1) The authors made an instrument to copy the shape of field-surface. We call the instrument “field-surface copying instrument.” The instrument has 50 spokes and the maximum measuring range is 100cm in length.
The use is as follow: Touch the lower sides of 50 spokes on the face of the field and read the upper sides of 50 spokes by a scale or photograph them. As stated above, the use is easy and the date is accurate.
2) We set up three methods to express the level of field-surface. They are standard deviation (δ^mm), level degree (D^mm(n%)), level per-centage [n%(D^mm)]. Every method was exact and useful.
3) Swelling percentage of field-surface after tillage can be measured accurately by the field-surface copying instrument and porosity can be calculated easily by the swelling percentage of field-surface.
4) The shape of field-surface after each tillage can be observed immediately by the field-surface copying instrument.