General situation of the research area

The research area was conducted at Liufangzi village, Gongzhuling city, Jilin Province (N43°34′10″, E124°52′55″), as shown in Fig. 8. The area has a continental monsoon climate in the humid area of the middle temperate zone, with an average annual precipitation of 594.8 mm, which is mainly concentrated in June and August. The average annual temperature is 5.6 °C, and the daily average temperature drops to 0 °C in November of each year, with a freezing period of up to five months. Corn is one of the main commodity crops in the area, with a sowing date in early May and a harvest date in early October.

Location of study area (Liufangzi Village, Gongzhuling City, Jilin Province).

The soil of the site is a silty loam black soil, which had been planted with monoculture corn with no tillage for 5 years. On October 5, 2018 (after the autumn harvest), a flat field was selected to set up the experiment. Soil samples were collected using the zigzag sampling method, and selective physical and chemical properties of soil were determined, including pH (5.48), organic matter (26.4 g kg⁻¹), clay (29.12%), and soil bulk density (1.21 g cm⁻³ in 5–10 cm and 1.53 g cm⁻³ in 20–25 cm).