Objective  Effects of tillage methods applied for maize cultivation in northern Liaoning on the crop productivity and soil conditions were studied in search of an improved agriculture practice for the region.

  Method  Maize yield and soil properties under various tillage methods were determined in a field experimentation. Means of tillage and ground preparation including (A) rotary tillage for 15 cm, (B) deep loosing tillage for 30cm, (C) smash ridging tillage for 30 cm, (D) smash ridging tillage for 50cm, (E) smash ridging tillage for 30cm combined with film mulching, and (F) smash ridging tillage for 50cm combined with film mulching were evaluated. Ground temperature and bulk density in different layers of soil at different maize growth periods as well as root number, length, and volume and yield of maize plants were monitored.

  Result  Smash ridging tillage on the field increased the ground temperatures in layers of the soil. Significant rises of the soil temperature by 14.14-23.75% in maize seedling stage were observed when the tillage method was applied with film mulching, and by 14.34-25.90% in the maize jointing stage. Smash ridging tillage also reduced the bulk density in 25-30cm layer of soil by 1.91-3.09% at the maize seedling, jointing, and mature stages, and in the 45-50cm layer soil by 2.91-5.21%, while significantly increased the root count by 13.21-47.55%, the root length by 7.14-38.83%, and the root volume by 20.63-110.04% from the maize jointing stage to maturity stage. By covering the ground with a mulching film after smash ridging tillage, maize yield was increased by 11.12-16.29%. And the greatest increase in yield was achieved by using the (C) method with a 30 cm tillage.

  Conclusion  It was preliminarily showed that the smash ridging tillage with film ground cover, especially the method (C), could materially benefit not only the soil conditions but also the growth of maize root system and crop yield.