Abstract: Temperature changes and their differences were analyzed and compared in a comparative test was conducted between the two planting modes of broader-row ridges with double-shallow-furrow film mulching and bare land in Fuyu County, one of the main maize producing regions of Heilongjiang Province, in May-June 2018,with the soil temperature of 5cm below ground and the near-surface air temperature of 5cm above ground were continuously observed for 24 hours. And the temperature-increasing characteristics and advantages of the shallow-furrow film mulching planting mode were further evaluated. Results show that compared with the bare land, the shallow-furrow film mulching planting mode has a significant warming effect. The temperature increase was mainly at the early stage of maize seed germination, emergence and early stage of seedling growth, that is, before the film mulch was broken and the air was released, and the surface soil temperature and near-surface air temperature significantly increased by 2.8℃ and 6.1℃, respectively. The temperature rose both in the daytime and at night, and the warming effect was greater during the day than at night. At the late stage of seedling growth, that is, after the film mulch was broken, the surface soil temperature and near-surface air temperature dropped slightly, but the temperature decrease was mainly in the daytime, while the temperature increase was distinct at night. The diurnal temperature range was reduced by 3−4℃ on average. During the filming period, the daily minimum temperature of surface soil temperature and near-surface air temperature showed consistent increase, and the minimum surface soil temperature increased significantly by 2.0℃. The shallow-furrow film mulching planting mode increased the integrated temperature by 35% compared with that of the bare land, and the growth period was reduced by 8 days. Results also show that the shallow-furrow film mulching planting mode has obvious effects on temperature increasing during the emergence and growth of maize seedlings, which can reduce the impact of low temperature and strong winds in the maize seedling period, and can provide the basis for improving the utilization rate of heat resources, scientific introduction and optimizing planting structures. This mode is fully operated by machines, which is easy and favorable for large-scale extension. It has vast potential for further application in maize production in cold regions like Heilongjiang Province and other northeastern regions.

Key words: Shallow-furrow film mulching, Maize, Seedling, Temperature increase