The effects of chisel deep plowing and mole drain were evaluated in paddy field and upland field converted from paddy for improvement of sesame productivity. The Reguler underground drain was not set in both examined field. The combination of chisel deep plowing and mole drain was effective for improving of drainage in top soil, especially when more drain was connected with open ditch set along the levees. Such combination system led yield increase of sesame plants, which growth is usually damaged by excessive water in top soil.

The working time of a large tractor equipped with an automatic steering function during disc-harrow work was measured and compared with the case of manual steering （estimated value） in large crop field, Hokkaido.

In automatic steering tractors, because the duplicate work space can be narrowed in disc harrow work, tillage width by disc harrow increased and the number of tractors running for field tillage reduced compared to manual steering.

When turning on a headland, the automatic steering system used precise travel guidance to reduce the time required to turn.

From these system performance, automatic steering reduced the working time per field in harrow work, and the cultivated area per unit time was increased by 1.1 to 1.3 times compared to manual steering.