| National Tillage Machinery Laboratory@F@ Auburn now National Soil Dynamics Laboratory |
1940?- |
| Iowa State University@F@ Soil bin | 1955? |
| Deere & Company | 1966 |
| _±κij | 1958-1980? |
| _Ζ€Z^[@F@Kg[N[u | 1970?- |
| Odεw | 1965?- |
| OOεw | 1987- |
| ΡL{Yεw@F@Oπsͺθu | 1990?- |
| AIT@F @Soil bin devie | 1988 |
| μ_Ζ@B»€ | 1988 |
update 2000/01/03