedling uniformity by reducing coleoptile length, maintained root diameter and absorption capacity by shortening root length, preserved chlorophyll synthesis and photosynthetic performance under the protection of a POD-dominated enzyme system, and employed a “standby mode” with compensatory leaf growth to ensure adequate dry matter accumulation and yield formation.

In view of various impacts on biosphere and possible cross-regional environmental problems, dust attracts global concerns. We employed multiple spatial resolution satellite images to identify dust sources and the relevantly hydrological land covers. We used true-colour composite images of MODIS to obtain the preliminary information on dust emissions and then distinguished the land covers of dust sources in Landsat images of Xilingol Grassland. The study found that hydrologically associated land covers, such as ephemeral lakes, bajadas, ephemeral river beds, dry lakes and their margins, dominated dust emission areas. Factors responsible for aeolian dusts are from both natural and human aspects. Besides abnormal weather phenomena, factors contributed to dust emissions include ecological and water balance destructions caused by human activities in alkali and coal exploitations and water pumping from rivers or lakes for agriculture and industry. This study will help grassland manager combat land desertification and control dust emission in the future.